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diff --git a/doc/lua-api/index.rst b/doc/lua-api/index.rst new file mode 100644 index 0000000..e8df63e --- /dev/null +++ b/doc/lua-api/index.rst @@ -0,0 +1,4491 @@ +.. toctree:: + :maxdepth: 2 + + +How Lua runs in HAProxy +======================= + +HAProxy Lua running contexts +---------------------------- + +The Lua code executed in HAProxy can be processed in 2 main modes. The first one +is the **initialisation mode**, and the second is the **runtime mode**. + +* In the **initialisation mode**, we can perform DNS solves, but we cannot + perform socket I/O. In this initialisation mode, HAProxy still blocked during + the execution of the Lua program. + +* In the **runtime mode**, we cannot perform DNS solves, but we can use sockets. + The execution of the Lua code is multiplexed with the requests processing, so + the Lua code seems to be run in blocking, but it is not the case. + +The Lua code is loaded in one or more files. These files contains main code and +functions. Lua has 8 execution contexts. + +1. The Lua file **body context**. It is executed during the load of the Lua file + in the HAProxy `[global]` section with the directive `lua-load`. It is + executed in initialisation mode. This section is use for configuring Lua + bindings in HAProxy. + +2. The Lua **init context**. It is a Lua function executed just after the + HAProxy configuration parsing. The execution is in initialisation mode. In + this context the HAProxy environment are already initialized. It is useful to + check configuration, or initializing socket connections or tasks. These + functions are declared in the body context with the Lua function + `core.register_init()`. The prototype of the function is a simple function + without return value and without parameters, like this: `function fcn()`. + +3. The Lua **task context**. It is a Lua function executed after the start + of the HAProxy scheduler, and just after the declaration of the task with the + Lua function `core.register_task()`. This context can be concurrent with the + traffic processing. It is executed in runtime mode. The prototype of the + function is a simple function without return value and without parameters, + like this: `function fcn()`. + +4. The **action context**. It is a Lua function conditionally executed. These + actions are registered by the Lua directives "`core.register_action()`". The + prototype of the Lua called function is a function with doesn't returns + anything and that take an object of class TXN as entry. `function fcn(txn)`. + +5. The **sample-fetch context**. This function takes a TXN object as entry + argument and returns a string. These types of function cannot execute any + blocking function. They are useful to aggregate some of original HAProxy + sample-fetches and return the result. The prototype of the function is + `function string fcn(txn)`. These functions can be registered with the Lua + function `core.register_fetches()`. Each declared sample-fetch is prefixed by + the string "lua.". + + .. note:: + It is possible that this function cannot found the required data in the + original HAProxy sample-fetches, in this case, it cannot return the + result. This case is not yet supported + +6. The **converter context**. It is a Lua function that takes a string as input + and returns another string as output. These types of function are stateless, + it cannot access to any context. They don't execute any blocking function. + The call prototype is `function string fcn(string)`. This function can be + registered with the Lua function `core.register_converters()`. Each declared + converter is prefixed by the string "lua.". + +7. The **filter context**: It is a Lua object based on a class defining filter + callback functions. Lua filters are registered using + `core.register_filter()`. Each declared filter is prefixed by the string + "lua.". + +8. The **event context**: Inside a function that handles events subscribed + through `core.event_sub()` or `Server.event_sub()`. + + +HAProxy Lua Hello world +----------------------- + +HAProxy configuration file (`hello_world.conf`): + +:: + + global + lua-load hello_world.lua + + listen proxy + bind 127.0.0.1:10001 + tcp-request inspect-delay 1s + tcp-request content use-service lua.hello_world + +HAProxy Lua file (`hello_world.lua`): + +.. code-block:: lua + + core.register_service("hello_world", "tcp", function(applet) + applet:send("hello world\n") + end) + +How to start HAProxy for testing this configuration: + +:: + + ./haproxy -f hello_world.conf + +On other terminal, you can test with telnet: + +:: + + #:~ telnet 127.0.0.1 10001 + hello world + +Usage of load parameters +------------------------ + +HAProxy lua-load(-per-thread) directives allow a list of parameters after +the lua file name. These parameters are accessible through an array of args +using this code `local args = table.pack(...)` in the body of loaded file. + +Below, a new version of the hello world using load parameters + +HAProxy configuration file (`hello_world.conf`): + +:: + + global + lua-load hello_world.lua "this is not an hello world" + + listen proxy + bind 127.0.0.1:10001 + tcp-request inspect-delay 1s + tcp-request content use-service lua.hello_world + +HAProxy Lua file (`hello_world.lua`): + +.. code-block:: lua + + local args = table.pack(...) + + core.register_service("hello_world", "tcp", function(applet) + applet:send(args[1] .. "\n") + end) + + +Core class +========== + +.. js:class:: core + + The "core" class contains all the HAProxy core functions. These function are + useful for the controlling of the execution flow, registering hooks, + manipulating global maps or ACL, ... + + "core" class is basically provided with HAProxy. No `require` line is + required to uses these function. + + The "core" class is static, it is not possible to create a new object of this + type. + +.. js:attribute:: core.emerg + + :returns: integer + + This attribute is an integer, it contains the value of the loglevel + "emergency" (0). + +.. js:attribute:: core.alert + + :returns: integer + + This attribute is an integer, it contains the value of the loglevel + "alert" (1). + +.. js:attribute:: core.crit + + :returns: integer + + This attribute is an integer, it contains the value of the loglevel + "critical" (2). + +.. js:attribute:: core.err + + :returns: integer + + This attribute is an integer, it contains the value of the loglevel + "error" (3). + +.. js:attribute:: core.warning + + :returns: integer + + This attribute is an integer, it contains the value of the loglevel + "warning" (4). + +.. js:attribute:: core.notice + + :returns: integer + + This attribute is an integer, it contains the value of the loglevel + "notice" (5). + +.. js:attribute:: core.info + + :returns: integer + + This attribute is an integer, it contains the value of the loglevel + "info" (6). + +.. js:attribute:: core.debug + + :returns: integer + + This attribute is an integer, it contains the value of the loglevel + "debug" (7). + +.. js:attribute:: core.proxies + + **context**: init, task, action, sample-fetch, converter + + This attribute is a table of declared proxies (frontend and backends). Each + proxy give an access to his list of listeners and servers. The table is + indexed by proxy name, and each entry is of type :ref:`proxy_class`. + + .. Warning:: + if you declared a frontend and backend with the same name, only one of + them will be listed. + + :see: :js:attr:`core.backends` + :see: :js:attr:`core.frontends` + +.. js:attribute:: core.backends + + **context**: init, task, action, sample-fetch, converter + + This attribute is a table of declared proxies with backend capability. Each + proxy give an access to his list of listeners and servers. The table is + indexed by the backend name, and each entry is of type :ref:`proxy_class`. + + :see: :js:attr:`core.proxies` + :see: :js:attr:`core.frontends` + +.. js:attribute:: core.frontends + + **context**: init, task, action, sample-fetch, converter + + This attribute is a table of declared proxies with frontend capability. Each + proxy give an access to his list of listeners and servers. The table is + indexed by the frontend name, and each entry is of type :ref:`proxy_class`. + + :see: :js:attr:`core.proxies` + :see: :js:attr:`core.backends` + +.. js:attribute:: core.thread + + **context**: task, action, sample-fetch, converter, applet + + This variable contains the executing thread number starting at 1. 0 is a + special case for the common lua context. So, if thread is 0, Lua scope is + shared by all threads, otherwise the scope is dedicated to a single thread. + A program which needs to execute some parts exactly once regardless of the + number of threads can check that core.thread is 0 or 1. + +.. js:function:: core.log(loglevel, msg) + + **context**: body, init, task, action, sample-fetch, converter + + This function sends a log. The log is sent, according with the HAProxy + configuration file, to the loggers relevant to the current context and/or + to stderr if it is allowed. + + The exact behaviour depends on tune.lua.log.loggers and tune.lua.log.stderr. + + :param integer loglevel: Is the log level associated with the message. It is a + number between 0 and 7. + :param string msg: The log content. + :see: :js:attr:`core.emerg`, :js:attr:`core.alert`, :js:attr:`core.crit`, + :js:attr:`core.err`, :js:attr:`core.warning`, :js:attr:`core.notice`, + :js:attr:`core.info`, :js:attr:`core.debug` (log level definitions) + :see: :js:func:`core.Debug` + :see: :js:func:`core.Info` + :see: :js:func:`core.Warning` + :see: :js:func:`core.Alert` + +.. js:function:: core.Debug(msg) + + **context**: body, init, task, action, sample-fetch, converter + + :param string msg: The log content. + :see: :js:func:`core.log` + + Does the same job than: + +.. code-block:: lua + + function Debug(msg) + core.log(core.debug, msg) + end +.. + +.. js:function:: core.Info(msg) + + **context**: body, init, task, action, sample-fetch, converter + + :param string msg: The log content. + :see: :js:func:`core.log` + +.. code-block:: lua + + function Info(msg) + core.log(core.info, msg) + end +.. + +.. js:function:: core.Warning(msg) + + **context**: body, init, task, action, sample-fetch, converter + + :param string msg: The log content. + :see: :js:func:`core.log` + +.. code-block:: lua + + function Warning(msg) + core.log(core.warning, msg) + end +.. + +.. js:function:: core.Alert(msg) + + **context**: body, init, task, action, sample-fetch, converter + + :param string msg: The log content. + :see: :js:func:`core.log` + +.. code-block:: lua + + function Alert(msg) + core.log(core.alert, msg) + end +.. + +.. js:function:: core.add_acl(filename, key) + + **context**: init, task, action, sample-fetch, converter + + Add the ACL *key* in the ACLs list referenced by the file *filename*. + + :param string filename: the filename that reference the ACL entries. + :param string key: the key which will be added. + +.. js:function:: core.del_acl(filename, key) + + **context**: init, task, action, sample-fetch, converter + + Delete the ACL entry referenced by the key *key* in the list of ACLs + referenced by *filename*. + + :param string filename: the filename that reference the ACL entries. + :param string key: the key which will be deleted. + +.. js:function:: core.del_map(filename, key) + + **context**: init, task, action, sample-fetch, converter + + Delete the map entry indexed with the specified key in the list of maps + referenced by his filename. + + :param string filename: the filename that reference the map entries. + :param string key: the key which will be deleted. + +.. js:function:: core.get_info() + + **context**: body, init, task, action, sample-fetch, converter + + Returns HAProxy core information. We can find information like the uptime, + the pid, memory pool usage, tasks number, ... + + This information is also returned by the management socket via the command + "show info". See the management socket documentation for more information + about the content of these variables. + + :returns: an array of values. + +.. js:function:: core.get_var() + + **context**: body, init, task, action, sample-fetch, converter + + Returns data stored in the variable <var> converter in Lua type. + This is limited to "proc." scoped variables. + + :param string var: The variable name in "proc." scope according with the + HAProxy variable syntax. + +.. js:function:: core.now() + + **context**: body, init, task, action + + This function returns the current time. The time returned is fixed by the + HAProxy core and assures than the hour will be monotonic and that the system + call 'gettimeofday' will not be called too. The time is refreshed between each + Lua execution or resume, so two consecutive call to the function "now" will + probably returns the same result. + + :returns: a table which contains two entries "sec" and "usec". "sec" + contains the current at the epoch format, and "usec" contains the + current microseconds. + +.. js:function:: core.http_date(date) + + **context**: body, init, task, action + + This function take a string representing http date, and returns an integer + containing the corresponding date with a epoch format. A valid http date + me respect the format IMF, RFC850 or ASCTIME. + + :param string date: a date http-date formatted + :returns: integer containing epoch date + :see: :js:func:`core.imf_date`. + :see: :js:func:`core.rfc850_date`. + :see: :js:func:`core.asctime_date`. + :see: https://tools.ietf.org/html/rfc7231#section-7.1.1.1 + +.. js:function:: core.imf_date(date) + + **context**: body, init, task, action + + This function take a string representing IMF date, and returns an integer + containing the corresponding date with a epoch format. + + :param string date: a date IMF formatted + :returns: integer containing epoch date + :see: https://tools.ietf.org/html/rfc7231#section-7.1.1.1 + + The IMF format is like this: + +.. code-block:: text + + Sun, 06 Nov 1994 08:49:37 GMT +.. + +.. js:function:: core.rfc850_date(date) + + **context**: body, init, task, action + + This function take a string representing RFC850 date, and returns an integer + containing the corresponding date with a epoch format. + + :param string date: a date RFC859 formatted + :returns: integer containing epoch date + :see: https://tools.ietf.org/html/rfc7231#section-7.1.1.1 + + The RFC850 format is like this: + +.. code-block:: text + + Sunday, 06-Nov-94 08:49:37 GMT +.. + +.. js:function:: core.asctime_date(date) + + **context**: body, init, task, action + + This function take a string representing ASCTIME date, and returns an integer + containing the corresponding date with a epoch format. + + :param string date: a date ASCTIME formatted + :returns: integer containing epoch date + :see: https://tools.ietf.org/html/rfc7231#section-7.1.1.1 + + The ASCTIME format is like this: + +.. code-block:: text + + Sun Nov 6 08:49:37 1994 +.. + +.. js:function:: core.msleep(milliseconds) + + **context**: body, init, task, action + + The `core.msleep()` stops the Lua execution between specified milliseconds. + + :param integer milliseconds: the required milliseconds. + +.. js:function:: core.register_action(name, actions, func [, nb_args]) + + **context**: body + + Register a Lua function executed as action. All the registered action can be + used in HAProxy with the prefix "lua.". An action gets a TXN object class as + input. + + :param string name: is the name of the action. + :param table actions: is a table of string describing the HAProxy actions + facilities where to expose the new action. Expected facilities are: + 'tcp-req', 'tcp-res', 'http-req', 'http-res', 'http-after-res'. + :param function func: is the Lua function called to work as an action. + :param integer nb_args: is the expected number of argument for the action. + By default the value is 0. + + The prototype of the Lua function used as argument is: + +.. code-block:: lua + + function(txn [, arg1 [, arg2]]) +.. + + * **txn** (:ref:`txn_class`): this is a TXN object used for manipulating the + current request or TCP stream. + + * **argX**: this is argument provided through the HAProxy configuration file. + + Here, an example of action registration. The action just send an 'Hello world' + in the logs. + +.. code-block:: lua + + core.register_action("hello-world", { "tcp-req", "http-req" }, function(txn) + txn:Info("Hello world") + end) +.. + + This example code is used in HAProxy configuration like this: + +:: + + frontend tcp_frt + mode tcp + tcp-request content lua.hello-world + + frontend http_frt + mode http + http-request lua.hello-world + +.. + + A second example using arguments + +.. code-block:: lua + + function hello_world(txn, arg) + txn:Info("Hello world for " .. arg) + end + core.register_action("hello-world", { "tcp-req", "http-req" }, hello_world, 2) + +.. + + This example code is used in HAProxy configuration like this: + +:: + + frontend tcp_frt + mode tcp + tcp-request content lua.hello-world everybody + +.. + +.. js:function:: core.register_converters(name, func) + + **context**: body + + Register a Lua function executed as converter. All the registered converters + can be used in HAProxy with the prefix "lua.". A converter gets a string as + input and returns a string as output. The registered function can take up to 9 + values as parameter. All the values are strings. + + :param string name: is the name of the converter. + :param function func: is the Lua function called to work as converter. + + The prototype of the Lua function used as argument is: + +.. code-block:: lua + + function(str, [p1 [, p2 [, ... [, p5]]]]) +.. + + * **str** (*string*): this is the input value automatically converted in + string. + * **p1** .. **p5** (*string*): this is a list of string arguments declared in + the HAProxy configuration file. The number of arguments doesn't exceed 5. + The order and the nature of these is conventionally chosen by the + developer. + +.. js:function:: core.register_fetches(name, func) + + **context**: body + + Register a Lua function executed as sample fetch. All the registered sample + fetch can be used in HAProxy with the prefix "lua.". A Lua sample fetch + returns a string as output. The registered function can take up to 9 values as + parameter. All the values are strings. + + :param string name: is the name of the sample fetch. + :param function func: is the Lua function called to work as sample fetch. + + The prototype of the Lua function used as argument is: + +.. code-block:: lua + + string function(txn, [p1 [, p2 [, ... [, p5]]]]) +.. + + * **txn** (:ref:`txn_class`): this is the txn object associated with the + current request. + * **p1** .. **p5** (*string*): this is a list of string arguments declared in + the HAProxy configuration file. The number of arguments doesn't exceed 5. + The order and the nature of these is conventionally chosen by the + developer. + * **Returns**: A string containing some data, or nil if the value cannot be + returned now. + + lua example code: + +.. code-block:: lua + + core.register_fetches("hello", function(txn) + return "hello" + end) +.. + + HAProxy example configuration: + +:: + + frontend example + http-request redirect location /%[lua.hello] + +.. js:function:: core.register_filter(name, Flt, func) + + **context**: body + + Register a Lua function used to declare a filter. All the registered filters + can by used in HAProxy with the prefix "lua.". + + :param string name: is the name of the filter. + :param table Flt: is a Lua class containing the filter definition (id, flags, + callbacks). + :param function func: is the Lua function called to create the Lua filter. + + The prototype of the Lua function used as argument is: + +.. code-block:: lua + + function(flt, args) +.. + + * **flt** : Is a filter object based on the class provided in + :js:func:`core.register_filter()` function. + + * **args**: Is a table of strings containing all arguments provided through + the HAProxy configuration file, on the filter line. + + It must return the filter to use or nil to ignore it. Here, an example of + filter registration. + +.. code-block:: lua + + core.register_filter("my-filter", MyFilter, function(flt, args) + flt.args = args -- Save arguments + return flt + end) +.. + + This example code is used in HAProxy configuration like this: + +:: + + frontend http + mode http + filter lua.my-filter arg1 arg2 arg3 + +.. + + :see: :js:class:`Filter` + +.. js:function:: core.register_service(name, mode, func) + + **context**: body + + Register a Lua function executed as a service. All the registered services + can be used in HAProxy with the prefix "lua.". A service gets an object class + as input according with the required mode. + + :param string name: is the name of the service. + :param string mode: is string describing the required mode. Only 'tcp' or + 'http' are allowed. + :param function func: is the Lua function called to work as service. + + The prototype of the Lua function used as argument is: + +.. code-block:: lua + + function(applet) +.. + + * **applet** *applet* will be a :ref:`applettcp_class` or a + :ref:`applethttp_class`. It depends the type of registered applet. An applet + registered with the 'http' value for the *mode* parameter will gets a + :ref:`applethttp_class`. If the *mode* value is 'tcp', the applet will gets + a :ref:`applettcp_class`. + + .. warning:: + Applets of type 'http' cannot be called from 'tcp-*' rulesets. Only the + 'http-*' rulesets are authorized, this means that is not possible to call + a HTTP applet from a proxy in tcp mode. Applets of type 'tcp' can be + called from anywhere. + + Here, an example of service registration. The service just send an + 'Hello world' as an http response. + +.. code-block:: lua + + core.register_service("hello-world", "http", function(applet) + local response = "Hello World !" + applet:set_status(200) + applet:add_header("content-length", string.len(response)) + applet:add_header("content-type", "text/plain") + applet:start_response() + applet:send(response) + end) +.. + + This example code is used in HAProxy configuration like this: + +:: + + frontend example + http-request use-service lua.hello-world + +.. js:function:: core.register_init(func) + + **context**: body + + Register a function executed after the configuration parsing. This is useful + to check any parameters. + + :param function func: is the Lua function called to work as initializer. + + The prototype of the Lua function used as argument is: + +.. code-block:: lua + + function() +.. + + It takes no input, and no output is expected. + +.. js:function:: core.register_task(func[, arg1[, arg2[, ...[, arg4]]]]) + + **context**: body, init, task, action, sample-fetch, converter, event + + Register and start independent task. The task is started when the HAProxy + main scheduler starts. For example this type of tasks can be executed to + perform complex health checks. + + :param function func: is the Lua function called to work as an async task. + + Up to 4 optional arguments (all types supported) may be passed to the + function. (They will be passed as-is to the task function) + + The prototype of the Lua function used as argument is: + +.. code-block:: lua + + function([arg1[, arg2[, ...[, arg4]]]]) +.. + + It takes up to 4 optional arguments (provided when registering), and no + output is expected. + + See also :js:func:`core.queue` to dynamically pass data between main context + and tasks or even between tasks. + +.. js:function:: core.register_cli([path], usage, func) + + **context**: body + + Register a custom cli that will be available from haproxy stats socket. + + :param array path: is the sequence of word for which the cli execute the Lua + binding. + :param string usage: is the usage message displayed in the help. + :param function func: is the Lua function called to handle the CLI commands. + + The prototype of the Lua function used as argument is: + +.. code-block:: lua + + function(AppletTCP, [arg1, [arg2, [...]]]) +.. + + I/O are managed with the :ref:`applettcp_class` object. Args are given as + parameter. The args embed the registered path. If the path is declared like + this: + +.. code-block:: lua + + core.register_cli({"show", "ssl", "stats"}, "Display SSL stats..", function(applet, arg1, arg2, arg3, arg4, arg5) + end) +.. + + And we execute this in the prompt: + +.. code-block:: text + + > prompt + > show ssl stats all +.. + + Then, arg1, arg2 and arg3 will contains respectively "show", "ssl" and + "stats". + arg4 will contain "all". arg5 contains nil. + +.. js:function:: core.set_nice(nice) + + **context**: task, action, sample-fetch, converter + + Change the nice of the current task or current session. + + :param integer nice: the nice value, it must be between -1024 and 1024. + +.. js:function:: core.set_map(filename, key, value) + + **context**: init, task, action, sample-fetch, converter + + Set the value *value* associated to the key *key* in the map referenced by + *filename*. + + :param string filename: the Map reference + :param string key: the key to set or replace + :param string value: the associated value + +.. js:function:: core.sleep(int seconds) + + **context**: body, init, task, action + + The `core.sleep()` functions stop the Lua execution between specified seconds. + + :param integer seconds: the required seconds. + +.. js:function:: core.tcp() + + **context**: init, task, action + + This function returns a new object of a *socket* class. + + :returns: A :ref:`socket_class` object. + +.. js:function:: core.httpclient() + + **context**: init, task, action + + This function returns a new object of a *httpclient* class. + + :returns: A :ref:`httpclient_class` object. + +.. js:function:: core.concat() + + **context**: body, init, task, action, sample-fetch, converter + + This function returns a new concat object. + + :returns: A :ref:`concat_class` object. + +.. js:function:: core.queue() + + **context**: body, init, task, event, action, sample-fetch, converter + + This function returns a new queue object. + + :returns: A :ref:`queue_class` object. + +.. js:function:: core.done(data) + + **context**: body, init, task, action, sample-fetch, converter + + :param any data: Return some data for the caller. It is useful with + sample-fetches and sample-converters. + + Immediately stops the current Lua execution and returns to the caller which + may be a sample fetch, a converter or an action and returns the specified + value (ignored for actions and init). It is used when the LUA process finishes + its work and wants to give back the control to HAProxy without executing the + remaining code. It can be seen as a multi-level "return". + +.. js:function:: core.yield() + + **context**: task, action, sample-fetch, converter + + Give back the hand at the HAProxy scheduler. It is used when the LUA + processing consumes a lot of processing time. + +.. js:function:: core.parse_addr(address) + + **context**: body, init, task, action, sample-fetch, converter + + :param network: is a string describing an ipv4 or ipv6 address and optionally + its network length, like this: "127.0.0.1/8" or "aaaa::1234/32". + :returns: a userdata containing network or nil if an error occurs. + + Parse ipv4 or ipv6 addresses and its facultative associated network. + +.. js:function:: core.match_addr(addr1, addr2) + + **context**: body, init, task, action, sample-fetch, converter + + :param addr1: is an address created with "core.parse_addr". + :param addr2: is an address created with "core.parse_addr". + :returns: boolean, true if the network of the addresses match, else returns + false. + + Match two networks. For example "127.0.0.1/32" matches "127.0.0.0/8". The + order of network is not important. + +.. js:function:: core.tokenize(str, separators [, noblank]) + + **context**: body, init, task, action, sample-fetch, converter + + This function is useful for tokenizing an entry, or splitting some messages. + :param string str: The string which will be split. + :param string separators: A string containing a list of separators. + :param boolean noblank: Ignore empty entries. + :returns: an array of string. + + For example: + +.. code-block:: lua + + local array = core.tokenize("This function is useful, for tokenizing an entry.", "., ", true) + print_r(array) +.. + + Returns this array: + +.. code-block:: text + + (table) table: 0x21c01e0 [ + 1: (string) "This" + 2: (string) "function" + 3: (string) "is" + 4: (string) "useful" + 5: (string) "for" + 6: (string) "tokenizing" + 7: (string) "an" + 8: (string) "entry" + ] +.. + +.. js:function:: core.event_sub(event_types, func) + + **context**: body, init, task, action, sample-fetch, converter + + Register a function that will be called on specific system events. + + :param array event_types: array of string containing the event types you want + to subscribe to + :param function func: is the Lua function called when one of the subscribed + events occur. + :returns: A :ref:`event_sub_class` object. + :see: :js:func:`Server.event_sub()`. + + List of available event types : + + **SERVER** Family: + + * **SERVER_ADD**: when a server is added + * **SERVER_DEL**: when a server is removed + * **SERVER_DOWN**: when a server state goes from UP to DOWN + * **SERVER_UP**: when a server state goes from DOWN to UP + * **SERVER_STATE**: when a server state changes + * **SERVER_ADMIN**: when a server administrative state changes + * **SERVER_CHECK**: when a server's check status change is reported. + Be careful when subscribing to this type since many events might be + generated. + + .. Note:: + Use **SERVER** in **event_types** to subscribe to all server events types + at once. Note that this should only be used for testing purposes since a + single event source could result in multiple events types being generated. + (e.g.: SERVER_STATE will always be generated for each SERVER_DOWN or + SERVER_UP) + + The prototype of the Lua function used as argument is: + +.. code-block:: lua + + function(event, event_data, sub, when) +.. + + * **event** (*string*): the event type (one of the **event_types** specified + when subscribing) + * **event_data**: specific to each event family (For **SERVER** family, + a :ref:`server_event_class` object) + * **sub**: class to manage the subscription from within the event + (a :ref:`event_sub_class` object) + * **when**: timestamp corresponding to the date when the event was generated. + It is an integer representing the number of seconds elapsed since Epoch. + It may be provided as optional argument to `os.date()` lua function to + convert it to a string according to a given format string. + + .. Warning:: + The callback function will only be scheduled on the very same thread that + performed the subscription. + + Moreover, each thread treats events sequentially. It means that if you + have, let's say SERVER_UP followed by a SERVER_DOWN in a short timelapse, + then the cb function will first be called with SERVER_UP, and once it's + done handling the event, the cb function will be called again with + SERVER_DOWN. + + This is to ensure event consistency when it comes to logging / triggering + logic from lua. + + Your lua cb function may yield if needed, but you're pleased to process the + event as fast as possible to prevent the event queue from growing up, + depending on the event flow that is expected for the given subscription. + + To prevent abuses, if the event queue for the current subscription goes + over a certain amount of unconsumed events, the subscription will pause + itself automatically for as long as it takes for your handler to catch up. + This would lead to events being missed, so an error will be reported in the + logs to warn you about that. + This is not something you want to let happen too often, it may indicate + that you subscribed to an event that is occurring too frequently or/and + that your callback function is too slow to keep up the pace and you should + review it. + + If you want to do some parallel processing because your callback functions + are slow: you might want to create subtasks from lua using + :js:func:`core.register_task()` from within your callback function to + perform the heavy job in a dedicated task and allow remaining events to be + processed more quickly. + +.. js:function:: core.disable_legacy_mailers() + + **LEGACY** + + **context**: body, init + + Disable the sending of email alerts through the legacy email sending + function when mailers are used in the configuration. + + Use this when sending email alerts directly from lua. + + :see: :js:func:`Proxy.get_mailers()` + +.. _proxy_class: + +Proxy class +============ + +.. js:class:: Proxy + + This class provides a way for manipulating proxy and retrieving information + like statistics. + +.. js:attribute:: Proxy.name + + Contain the name of the proxy. + + .. warning:: + This attribute is now deprecated and will eventually be removed. + Please use :js:func:`Proxy.get_name()` function instead. + +.. js:function:: Proxy.get_name() + + Returns the name of the proxy. + +.. js:attribute:: Proxy.uuid + + Contain the unique identifier of the proxy. + + .. warning:: + This attribute is now deprecated and will eventually be removed. + Please use :js:func:`Proxy.get_uuid()` function instead. + +.. js:function:: Proxy.get_uuid() + + Returns the unique identifier of the proxy. + +.. js:attribute:: Proxy.servers + + Contain a table with the attached servers. The table is indexed by server + name, and each server entry is an object of type :ref:`server_class`. + +.. js:attribute:: Proxy.stktable + + Contains a stick table object of type :ref:`sticktable_class` attached to the + proxy. + +.. js:attribute:: Proxy.listeners + + Contain a table with the attached listeners. The table is indexed by listener + name, and each each listeners entry is an object of type + :ref:`listener_class`. + +.. js:function:: Proxy.pause(px) + + Pause the proxy. See the management socket documentation for more information. + + :param class_proxy px: A :ref:`proxy_class` which indicates the manipulated + proxy. + +.. js:function:: Proxy.resume(px) + + Resume the proxy. See the management socket documentation for more + information. + + :param class_proxy px: A :ref:`proxy_class` which indicates the manipulated + proxy. + +.. js:function:: Proxy.stop(px) + + Stop the proxy. See the management socket documentation for more information. + + :param class_proxy px: A :ref:`proxy_class` which indicates the manipulated + proxy. + +.. js:function:: Proxy.shut_bcksess(px) + + Kill the session attached to a backup server. See the management socket + documentation for more information. + + :param class_proxy px: A :ref:`proxy_class` which indicates the manipulated + proxy. + +.. js:function:: Proxy.get_cap(px) + + Returns a string describing the capabilities of the proxy. + + :param class_proxy px: A :ref:`proxy_class` which indicates the manipulated + proxy. + :returns: a string "frontend", "backend", "proxy" or "ruleset". + +.. js:function:: Proxy.get_mode(px) + + Returns a string describing the mode of the current proxy. + + :param class_proxy px: A :ref:`proxy_class` which indicates the manipulated + proxy. + :returns: a string "tcp", "http", "syslog" or "unknown" + +.. js:function:: Proxy.get_srv_act(px) + + Returns the number of current active servers for the current proxy that are + eligible for LB. + + :param class_proxy px: A :ref:`proxy_class` which indicates the manipulated + proxy. + :returns: an integer + +.. js:function:: Proxy.get_srv_bck(px) + + Returns the number backup servers for the current proxy that are eligible + for LB. + + :param class_proxy px: A :ref:`proxy_class` which indicates the manipulated + proxy. + :returns: an integer + +.. js:function:: Proxy.get_stats(px) + + Returns a table containing the proxy statistics. The statistics returned are + not the same if the proxy is frontend or a backend. + + :param class_proxy px: A :ref:`proxy_class` which indicates the manipulated + proxy. + :returns: a key/value table containing stats + +.. js:function:: Proxy.get_mailers(px) + + **LEGACY** + + Returns a table containing mailers config for the current proxy or nil + if mailers are not available for the proxy. + + :param class_proxy px: A :ref:`proxy_class` which indicates the manipulated + proxy. + :returns: a :ref:`proxy_mailers_class` containing proxy mailers config + +.. _proxy_mailers_class: + +ProxyMailers class +================== + +**LEGACY** + +.. js:class:: ProxyMailers + + This class provides mailers config for a given proxy. + + If sending emails directly from lua, please consider + :js:func:`core.disable_legacy_mailers()` to disable the email sending from + haproxy. (Or email alerts will be sent twice...) + +.. js:attribute:: ProxyMailers.track_server_health + + Boolean set to true if the option "log-health-checks" is configured on + the proxy, meaning that all server checks event should trigger email alerts. + +.. js:attribute:: ProxyMailers.log_level + + An integer, the maximum log level that triggers email alerts. It is a number + between 0 and 7 as defined by option "email-alert level". + +.. js:attribute:: ProxyMailers.mailservers + + An array containing the list of mail servers that should receive email alerts. + Each array entry is a name:desc pair where desc represents the full server + address (including port) as described in haproxy's configuration file. + +.. js:attribute:: ProxyMailers.mailservers_timeout + + An integer representing the maximum time in milliseconds to wait for the + email to be sent. See "timeout mail" directive from "mailers" section in + haproxy configuration file. + +.. js:attribute:: ProxyMailers.smtp_hostname + + A string containing the hostname to use for the SMTP transaction. + (option "email-alert myhostname") + +.. js:attribute:: ProxyMailers.smtp_from + + A string containing the "MAIL FROM" address to use for the SMTP transaction. + (option "email-alert from") + +.. js:attribute:: ProxyMailers.smtp_to + + A string containing the "RCPT TO" address to use for the SMTP transaction. + (option "email-alert to") + +.. _server_class: + +Server class +============ + +.. js:class:: Server + + This class provides a way for manipulating servers and retrieving information. + +.. js:attribute:: Server.name + + Contain the name of the server. + + .. warning:: + This attribute is now deprecated and will eventually be removed. + Please use :js:func:`Server.get_name()` function instead. + +.. js:function:: Server.get_name(sv) + + Returns the name of the server. + +.. js:attribute:: Server.puid + + Contain the proxy unique identifier of the server. + + .. warning:: + This attribute is now deprecated and will eventually be removed. + Please use :js:func:`Server.get_puid()` function instead. + +.. js:function:: Server.get_puid(sv) + + Returns the proxy unique identifier of the server. + +.. js:function:: Server.get_rid(sv) + + Returns the rid (revision ID) of the server. + It is an unsigned integer that is set upon server creation. Value is derived + from a global counter that starts at 0 and is incremented each time one or + multiple server deletions are followed by a server addition (meaning that + old name/id reuse could occur). + + Combining server name/id with server rid yields a process-wide unique + identifier. + +.. js:function:: Server.is_draining(sv) + + Return true if the server is currently draining sticky connections. + + :param class_server sv: A :ref:`server_class` which indicates the manipulated + server. + :returns: a boolean + +.. js:function:: Server.is_backup(sv) + + Return true if the server is a backup server + + :param class_server sv: A :ref:`server_class` which indicates the manipulated + server. + :returns: a boolean + +.. js:function:: Server.is_dynamic(sv) + + Return true if the server was instantiated at runtime (e.g.: from the cli) + + :param class_server sv: A :ref:`server_class` which indicates the manipulated + server. + :returns: a boolean + +.. js:function:: Server.get_cur_sess(sv) + + Return the number of currently active sessions on the server + + :param class_server sv: A :ref:`server_class` which indicates the manipulated + server. + :returns: an integer + +.. js:function:: Server.get_pend_conn(sv) + + Return the number of pending connections to the server + + :param class_server sv: A :ref:`server_class` which indicates the manipulated + server. + :returns: an integer + +.. js:function:: Server.set_maxconn(sv, weight) + + Dynamically change the maximum connections of the server. See the management + socket documentation for more information about the format of the string. + + :param class_server sv: A :ref:`server_class` which indicates the manipulated + server. + :param string maxconn: A string describing the server maximum connections. + +.. js:function:: Server.get_maxconn(sv, weight) + + This function returns an integer representing the server maximum connections. + + :param class_server sv: A :ref:`server_class` which indicates the manipulated + server. + :returns: an integer. + +.. js:function:: Server.set_weight(sv, weight) + + Dynamically change the weight of the server. See the management socket + documentation for more information about the format of the string. + + :param class_server sv: A :ref:`server_class` which indicates the manipulated + server. + :param string weight: A string describing the server weight. + +.. js:function:: Server.get_weight(sv) + + This function returns an integer representing the server weight. + + :param class_server sv: A :ref:`server_class` which indicates the manipulated + server. + :returns: an integer. + +.. js:function:: Server.set_addr(sv, addr[, port]) + + Dynamically change the address of the server. See the management socket + documentation for more information about the format of the string. + + :param class_server sv: A :ref:`server_class` which indicates the manipulated + server. + :param string addr: A string describing the server address. + +.. js:function:: Server.get_addr(sv) + + Returns a string describing the address of the server. + + :param class_server sv: A :ref:`server_class` which indicates the manipulated + server. + :returns: A string + +.. js:function:: Server.get_stats(sv) + + Returns server statistics. + + :param class_server sv: A :ref:`server_class` which indicates the manipulated + server. + :returns: a key/value table containing stats + +.. js:function:: Server.get_proxy(sv) + + Returns the parent proxy to which the server belongs. + + :param class_server sv: A :ref:`server_class` which indicates the manipulated + server. + :returns: a :ref:`proxy_class` or nil if not available + +.. js:function:: Server.shut_sess(sv) + + Shutdown all the sessions attached to the server. See the management socket + documentation for more information about this function. + + :param class_server sv: A :ref:`server_class` which indicates the manipulated + server. + +.. js:function:: Server.set_drain(sv) + + Drain sticky sessions. See the management socket documentation for more + information about this function. + + :param class_server sv: A :ref:`server_class` which indicates the manipulated + server. + +.. js:function:: Server.set_maint(sv) + + Set maintenance mode. See the management socket documentation for more + information about this function. + + :param class_server sv: A :ref:`server_class` which indicates the manipulated + server. + +.. js:function:: Server.set_ready(sv) + + Set normal mode. See the management socket documentation for more information + about this function. + + :param class_server sv: A :ref:`server_class` which indicates the manipulated + server. + +.. js:function:: Server.check_enable(sv) + + Enable health checks. See the management socket documentation for more + information about this function. + + :param class_server sv: A :ref:`server_class` which indicates the manipulated + server. + +.. js:function:: Server.check_disable(sv) + + Disable health checks. See the management socket documentation for more + information about this function. + + :param class_server sv: A :ref:`server_class` which indicates the manipulated + server. + +.. js:function:: Server.check_force_up(sv) + + Force health-check up. See the management socket documentation for more + information about this function. + + :param class_server sv: A :ref:`server_class` which indicates the manipulated + server. + +.. js:function:: Server.check_force_nolb(sv) + + Force health-check nolb mode. See the management socket documentation for more + information about this function. + + :param class_server sv: A :ref:`server_class` which indicates the manipulated + server. + +.. js:function:: Server.check_force_down(sv) + + Force health-check down. See the management socket documentation for more + information about this function. + + :param class_server sv: A :ref:`server_class` which indicates the manipulated + server. + +.. js:function:: Server.agent_enable(sv) + + Enable agent check. See the management socket documentation for more + information about this function. + + :param class_server sv: A :ref:`server_class` which indicates the manipulated + server. + +.. js:function:: Server.agent_disable(sv) + + Disable agent check. See the management socket documentation for more + information about this function. + + :param class_server sv: A :ref:`server_class` which indicates the manipulated + server. + +.. js:function:: Server.agent_force_up(sv) + + Force agent check up. See the management socket documentation for more + information about this function. + + :param class_server sv: A :ref:`server_class` which indicates the manipulated + server. + +.. js:function:: Server.agent_force_down(sv) + + Force agent check down. See the management socket documentation for more + information about this function. + + :param class_server sv: A :ref:`server_class` which indicates the manipulated + server. + +.. js:function:: Server.tracking(sv) + + Check if the current server is tracking another server. + + :param class_server sv: A :ref:`server_class` which indicates the manipulated + server. + :returns: A :ref:`server_class` which indicates the tracked server or nil if + the server doesn't track another one. + +.. js:function:: Server.get_trackers(sv) + + Check if the current server is being tracked by other servers. + + :param class_server sv: A :ref:`server_class` which indicates the manipulated + server. + :returns: An array of :ref:`server_class` which indicates the tracking + servers (might be empty) + +.. js:function:: Server.event_sub(sv, event_types, func) + + Register a function that will be called on specific server events. + It works exactly like :js:func:`core.event_sub()` except that the subscription + will be performed within the server dedicated subscription list instead of the + global one. + (Your callback function will only be called for server events affecting sv) + + See :js:func:`core.event_sub()` for function usage. + + A key advantage to using :js:func:`Server.event_sub()` over + :js:func:`core.event_sub()` for servers is that :js:func:`Server.event_sub()` + allows you to be notified for servers events of a single server only. + It removes the needs for extra filtering in your callback function if you only + care about a single server, and also prevents useless wakeups. + + For instance, if you want to be notified for UP/DOWN events on a given set of + servers, it is recommended to perform multiple per-server subscriptions since + it will be more efficient that doing a single global subscription that will + filter the received events. + Unless you really want to be notified for servers events of ALL servers of + course, which could make sense given you setup but should be avoided if you + have an important number of servers as it will add a significant load on your + haproxy process in case of multiple servers state change in a short amount of + time. + + .. Note:: + You may also combine :js:func:`core.event_sub()` with + :js:func:`Server.event_sub()`. + + Also, don't forget that you can use :js:func:`core.register_task()` from + your callback function if needed. (ie: parallel work) + + Here is a working example combining :js:func:`core.event_sub()` with + :js:func:`Server.event_sub()` and :js:func:`core.register_task()` + (This only serves as a demo, this is not necessarily useful to do so) + +.. code-block:: lua + + core.event_sub({"SERVER_ADD"}, function(event, data, sub) + -- in the global event handler + if data["reference"] ~= nil then + print("Tracking new server: ", data["name"]) + data["reference"]:event_sub({"SERVER_UP", "SERVER_DOWN"}, function(event, data, sub) + -- in the per-server event handler + if data["reference"] ~= nil then + core.register_task(function(server) + -- subtask to perform some async work (e.g.: HTTP API calls, sending emails...) + print("ASYNC: SERVER ", server:get_name(), " is ", event == "SERVER_UP" and "UP" or "DOWN") + end, data["reference"]) + end + end) + end + end) + +.. + + In this example, we will first track global server addition events. + For each newly added server ("add server" on the cli), we will register a + UP/DOWN server subscription. + Then, the callback function will schedule the event handling in an async + subtask which will receive the server reference as an argument. + +.. _listener_class: + +Listener class +============== + +.. js:function:: Listener.get_stats(ls) + + Returns server statistics. + + :param class_listener ls: A :ref:`listener_class` which indicates the + manipulated listener. + :returns: a key/value table containing stats + +.. _event_sub_class: + +EventSub class +============== + +.. js:function:: EventSub.unsub() + + End the subscription, the callback function will not be called again. + +.. _server_event_class: + +ServerEvent class +================= + +.. js:class:: ServerEvent + +This class is provided with every **SERVER** events. + +See :js:func:`core.event_sub()` for more info. + +.. js:attribute:: ServerEvent.name + + Contains the name of the server. + +.. js:attribute:: ServerEvent.puid + + Contains the proxy-unique uid of the server + +.. js:attribute:: ServerEvent.rid + + Contains the revision ID of the server + +.. js:attribute:: ServerEvent.proxy_name + + Contains the name of the proxy to which the server belongs + +.. js:attribute:: ServerEvent.proxy_uuid + + Contains the uuid of the proxy to which the server belongs + +.. js:attribute:: ServerEvent.reference + + Reference to the live server (A :ref:`server_class`). + + .. Warning:: + Not available if the server was removed in the meantime. + (Will never be set for SERVER_DEL event since the server does not exist + anymore) + +.. js:attribute:: ServerEvent.state + + A :ref:`server_event_state_class` + + .. Note:: + Only available for SERVER_STATE event + +.. js:attribute:: ServerEvent.admin + + A :ref:`server_event_admin_class` + + .. Note:: + Only available for SERVER_ADMIN event + +.. js:attribute:: ServerEvent.check + + A :ref:`server_event_checkres_class` + + .. Note:: + Only available for SERVER_CHECK event + +.. _server_event_checkres_class: + +ServerEventCheckRes class +========================= + +.. js:class:: ServerEventCheckRes + +This class describes the result of a server's check. + +.. js:attribute:: ServerEventCheckRes.result + + Effective check result. + + Check result is a string and will be set to one of the following values: + - "FAILED": the check failed + - "PASSED": the check succeeded + - "CONDPASS": the check conditionally passed + +.. js:attribute:: ServerEventCheckRes.agent + + Boolean set to true if the check is an agent check. + Else it is a health check. + +.. js:attribute:: ServerEventCheckRes.duration + + Check's duration in milliseconds + +.. js:attribute:: ServerEventCheckRes.reason + + Check's status. An array containing three fields: + - **short**: a string representing check status short name + - **desc**: a string representing check status description + - **code**: an integer, this extra information is provided for checks + that went through the data analysis stage (>= layer 5) + +.. js:attribute:: ServerEventCheckRes.health + + An array containing values about check's health (integers): + - **cur**: current health counter: + - 0 to (**rise** - 1) = BAD + - **rise** to (**rise** + **fall** - 1) = GOOD + - **rise**: server will be considered as operational after **rise** + consecutive successful checks + - **fall**: server will be considered as dead after **fall** consecutive + unsuccessful checks + +.. _server_event_state_class: + +ServerEventState class +====================== + +.. js:class:: ServerEventState + +This class contains additional info related to **SERVER_STATE** event. + +.. js:attribute:: ServerEventState.admin + + Boolean set to true if the server state change is due to an administrative + change. Else it is an operational change. + +.. js:attribute:: ServerEventState.check + + A :ref:`server_event_checkres_class`, provided if the state change is + due to a server check (must be an operational change). + +.. js:attribute:: ServerEventState.cause + + Printable state change cause. Might be empty. + +.. js:attribute:: ServerEventState.new_state + + New server state due to operational or admin change. + + It is a string that can be any of the following values: + - "STOPPED": The server is down + - "STOPPING": The server is up but soft-stopping + - "STARTING": The server is warming up + - "RUNNING": The server is fully up + +.. js:attribute:: ServerEventState.old_state + + Previous server state prior to the operational or admin change. + + Can be any value described in **new_state**, but they should differ. + +.. js:attribute:: ServerEventState.requeued + + Number of connections that were requeued due to the server state change. + + For a server going DOWN: it is the number of pending server connections + that are requeued to the backend (such connections will be redispatched + to any server that is suitable according to the configured load balancing + algorithm). + + For a server doing UP: it is the number of pending connections on the + backend that may be redispatched to the server according to the load + balancing algorithm that is in use. + +.. _server_event_admin_class: + +ServerEventAdmin class +====================== + +.. js:class:: ServerEventAdmin + +This class contains additional info related to **SERVER_ADMIN** event. + +.. js:attribute:: ServerEventAdmin.cause + + Printable admin state change cause. Might be empty. + +.. js:attribute:: ServerEventAdmin.new_admin + + New server admin state due to the admin change. + + It is an array of string containing a composition of following values: + - "**MAINT**": server is in maintenance mode + - "FMAINT": server is in forced maintenance mode (MAINT is also set) + - "IMAINT": server is in inherited maintenance mode (MAINT is also set) + - "RMAINT": server is in resolve maintenance mode (MAINT is also set) + - "CMAINT": server is in config maintenance mode (MAINT is also set) + - "**DRAIN**": server is in drain mode + - "FDRAIN": server is in forced drain mode (DRAIN is also set) + - "IDRAIN": server is in inherited drain mode (DRAIN is also set) + +.. js:attribute:: ServerEventAdmin.old_admin + + Previous server admin state prior to the admin change. + + Values are presented as in **new_admin**, but they should differ. + (Comparing old and new helps to find out the change(s)) + +.. js:attribute:: ServerEventAdmin.requeued + + Same as :js:attr:`ServerEventState.requeued` but when the requeue is due to + the server administrative state change. + +.. _queue_class: + +Queue class +=========== + +.. js:class:: Queue + + This class provides a generic FIFO storage mechanism that may be shared + between multiple lua contexts to easily pass data between them, as stock + Lua doesn't provide easy methods for passing data between multiple coroutines. + + inter-task example: + +.. code-block:: lua + + -- script wide shared queue + local queue = core.queue() + + -- master task + core.register_task(function() + -- send the date every second + while true do + queue:push(os.date("%c", core.now().sec)) + core.sleep(1) + end + end) + + -- worker task + core.register_task(function() + while true do + -- print the date sent by master + print(queue:pop_wait()) + end + end) +.. + + Of course, queue may also be used as a local storage mechanism. + + Use :js:func:`core.queue` to get a new Queue object. + +.. js:function:: Queue.size(queue) + + This function returns the number of items within the Queue. + + :param class_queue queue: A :ref:`queue_class` to the current queue + +.. js:function:: Queue.push(queue, item) + + This function pushes the item (may be of any type) to the queue. + Pushed item cannot be nil or invalid, or an error will be thrown. + + :param class_queue queue: A :ref:`queue_class` to the current queue + :returns: boolean true for success and false for error + +.. js:function:: Queue.pop(queue) + + This function immediately tries to pop an item from the queue. + It returns nil of no item is available at the time of the call. + + :param class_queue queue: A :ref:`queue_class` to the current queue + :returns: the item at the top of the stack (any type) or nil if no items + +.. js:function:: Queue.pop_wait(queue) + + **context**: task + + This is an alternative to pop() that may be used within task contexts. + + The call waits for data if no item is currently available. This may be + useful when used in a while loop to prevent cpu waste. + + Note that this requires yielding, thus it is only available within contexts + that support yielding (mainly task context). + + :param class_queue queue: A :ref:`queue_class` to the current queue + :returns: the item at the top of the stack (any type) or nil in case of error + +.. _concat_class: + +Concat class +============ + +.. js:class:: Concat + + This class provides a fast way for string concatenation. The way using native + Lua concatenation like the code below is slow for some reasons. + +.. code-block:: lua + + str = "string1" + str = str .. ", string2" + str = str .. ", string3" +.. + + For each concatenation, Lua: + - allocates memory for the result, + - catenates the two string copying the strings in the new memory block, + - frees the old memory block containing the string which is no longer used. + + This process does many memory move, allocation and free. In addition, the + memory is not really freed, it is just marked as unused and waits for the + garbage collector. + + The Concat class provides an alternative way to concatenate strings. It uses + the internal Lua mechanism (it does not allocate memory), but it doesn't copy + the data more than once. + + On my computer, the following loops spends 0.2s for the Concat method and + 18.5s for the pure Lua implementation. So, the Concat class is about 1000x + faster than the embedded solution. + +.. code-block:: lua + + for j = 1, 100 do + c = core.concat() + for i = 1, 20000 do + c:add("#####") + end + end +.. + +.. code-block:: lua + + for j = 1, 100 do + c = "" + for i = 1, 20000 do + c = c .. "#####" + end + end +.. + +.. js:function:: Concat.add(concat, string) + + This function adds a string to the current concatenated string. + + :param class_concat concat: A :ref:`concat_class` which contains the currently + built string. + :param string string: A new string to concatenate to the current built + string. + +.. js:function:: Concat.dump(concat) + + This function returns the concatenated string. + + :param class_concat concat: A :ref:`concat_class` which contains the currently + built string. + :returns: the concatenated string + +.. _fetches_class: + +Fetches class +============= + +.. js:class:: Fetches + + This class contains a lot of internal HAProxy sample fetches. See the + HAProxy "configuration.txt" documentation for more information. + (chapters 7.3.2 to 7.3.6) + + .. warning:: + some sample fetches are not available in some context. These limitations + are specified in this documentation when they're useful. + + :see: :js:attr:`TXN.f` + :see: :js:attr:`TXN.sf` + + Fetches are useful to: + + * get system time, + * get environment variable, + * get random numbers, + * know backend status like the number of users in queue or the number of + connections established, + * get client information like ip source or destination, + * deal with stick tables, + * fetch established SSL information, + * fetch HTTP information like headers or method. + +.. code-block:: lua + + function action(txn) + -- Get source IP + local clientip = txn.f:src() + end +.. + +.. _converters_class: + +Converters class +================ + +.. js:class:: Converters + + This class contains a lot of internal HAProxy sample converters. See the + HAProxy documentation "configuration.txt" for more information about her + usage. Its the chapter 7.3.1. + + :see: :js:attr:`TXN.c` + :see: :js:attr:`TXN.sc` + + Converters provides stateful transformation. They are useful to: + + * convert input to base64, + * apply hash on input string (djb2, crc32, sdbm, wt6), + * format date, + * json escape, + * extract preferred language comparing two lists, + * turn to lower or upper chars, + * deal with stick tables. + +.. _channel_class: + +Channel class +============= + +.. js:class:: Channel + + **context**: action, sample-fetch, convert, filter + + HAProxy uses two buffers for the processing of the requests. The first one is + used with the request data (from the client to the server) and the second is + used for the response data (from the server to the client). + + Each buffer contains two types of data. The first type is the incoming data + waiting for a processing. The second part is the outgoing data already + processed. Usually, the incoming data is processed, after it is tagged as + outgoing data, and finally it is sent. The following functions provides tools + for manipulating these data in a buffer. + + The following diagram shows where the channel class function are applied. + + .. image:: _static/channel.png + + .. warning:: + It is not possible to read from the response in request action, and it is + not possible to read from the request channel in response action. + + .. warning:: + It is forbidden to alter the Channels buffer from HTTP contexts. So only + :js:func:`Channel.input`, :js:func:`Channel.output`, + :js:func:`Channel.may_recv`, :js:func:`Channel.is_full` and + :js:func:`Channel.is_resp` can be called from a HTTP context. + + All the functions provided by this class are available in the + **sample-fetches**, **actions** and **filters** contexts. For **filters**, + incoming data (offset and length) are relative to the filter. Some functions + may yield, but only for **actions**. Yield is not possible for + **sample-fetches**, **converters** and **filters**. + +.. js:function:: Channel.append(channel, string) + + This function copies the string **string** at the end of incoming data of the + channel buffer. The function returns the copied length on success or -1 if + data cannot be copied. + + Same that :js:func:`Channel.insert(channel, string, channel:input())`. + + :param class_channel channel: The manipulated Channel. + :param string string: The data to copy at the end of incoming data. + :returns: an integer containing the amount of bytes copied or -1. + +.. js:function:: Channel.data(channel [, offset [, length]]) + + This function returns **length** bytes of incoming data from the channel + buffer, starting at the offset **offset**. The data are not removed from the + buffer. + + By default, if no length is provided, all incoming data found, starting at the + given offset, are returned. If **length** is set to -1, the function tries to + retrieve a maximum of data and, if called by an action, it yields if + necessary. It also waits for more data if the requested length exceeds the + available amount of incoming data. Not providing an offset is the same as + setting it to 0. A positive offset is relative to the beginning of incoming + data of the channel buffer while negative offset is relative to the end. + + If there is no incoming data and the channel can't receive more data, a 'nil' + value is returned. + + :param class_channel channel: The manipulated Channel. + :param integer offset: *optional* The offset in incoming data to start to get + data. 0 by default. May be negative to be relative to the end of incoming + data. + :param integer length: *optional* The expected length of data to retrieve. All + incoming data by default. May be set to -1 to get a maximum of data. + :returns: a string containing the data found or nil. + +.. js:function:: Channel.forward(channel, length) + + This function forwards **length** bytes of data from the channel buffer. If + the requested length exceeds the available amount of incoming data, and if + called by an action, the function yields, waiting for more data to forward. It + returns the amount of data forwarded. + + :param class_channel channel: The manipulated Channel. + :param integer int: The amount of data to forward. + +.. js:function:: Channel.input(channel) + + This function returns the length of incoming data in the channel buffer. When + called by a filter, this value is relative to the filter. + + :param class_channel channel: The manipulated Channel. + :returns: an integer containing the amount of available bytes. + +.. js:function:: Channel.insert(channel, string [, offset]) + + This function copies the string **string** at the offset **offset** in + incoming data of the channel buffer. The function returns the copied length on + success or -1 if data cannot be copied. + + By default, if no offset is provided, the string is copied in front of + incoming data. A positive offset is relative to the beginning of incoming data + of the channel buffer while negative offset is relative to their end. + + :param class_channel channel: The manipulated Channel. + :param string string: The data to copy into incoming data. + :param integer offset: *optional* The offset in incoming data where to copy + data. 0 by default. May be negative to be relative to the end of incoming + data. + :returns: an integer containing the amount of bytes copied or -1. + +.. js:function:: Channel.is_full(channel) + + This function returns true if the channel buffer is full. + + :param class_channel channel: The manipulated Channel. + :returns: a boolean + +.. js:function:: Channel.is_resp(channel) + + This function returns true if the channel is the response one. + + :param class_channel channel: The manipulated Channel. + :returns: a boolean + +.. js:function:: Channel.line(channel [, offset [, length]]) + + This function parses **length** bytes of incoming data of the channel buffer, + starting at offset **offset**, and returns the first line found, including the + '\\n'. The data are not removed from the buffer. If no line is found, all + data are returned. + + By default, if no length is provided, all incoming data, starting at the given + offset, are evaluated. If **length** is set to -1, the function tries to + retrieve a maximum of data and, if called by an action, yields if + necessary. It also waits for more data if the requested length exceeds the + available amount of incoming data. Not providing an offset is the same as + setting it to 0. A positive offset is relative to the beginning of incoming + data of the channel buffer while negative offset is relative to the end. + + If there is no incoming data and the channel can't receive more data, a 'nil' + value is returned. + + :param class_channel channel: The manipulated Channel. + :param integer offset: *optional* The offset in incoming data to start to + parse data. 0 by default. May be negative to be relative to the end of + incoming data. + :param integer length: *optional* The length of data to parse. All incoming + data by default. May be set to -1 to get a maximum of data. + :returns: a string containing the line found or nil. + +.. js:function:: Channel.may_recv(channel) + + This function returns true if the channel may still receive data. + + :param class_channel channel: The manipulated Channel. + :returns: a boolean + +.. js:function:: Channel.output(channel) + + This function returns the length of outgoing data of the channel buffer. When + called by a filter, this value is relative to the filter. + + :param class_channel channel: The manipulated Channel. + :returns: an integer containing the amount of available bytes. + +.. js:function:: Channel.prepend(channel, string) + + This function copies the string **string** in front of incoming data of the + channel buffer. The function returns the copied length on success or -1 if + data cannot be copied. + + Same that :js:func:`Channel.insert(channel, string, 0)`. + + :param class_channel channel: The manipulated Channel. + :param string string: The data to copy in front of incoming data. + :returns: an integer containing the amount of bytes copied or -1. + +.. js:function:: Channel.remove(channel [, offset [, length]]) + + This function removes **length** bytes of incoming data of the channel buffer, + starting at offset **offset**. This function returns number of bytes removed + on success. + + By default, if no length is provided, all incoming data, starting at the given + offset, are removed. Not providing an offset is the same as setting it + to 0. A positive offset is relative to the beginning of incoming data of the + channel buffer while negative offset is relative to the end. + + :param class_channel channel: The manipulated Channel. + :param integer offset: *optional* The offset in incoming data where to start + to remove data. 0 by default. May be negative to be relative to the end of + incoming data. + :param integer length: *optional* The length of data to remove. All incoming + data by default. + :returns: an integer containing the amount of bytes removed. + +.. js:function:: Channel.send(channel, string) + + This function requires immediate send of the string **string**. It means the + string is copied at the beginning of incoming data of the channel buffer and + immediately forwarded. Unless if the connection is close, and if called by an + action, this function yields to copy and forward all the string. + + :param class_channel channel: The manipulated Channel. + :param string string: The data to send. + :returns: an integer containing the amount of bytes copied or -1. + +.. js:function:: Channel.set(channel, string [, offset [, length]]) + + This function replaces **length** bytes of incoming data of the channel + buffer, starting at offset **offset**, by the string **string**. The function + returns the copied length on success or -1 if data cannot be copied. + + By default, if no length is provided, all incoming data, starting at the given + offset, are replaced. Not providing an offset is the same as setting it + to 0. A positive offset is relative to the beginning of incoming data of the + channel buffer while negative offset is relative to the end. + + :param class_channel channel: The manipulated Channel. + :param string string: The data to copy into incoming data. + :param integer offset: *optional* The offset in incoming data where to start + the data replacement. 0 by default. May be negative to be relative to the + end of incoming data. + :param integer length: *optional* The length of data to replace. All incoming + data by default. + :returns: an integer containing the amount of bytes copied or -1. + +.. js:function:: Channel.dup(channel) + + **DEPRECATED** + + This function returns all incoming data found in the channel buffer. The data + are not removed from the buffer and can be reprocessed later. + + If there is no incoming data and the channel can't receive more data, a 'nil' + value is returned. + + :param class_channel channel: The manipulated Channel. + :returns: a string containing all data found or nil. + + .. warning:: + This function is deprecated. :js:func:`Channel.data()` must be used + instead. + +.. js:function:: Channel.get(channel) + + **DEPRECATED** + + This function returns all incoming data found in the channel buffer and remove + them from the buffer. + + If there is no incoming data and the channel can't receive more data, a 'nil' + value is returned. + + :param class_channel channel: The manipulated Channel. + :returns: a string containing all the data found or nil. + + .. warning:: + This function is deprecated. :js:func:`Channel.data()` must be used to + retrieve data followed by a call to :js:func:`Channel:remove()` to remove + data. + + .. code-block:: lua + + local data = chn:data() + chn:remove(0, data:len()) + + .. + +.. js:function:: Channel.getline(channel) + + **DEPRECATED** + + This function returns the first line found in incoming data of the channel + buffer, including the '\\n'. The returned data are removed from the buffer. If + no line is found, and if called by an action, this function yields to wait for + more data, except if the channel can't receive more data. In this case all + data are returned. + + If there is no incoming data and the channel can't receive more data, a 'nil' + value is returned. + + :param class_channel channel: The manipulated Channel. + :returns: a string containing the line found or nil. + + .. warning:: + This function is deprecated. :js:func:`Channel.line()` must be used to + retrieve a line followed by a call to :js:func:`Channel:remove()` to remove + data. + + .. code-block:: lua + + local line = chn:line(0, -1) + chn:remove(0, line:len()) + + .. + +.. js:function:: Channel.get_in_len(channel) + + **DEPRECATED** + + This function returns the length of the input part of the buffer. When called + by a filter, this value is relative to the filter. + + :param class_channel channel: The manipulated Channel. + :returns: an integer containing the amount of available bytes. + + .. warning:: + This function is deprecated. :js:func:`Channel.input()` must be used + instead. + +.. js:function:: Channel.get_out_len(channel) + + **DEPRECATED** + + This function returns the length of the output part of the buffer. When called + by a filter, this value is relative to the filter. + + :param class_channel channel: The manipulated Channel. + :returns: an integer containing the amount of available bytes. + + .. warning:: + This function is deprecated. :js:func:`Channel.output()` must be used + instead. + +.. _http_class: + +HTTP class +========== + +.. js:class:: HTTP + + This class contain all the HTTP manipulation functions. + +.. js:function:: HTTP.req_get_headers(http) + + Returns a table containing all the request headers. + + :param class_http http: The related http object. + :returns: table of headers. + :see: :js:func:`HTTP.res_get_headers` + + This is the form of the returned table: + +.. code-block:: lua + + HTTP:req_get_headers()['<header-name>'][<header-index>] = "<header-value>" + + local hdr = HTTP:req_get_headers() + hdr["host"][0] = "www.test.com" + hdr["accept"][0] = "audio/basic q=1" + hdr["accept"][1] = "audio/*, q=0.2" + hdr["accept"][2] = "*/*, q=0.1" +.. + +.. js:function:: HTTP.res_get_headers(http) + + Returns a table containing all the response headers. + + :param class_http http: The related http object. + :returns: table of headers. + :see: :js:func:`HTTP.req_get_headers` + + This is the form of the returned table: + +.. code-block:: lua + + HTTP:res_get_headers()['<header-name>'][<header-index>] = "<header-value>" + + local hdr = HTTP:req_get_headers() + hdr["host"][0] = "www.test.com" + hdr["accept"][0] = "audio/basic q=1" + hdr["accept"][1] = "audio/*, q=0.2" + hdr["accept"][2] = "*.*, q=0.1" +.. + +.. js:function:: HTTP.req_add_header(http, name, value) + + Appends a HTTP header field in the request whose name is + specified in "name" and whose value is defined in "value". + + :param class_http http: The related http object. + :param string name: The header name. + :param string value: The header value. + :see: :js:func:`HTTP.res_add_header` + +.. js:function:: HTTP.res_add_header(http, name, value) + + Appends a HTTP header field in the response whose name is + specified in "name" and whose value is defined in "value". + + :param class_http http: The related http object. + :param string name: The header name. + :param string value: The header value. + :see: :js:func:`HTTP.req_add_header` + +.. js:function:: HTTP.req_del_header(http, name) + + Removes all HTTP header fields in the request whose name is + specified in "name". + + :param class_http http: The related http object. + :param string name: The header name. + :see: :js:func:`HTTP.res_del_header` + +.. js:function:: HTTP.res_del_header(http, name) + + Removes all HTTP header fields in the response whose name is + specified in "name". + + :param class_http http: The related http object. + :param string name: The header name. + :see: :js:func:`HTTP.req_del_header` + +.. js:function:: HTTP.req_set_header(http, name, value) + + This variable replace all occurrence of all header "name", by only + one containing the "value". + + :param class_http http: The related http object. + :param string name: The header name. + :param string value: The header value. + :see: :js:func:`HTTP.res_set_header` + + This function does the same work as the following code: + +.. code-block:: lua + + function fcn(txn) + TXN.http:req_del_header("header") + TXN.http:req_add_header("header", "value") + end +.. + +.. js:function:: HTTP.res_set_header(http, name, value) + + This function replaces all occurrence of all header "name", by only + one containing the "value". + + :param class_http http: The related http object. + :param string name: The header name. + :param string value: The header value. + :see: :js:func:`HTTP.req_rep_header()` + +.. js:function:: HTTP.req_rep_header(http, name, regex, replace) + + Matches the regular expression in all occurrences of header field "name" + according to "regex", and replaces them with the "replace" argument. The + replacement value can contain back references like \1, \2, ... This + function works with the request. + + :param class_http http: The related http object. + :param string name: The header name. + :param string regex: The match regular expression. + :param string replace: The replacement value. + :see: :js:func:`HTTP.res_rep_header()` + +.. js:function:: HTTP.res_rep_header(http, name, regex, string) + + Matches the regular expression in all occurrences of header field "name" + according to "regex", and replaces them with the "replace" argument. The + replacement value can contain back references like \1, \2, ... This + function works with the request. + + :param class_http http: The related http object. + :param string name: The header name. + :param string regex: The match regular expression. + :param string replace: The replacement value. + :see: :js:func:`HTTP.req_rep_header()` + +.. js:function:: HTTP.req_set_method(http, method) + + Rewrites the request method with the parameter "method". + + :param class_http http: The related http object. + :param string method: The new method. + +.. js:function:: HTTP.req_set_path(http, path) + + Rewrites the request path with the "path" parameter. + + :param class_http http: The related http object. + :param string path: The new path. + +.. js:function:: HTTP.req_set_query(http, query) + + Rewrites the request's query string which appears after the first question + mark ("?") with the parameter "query". + + :param class_http http: The related http object. + :param string query: The new query. + +.. js:function:: HTTP.req_set_uri(http, uri) + + Rewrites the request URI with the parameter "uri". + + :param class_http http: The related http object. + :param string uri: The new uri. + +.. js:function:: HTTP.res_set_status(http, status [, reason]) + + Rewrites the response status code with the parameter "code". + + If no custom reason is provided, it will be generated from the status. + + :param class_http http: The related http object. + :param integer status: The new response status code. + :param string reason: The new response reason (optional). + +.. _httpclient_class: + +HTTPClient class +================ + +.. js:class:: HTTPClient + + The httpclient class allows issue of outbound HTTP requests through a simple + API without the knowledge of HAProxy internals. + +.. js:function:: HTTPClient.get(httpclient, request) +.. js:function:: HTTPClient.head(httpclient, request) +.. js:function:: HTTPClient.put(httpclient, request) +.. js:function:: HTTPClient.post(httpclient, request) +.. js:function:: HTTPClient.delete(httpclient, request) + + Send a HTTP request and wait for a response. GET, HEAD PUT, POST and DELETE + methods can be used. + The HTTPClient will send asynchronously the data and is able to send and + receive more than HAProxy bufsize. + + The HTTPClient interface is not able to decompress responses, it is not + recommended to send an Accept-Encoding in the request so the response is + received uncompressed. + + :param class httpclient: Is the manipulated HTTPClient. + :param table request: Is a table containing the parameters of the request + that will be send. + :param string request.url: Is a mandatory parameter for the request that + contains the URL. + :param string request.body: Is an optional parameter for the request that + contains the body to send. + :param table request.headers: Is an optional parameter for the request that + contains the headers to send. + :param string request.dst: Is an optional parameter for the destination in + haproxy address format. + :param integer request.timeout: Optional timeout parameter, set a + "timeout server" on the connections. + :returns: Lua table containing the response + + +.. code-block:: lua + + local httpclient = core.httpclient() + local response = httpclient:post{url="http://127.0.0.1", body=body, dst="unix@/var/run/http.sock"} + +.. + +.. code-block:: lua + + response = { + status = 400, + reason = "Bad request", + headers = { + ["content-type"] = { "text/html" }, + ["cache-control"] = { "no-cache", "no-store" }, + }, + body = "<html><body><h1>invalid request<h1></body></html>", + } +.. + + +.. _txn_class: + +TXN class +========= + +.. js:class:: TXN + + The txn class contain all the functions relative to the http or tcp + transaction (Note than a tcp stream is the same than a tcp transaction, but + a HTTP transaction is not the same than a tcp stream). + + The usage of this class permits to retrieve data from the requests, alter it + and forward it. + + All the functions provided by this class are available in the context + **sample-fetches**, **actions** and **filters**. + +.. js:attribute:: TXN.c + + :returns: An :ref:`converters_class`. + + This attribute contains a Converters class object. + +.. js:attribute:: TXN.sc + + :returns: An :ref:`converters_class`. + + This attribute contains a Converters class object. The functions of + this object returns always a string. + +.. js:attribute:: TXN.f + + :returns: An :ref:`fetches_class`. + + This attribute contains a Fetches class object. + +.. js:attribute:: TXN.sf + + :returns: An :ref:`fetches_class`. + + This attribute contains a Fetches class object. The functions of + this object returns always a string. + +.. js:attribute:: TXN.req + + :returns: An :ref:`channel_class`. + + This attribute contains a channel class object for the request buffer. + +.. js:attribute:: TXN.res + + :returns: An :ref:`channel_class`. + + This attribute contains a channel class object for the response buffer. + +.. js:attribute:: TXN.http + + :returns: An :ref:`http_class`. + + This attribute contains a HTTP class object. It is available only if the + proxy has the "mode http" enabled. + +.. js:attribute:: TXN.http_req + + :returns: An :ref:`httpmessage_class`. + + This attribute contains the request HTTPMessage class object. It is available + only if the proxy has the "mode http" enabled and only in the **filters** + context. + +.. js:attribute:: TXN.http_res + + :returns: An :ref:`httpmessage_class`. + + This attribute contains the response HTTPMessage class object. It is available + only if the proxy has the "mode http" enabled and only in the **filters** + context. + +.. js:function:: TXN.log(TXN, loglevel, msg) + + This function sends a log. The log is sent, according with the HAProxy + configuration file, to the loggers relevant to the current context and/or + to stderr if it is allowed. + + The exact behaviour depends on tune.lua.log.loggers and tune.lua.log.stderr. + + :param class_txn txn: The class txn object containing the data. + :param integer loglevel: Is the log level associated with the message. It is + a number between 0 and 7. + :param string msg: The log content. + :see: :js:attr:`core.emerg`, :js:attr:`core.alert`, :js:attr:`core.crit`, + :js:attr:`core.err`, :js:attr:`core.warning`, :js:attr:`core.notice`, + :js:attr:`core.info`, :js:attr:`core.debug` (log level definitions) + :see: :js:func:`TXN.deflog` + :see: :js:func:`TXN.Debug` + :see: :js:func:`TXN.Info` + :see: :js:func:`TXN.Warning` + :see: :js:func:`TXN.Alert` + +.. js:function:: TXN.deflog(TXN, msg) + + Sends a log line with the default loglevel for the proxy associated with the + transaction. + + :param class_txn txn: The class txn object containing the data. + :param string msg: The log content. + :see: :js:func:`TXN.log` + +.. js:function:: TXN.Debug(txn, msg) + + :param class_txn txn: The class txn object containing the data. + :param string msg: The log content. + :see: :js:func:`TXN.log` + + Does the same job as: + +.. code-block:: lua + + function Debug(txn, msg) + TXN.log(txn, core.debug, msg) + end +.. + +.. js:function:: TXN.Info(txn, msg) + + :param class_txn txn: The class txn object containing the data. + :param string msg: The log content. + :see: :js:func:`TXN.log` + + Does the same job as: + +.. code-block:: lua + + function Info(txn, msg) + TXN.log(txn, core.info, msg) + end +.. + +.. js:function:: TXN.Warning(txn, msg) + + :param class_txn txn: The class txn object containing the data. + :param string msg: The log content. + :see: :js:func:`TXN.log` + + Does the same job as: + +.. code-block:: lua + + function Warning(txn, msg) + TXN.log(txn, core.warning, msg) + end +.. + +.. js:function:: TXN.Alert(txn, msg) + + :param class_txn txn: The class txn object containing the data. + :param string msg: The log content. + :see: :js:func:`TXN.log` + + Does the same job as: + +.. code-block:: lua + + function Alert(txn, msg) + TXN.log(txn, core.alert, msg) + end +.. + +.. js:function:: TXN.get_priv(txn) + + Return Lua data stored in the current transaction (with the `TXN.set_priv()`) + function. If no data are stored, it returns a nil value. + + :param class_txn txn: The class txn object containing the data. + :returns: the opaque data previously stored, or nil if nothing is + available. + +.. js:function:: TXN.set_priv(txn, data) + + Store any data in the current HAProxy transaction. This action replaces the + old stored data. + + :param class_txn txn: The class txn object containing the data. + :param opaque data: The data which is stored in the transaction. + +.. js:function:: TXN.set_var(TXN, var, value[, ifexist]) + + Converts a Lua type in a HAProxy type and store it in a variable <var>. + + :param class_txn txn: The class txn object containing the data. + :param string var: The variable name according with the HAProxy variable + syntax. + :param type value: The value associated to the variable. The type can be + string or integer. + :param boolean ifexist: If this parameter is set to true the variable will + only be set if it was defined elsewhere (i.e. used within the configuration). + For global variables (using the "proc" scope), they will only be updated and + never created. It is highly recommended to always set this to true. + +.. js:function:: TXN.unset_var(TXN, var) + + Unset the variable <var>. + + :param class_txn txn: The class txn object containing the data. + :param string var: The variable name according with the HAProxy variable + syntax. + +.. js:function:: TXN.get_var(TXN, var) + + Returns data stored in the variable <var> converter in Lua type. + + :param class_txn txn: The class txn object containing the data. + :param string var: The variable name according with the HAProxy variable + syntax. + +.. js:function:: TXN.reply([reply]) + + Return a new reply object + + :param table reply: A table containing info to initialize the reply fields. + :returns: A :ref:`reply_class` object. + + The table used to initialized the reply object may contain following entries : + + * status : The reply status code. the code 200 is used by default. + * reason : The reply reason. The reason corresponding to the status code is + used by default. + * headers : A list of headers, indexed by header name. Empty by default. For + a given name, multiple values are possible, stored in an ordered list. + * body : The reply body, empty by default. + +.. code-block:: lua + + local reply = txn:reply{ + status = 400, + reason = "Bad request", + headers = { + ["content-type"] = { "text/html" }, + ["cache-control"] = {"no-cache", "no-store" } + }, + body = "<html><body><h1>invalid request<h1></body></html>" + } +.. + :see: :js:class:`Reply` + +.. js:function:: TXN.done(txn[, reply]) + + This function terminates processing of the transaction and the associated + session and optionally reply to the client for HTTP sessions. + + :param class_txn txn: The class txn object containing the data. + :param class_reply reply: The class reply object to return to the client. + + This functions can be used when a critical error is detected or to terminate + processing after some data have been returned to the client (eg: a redirect). + To do so, a reply may be provided. This object is optional and may contain a + status code, a reason, a header list and a body. All these fields are + optional. When not provided, the default values are used. By default, with an + empty reply object, an empty HTTP 200 response is returned to the client. If + no reply object is provided, the transaction is terminated without any + reply. If a reply object is provided, it must not exceed the buffer size once + converted into the internal HTTP representation. Because for now there is no + easy way to be sure it fits, it is probably better to keep it reasonably + small. + + The reply object may be fully created in lua or the class Reply may be used to + create it. + +.. code-block:: lua + + local reply = txn:reply() + reply:set_status(400, "Bad request") + reply:add_header("content-type", "text/html") + reply:add_header("cache-control", "no-cache") + reply:add_header("cache-control", "no-store") + reply:set_body("<html><body><h1>invalid request<h1></body></html>") + txn:done(reply) +.. + +.. code-block:: lua + + txn:done{ + status = 400, + reason = "Bad request", + headers = { + ["content-type"] = { "text/html" }, + ["cache-control"] = { "no-cache", "no-store" }, + }, + body = "<html><body><h1>invalid request<h1></body></html>" + } +.. + + .. warning:: + It does not make sense to call this function from sample-fetches. In this + case the behavior is the same than core.done(): it finishes the Lua + execution. The transaction is really aborted only from an action registered + function. + + :see: :js:func:`TXN.reply`, :js:class:`Reply` + +.. js:function:: TXN.set_loglevel(txn, loglevel) + + Is used to change the log level of the current request. The "loglevel" must + be an integer between 0 and 7. + + :param class_txn txn: The class txn object containing the data. + :param integer loglevel: The required log level. This variable can be one of + :see: :js:attr:`core.emerg`, :js:attr:`core.alert`, :js:attr:`core.crit`, + :js:attr:`core.err`, :js:attr:`core.warning`, :js:attr:`core.notice`, + :js:attr:`core.info`, :js:attr:`core.debug` (log level definitions) + +.. js:function:: TXN.set_tos(txn, tos) + + Is used to set the TOS or DSCP field value of packets sent to the client to + the value passed in "tos" on platforms which support this. + + :param class_txn txn: The class txn object containing the data. + :param integer tos: The new TOS os DSCP. + +.. js:function:: TXN.set_mark(txn, mark) + + Is used to set the Netfilter MARK on all packets sent to the client to the + value passed in "mark" on platforms which support it. + + :param class_txn txn: The class txn object containing the data. + :param integer mark: The mark value. + +.. js:function:: TXN.set_priority_class(txn, prio) + + This function adjusts the priority class of the transaction. The value should + be within the range -2047..2047. Values outside this range will be + truncated. + + See the HAProxy configuration.txt file keyword "http-request" action + "set-priority-class" for details. + +.. js:function:: TXN.set_priority_offset(txn, prio) + + This function adjusts the priority offset of the transaction. The value + should be within the range -524287..524287. Values outside this range will be + truncated. + + See the HAProxy configuration.txt file keyword "http-request" action + "set-priority-offset" for details. + +.. _reply_class: + +Reply class +============ + +.. js:class:: Reply + + **context**: action + + This class represents a HTTP response message. It provides some methods to + enrich it. Once converted into the internal HTTP representation, the response + message must not exceed the buffer size. Because for now there is no + easy way to be sure it fits, it is probably better to keep it reasonably + small. + + See tune.bufsize in the configuration manual for details. + +.. code-block:: lua + + local reply = txn:reply({status = 400}) -- default HTTP 400 reason-phase used + reply:add_header("content-type", "text/html") + reply:add_header("cache-control", "no-cache") + reply:add_header("cache-control", "no-store") + reply:set_body("<html><body><h1>invalid request<h1></body></html>") +.. + + :see: :js:func:`TXN.reply` + +.. js:attribute:: Reply.status + + The reply status code. By default, the status code is set to 200. + + :returns: integer + +.. js:attribute:: Reply.reason + + The reason string describing the status code. + + :returns: string + +.. js:attribute:: Reply.headers + + A table indexing all reply headers by name. To each name is associated an + ordered list of values. + + :returns: Lua table + +.. code-block:: lua + + { + ["content-type"] = { "text/html" }, + ["cache-control"] = {"no-cache", "no-store" }, + x_header_name = { "value1", "value2", ... } + ... + } +.. + +.. js:attribute:: Reply.body + + The reply payload. + + :returns: string + +.. js:function:: Reply.set_status(REPLY, status[, reason]) + + Set the reply status code and optionally the reason-phrase. If the reason is + not provided, the default reason corresponding to the status code is used. + + :param class_reply reply: The related Reply object. + :param integer status: The reply status code. + :param string reason: The reply status reason (optional). + +.. js:function:: Reply.add_header(REPLY, name, value) + + Add a header to the reply object. If the header does not already exist, a new + entry is created with its name as index and a one-element list containing its + value as value. Otherwise, the header value is appended to the ordered list of + values associated to the header name. + + :param class_reply reply: The related Reply object. + :param string name: The header field name. + :param string value: The header field value. + +.. js:function:: Reply.del_header(REPLY, name) + + Remove all occurrences of a header name from the reply object. + + :param class_reply reply: The related Reply object. + :param string name: The header field name. + +.. js:function:: Reply.set_body(REPLY, body) + + Set the reply payload. + + :param class_reply reply: The related Reply object. + :param string body: The reply payload. + +.. _socket_class: + +Socket class +============ + +.. js:class:: Socket + + This class must be compatible with the Lua Socket class. Only the 'client' + functions are available. See the Lua Socket documentation: + + `http://w3.impa.br/~diego/software/luasocket/tcp.html + <http://w3.impa.br/~diego/software/luasocket/tcp.html>`_ + +.. js:function:: Socket.close(socket) + + Closes a TCP object. The internal socket used by the object is closed and the + local address to which the object was bound is made available to other + applications. No further operations (except for further calls to the close + method) are allowed on a closed Socket. + + :param class_socket socket: Is the manipulated Socket. + + Note: It is important to close all used sockets once they are not needed, + since, in many systems, each socket uses a file descriptor, which are limited + system resources. Garbage-collected objects are automatically closed before + destruction, though. + +.. js:function:: Socket.connect(socket, address[, port]) + + Attempts to connect a socket object to a remote host. + + + In case of error, the method returns nil followed by a string describing the + error. In case of success, the method returns 1. + + :param class_socket socket: Is the manipulated Socket. + :param string address: can be an IP address or a host name. See below for more + information. + :param integer port: must be an integer number in the range [1..64K]. + :returns: 1 or nil. + + An address field extension permits to use the connect() function to connect to + other stream than TCP. The syntax containing a simpleipv4 or ipv6 address is + the basically expected format. This format requires the port. + + Other format accepted are a socket path like "/socket/path", it permits to + connect to a socket. Abstract namespaces are supported with the prefix + "abns@", and finally a file descriptor can be passed with the prefix "fd@". + The prefix "ipv4@", "ipv6@" and "unix@" are also supported. The port can be + passed int the string. The syntax "127.0.0.1:1234" is valid. In this case, the + parameter *port* must not be set. + +.. js:function:: Socket.connect_ssl(socket, address, port) + + Same behavior than the function socket:connect, but uses SSL. + + :param class_socket socket: Is the manipulated Socket. + :returns: 1 or nil. + +.. js:function:: Socket.getpeername(socket) + + Returns information about the remote side of a connected client object. + + Returns a string with the IP address of the peer, followed by the port number + that peer is using for the connection. In case of error, the method returns + nil. + + :param class_socket socket: Is the manipulated Socket. + :returns: a string containing the server information. + +.. js:function:: Socket.getsockname(socket) + + Returns the local address information associated to the object. + + The method returns a string with local IP address and a number with the port. + In case of error, the method returns nil. + + :param class_socket socket: Is the manipulated Socket. + :returns: a string containing the client information. + +.. js:function:: Socket.receive(socket, [pattern [, prefix]]) + + Reads data from a client object, according to the specified read pattern. + Patterns follow the Lua file I/O format, and the difference in performance + between all patterns is negligible. + + :param class_socket socket: Is the manipulated Socket. + :param string|integer pattern: Describe what is required (see below). + :param string prefix: A string which will be prefix the returned data. + :returns: a string containing the required data or nil. + + Pattern can be any of the following: + + * **`*a`**: reads from the socket until the connection is closed. No + end-of-line translation is performed; + + * **`*l`**: reads a line of text from the Socket. The line is terminated by a + LF character (ASCII 10), optionally preceded by a CR character + (ASCII 13). The CR and LF characters are not included in the + returned line. In fact, all CR characters are ignored by the + pattern. This is the default pattern. + + * **number**: causes the method to read a specified number of bytes from the + Socket. Prefix is an optional string to be concatenated to the + beginning of any received data before return. + + * **empty**: If the pattern is left empty, the default option is `*l`. + + If successful, the method returns the received pattern. In case of error, the + method returns nil followed by an error message which can be the string + 'closed' in case the connection was closed before the transmission was + completed or the string 'timeout' in case there was a timeout during the + operation. Also, after the error message, the function returns the partial + result of the transmission. + + Important note: This function was changed severely. It used to support + multiple patterns (but I have never seen this feature used) and now it + doesn't anymore. Partial results used to be returned in the same way as + successful results. This last feature violated the idea that all functions + should return nil on error. Thus it was changed too. + +.. js:function:: Socket.send(socket, data [, start [, end ]]) + + Sends data through client object. + + :param class_socket socket: Is the manipulated Socket. + :param string data: The data that will be sent. + :param integer start: The start position in the buffer of the data which will + be sent. + :param integer end: The end position in the buffer of the data which will + be sent. + :returns: see below. + + Data is the string to be sent. The optional arguments i and j work exactly + like the standard string.sub Lua function to allow the selection of a + substring to be sent. + + If successful, the method returns the index of the last byte within [start, + end] that has been sent. Notice that, if start is 1 or absent, this is + effectively the total number of bytes sent. In case of error, the method + returns nil, followed by an error message, followed by the index of the last + byte within [start, end] that has been sent. You might want to try again from + the byte following that. The error message can be 'closed' in case the + connection was closed before the transmission was completed or the string + 'timeout' in case there was a timeout during the operation. + + Note: Output is not buffered. For small strings, it is always better to + concatenate them in Lua (with the '..' operator) and send the result in one + call instead of calling the method several times. + +.. js:function:: Socket.setoption(socket, option [, value]) + + Just implemented for compatibility, this cal does nothing. + +.. js:function:: Socket.settimeout(socket, value [, mode]) + + Changes the timeout values for the object. All I/O operations are blocking. + That is, any call to the methods send, receive, and accept will block + indefinitely, until the operation completes. The settimeout method defines a + limit on the amount of time the I/O methods can block. When a timeout time + has elapsed, the affected methods give up and fail with an error code. + + The amount of time to wait is specified as the value parameter, in seconds. + + The timeout modes are not implemented, the only settable timeout is the + inactivity time waiting for complete the internal buffer send or waiting for + receive data. + + :param class_socket socket: Is the manipulated Socket. + :param float value: The timeout value. Use floating point to specify + milliseconds. + +.. _regex_class: + +Regex class +=========== + +.. js:class:: Regex + + This class allows the usage of HAProxy regexes because classic lua doesn't + provides regexes. This class inherits the HAProxy compilation options, so the + regexes can be libc regex, pcre regex or pcre JIT regex. + + The expression matching number is limited to 20 per regex. The only available + option is case sensitive. + + Because regexes compilation is a heavy process, it is better to define all + your regexes in the **body context** and use it during the runtime. + +.. code-block:: lua + + -- Create the regex + st, regex = Regex.new("needle (..) (...)", true); + + -- Check compilation errors + if st == false then + print "error: " .. regex + end + + -- Match the regexes + print(regex:exec("Looking for a needle in the haystack")) -- true + print(regex:exec("Lokking for a cat in the haystack")) -- false + + -- Extract words + st, list = regex:match("Looking for a needle in the haystack") + print(st) -- true + print(list[1]) -- needle in the + print(list[2]) -- in + print(list[3]) -- the + +.. js:function:: Regex.new(regex, case_sensitive) + + Create and compile a regex. + + :param string regex: The regular expression according with the libc or pcre + standard + :param boolean case_sensitive: Match is case sensitive or not. + :returns: boolean status and :ref:`regex_class` or string containing fail + reason. + +.. js:function:: Regex.exec(regex, str) + + Execute the regex. + + :param class_regex regex: A :ref:`regex_class` object. + :param string str: The input string will be compared with the compiled regex. + :returns: a boolean status according with the match result. + +.. js:function:: Regex.match(regex, str) + + Execute the regex and return matched expressions. + + :param class_map map: A :ref:`regex_class` object. + :param string str: The input string will be compared with the compiled regex. + :returns: a boolean status according with the match result, and + a table containing all the string matched in order of declaration. + +.. _map_class: + +Map class +========= + +.. js:class:: Map + + This class permits to do some lookups in HAProxy maps. The declared maps can + be modified during the runtime through the HAProxy management socket. + +.. code-block:: lua + + default = "usa" + + -- Create and load map + geo = Map.new("geo.map", Map._ip); + + -- Create new fetch that returns the user country + core.register_fetches("country", function(txn) + local src; + local loc; + + src = txn.f:fhdr("x-forwarded-for"); + if (src == nil) then + src = txn.f:src() + if (src == nil) then + return default; + end + end + + -- Perform lookup + loc = geo:lookup(src); + + if (loc == nil) then + return default; + end + + return loc; + end); + +.. js:attribute:: Map._int + + See the HAProxy configuration.txt file, chapter "Using ACLs and fetching + samples" and subchapter "ACL basics" to understand this pattern matching + method. + + Note that :js:attr:`Map.int` is also available for compatibility. + +.. js:attribute:: Map._ip + + See the HAProxy configuration.txt file, chapter "Using ACLs and fetching + samples" and subchapter "ACL basics" to understand this pattern matching + method. + + Note that :js:attr:`Map.ip` is also available for compatibility. + +.. js:attribute:: Map._str + + See the HAProxy configuration.txt file, chapter "Using ACLs and fetching + samples" and subchapter "ACL basics" to understand this pattern matching + method. + + Note that :js:attr:`Map.str` is also available for compatibility. + +.. js:attribute:: Map._beg + + See the HAProxy configuration.txt file, chapter "Using ACLs and fetching + samples" and subchapter "ACL basics" to understand this pattern matching + method. + + Note that :js:attr:`Map.beg` is also available for compatibility. + +.. js:attribute:: Map._sub + + See the HAProxy configuration.txt file, chapter "Using ACLs and fetching + samples" and subchapter "ACL basics" to understand this pattern matching + method. + + Note that :js:attr:`Map.sub` is also available for compatibility. + +.. js:attribute:: Map._dir + + See the HAProxy configuration.txt file, chapter "Using ACLs and fetching + samples" and subchapter "ACL basics" to understand this pattern matching + method. + + Note that :js:attr:`Map.dir` is also available for compatibility. + +.. js:attribute:: Map._dom + + See the HAProxy configuration.txt file, chapter "Using ACLs and fetching + samples" and subchapter "ACL basics" to understand this pattern matching + method. + + Note that :js:attr:`Map.dom` is also available for compatibility. + +.. js:attribute:: Map._end + + See the HAProxy configuration.txt file, chapter "Using ACLs and fetching + samples" and subchapter "ACL basics" to understand this pattern matching + method. + +.. js:attribute:: Map._reg + + See the HAProxy configuration.txt file, chapter "Using ACLs and fetching + samples" and subchapter "ACL basics" to understand this pattern matching + method. + + Note that :js:attr:`Map.reg` is also available for compatibility. + + +.. js:function:: Map.new(file, method) + + Creates and load a map. + + :param string file: Is the file containing the map. + :param integer method: Is the map pattern matching method. See the attributes + of the Map class. + :returns: a class Map object. + :see: The Map attributes: :js:attr:`Map._int`, :js:attr:`Map._ip`, + :js:attr:`Map._str`, :js:attr:`Map._beg`, :js:attr:`Map._sub`, + :js:attr:`Map._dir`, :js:attr:`Map._dom`, :js:attr:`Map._end` and + :js:attr:`Map._reg`. + +.. js:function:: Map.lookup(map, str) + + Perform a lookup in a map. + + :param class_map map: Is the class Map object. + :param string str: Is the string used as key. + :returns: a string containing the result or nil if no match. + +.. js:function:: Map.slookup(map, str) + + Perform a lookup in a map. + + :param class_map map: Is the class Map object. + :param string str: Is the string used as key. + :returns: a string containing the result or empty string if no match. + +.. _applethttp_class: + +AppletHTTP class +================ + +.. js:class:: AppletHTTP + + This class is used with applets that requires the 'http' mode. The http applet + can be registered with the *core.register_service()* function. They are used + for processing an http request like a server in back of HAProxy. + + This is an hello world sample code: + +.. code-block:: lua + + core.register_service("hello-world", "http", function(applet) + local response = "Hello World !" + applet:set_status(200) + applet:add_header("content-length", string.len(response)) + applet:add_header("content-type", "text/plain") + applet:start_response() + applet:send(response) + end) + +.. js:attribute:: AppletHTTP.c + + :returns: A :ref:`converters_class` + + This attribute contains a Converters class object. + +.. js:attribute:: AppletHTTP.sc + + :returns: A :ref:`converters_class` + + This attribute contains a Converters class object. The + functions of this object always return a string. + +.. js:attribute:: AppletHTTP.f + + :returns: A :ref:`fetches_class` + + This attribute contains a Fetches class object. Note that the + applet execution place cannot access to a valid HAProxy core HTTP + transaction, so some sample fetches related to the HTTP dependent + values (hdr, path, ...) are not available. + +.. js:attribute:: AppletHTTP.sf + + :returns: A :ref:`fetches_class` + + This attribute contains a Fetches class object. The functions of + this object always return a string. Note that the applet + execution place cannot access to a valid HAProxy core HTTP + transaction, so some sample fetches related to the HTTP dependent + values (hdr, path, ...) are not available. + +.. js:attribute:: AppletHTTP.method + + :returns: string + + The attribute method returns a string containing the HTTP + method. + +.. js:attribute:: AppletHTTP.version + + :returns: string + + The attribute version, returns a string containing the HTTP + request version. + +.. js:attribute:: AppletHTTP.path + + :returns: string + + The attribute path returns a string containing the HTTP + request path. + +.. js:attribute:: AppletHTTP.qs + + :returns: string + + The attribute qs returns a string containing the HTTP + request query string. + +.. js:attribute:: AppletHTTP.length + + :returns: integer + + The attribute length returns an integer containing the HTTP + body length. + +.. js:attribute:: AppletHTTP.headers + + :returns: table + + The attribute headers returns a table containing the HTTP + headers. The header names are always in lower case. As the header name can be + encountered more than once in each request, the value is indexed with 0 as + first index value. The table has this form: + +.. code-block:: lua + + AppletHTTP.headers['<header-name>'][<header-index>] = "<header-value>" + + AppletHTTP.headers["host"][0] = "www.test.com" + AppletHTTP.headers["accept"][0] = "audio/basic q=1" + AppletHTTP.headers["accept"][1] = "audio/*, q=0.2" + AppletHTTP.headers["accept"][2] = "*/*, q=0.1" +.. + +.. js:function:: AppletHTTP.set_status(applet, code [, reason]) + + This function sets the HTTP status code for the response. The allowed code are + from 100 to 599. + + :param class_AppletHTTP applet: An :ref:`applethttp_class` + :param integer code: the status code returned to the client. + :param string reason: the status reason returned to the client (optional). + +.. js:function:: AppletHTTP.add_header(applet, name, value) + + This function adds a header in the response. Duplicated headers are not + collapsed. The special header *content-length* is used to determinate the + response length. If it does not exist, a *transfer-encoding: chunked* is set, + and all the write from the function *AppletHTTP:send()* become a chunk. + + :param class_AppletHTTP applet: An :ref:`applethttp_class` + :param string name: the header name + :param string value: the header value + +.. js:function:: AppletHTTP.start_response(applet) + + This function indicates to the HTTP engine that it can process and send the + response headers. After this called we cannot add headers to the response; We + cannot use the *AppletHTTP:send()* function if the + *AppletHTTP:start_response()* is not called. + + :param class_AppletHTTP applet: An :ref:`applethttp_class` + +.. js:function:: AppletHTTP.getline(applet) + + This function returns a string containing one line from the http body. If the + data returned doesn't contains a final '\\n' its assumed than its the last + available data before the end of stream. + + :param class_AppletHTTP applet: An :ref:`applethttp_class` + :returns: a string. The string can be empty if we reach the end of the stream. + +.. js:function:: AppletHTTP.receive(applet, [size]) + + Reads data from the HTTP body, according to the specified read *size*. If the + *size* is missing, the function tries to read all the content of the stream + until the end. If the *size* is bigger than the http body, it returns the + amount of data available. + + :param class_AppletHTTP applet: An :ref:`applethttp_class` + :param integer size: the required read size. + :returns: always return a string,the string can be empty is the connection is + closed. + +.. js:function:: AppletHTTP.send(applet, msg) + + Send the message *msg* on the http request body. + + :param class_AppletHTTP applet: An :ref:`applethttp_class` + :param string msg: the message to send. + +.. js:function:: AppletHTTP.get_priv(applet) + + Return Lua data stored in the current transaction. If no data are stored, + it returns a nil value. + + :param class_AppletHTTP applet: An :ref:`applethttp_class` + :returns: the opaque data previously stored, or nil if nothing is + available. + :see: :js:func:`AppletHTTP.set_priv` + +.. js:function:: AppletHTTP.set_priv(applet, data) + + Store any data in the current HAProxy transaction. This action replaces the + old stored data. + + :param class_AppletHTTP applet: An :ref:`applethttp_class` + :param opaque data: The data which is stored in the transaction. + :see: :js:func:`AppletHTTP.get_priv` + +.. js:function:: AppletHTTP.set_var(applet, var, value[, ifexist]) + + Converts a Lua type in a HAProxy type and store it in a variable <var>. + + :param class_AppletHTTP applet: An :ref:`applethttp_class` + :param string var: The variable name according with the HAProxy variable + syntax. + :param type value: The value associated to the variable. The type ca be string + or integer. + :param boolean ifexist: If this parameter is set to true the variable will + only be set if it was defined elsewhere (i.e. used within the configuration). + For global variables (using the "proc" scope), they will only be updated and + never created. It is highly recommended to always set this to true. + + :see: :js:func:`AppletHTTP.unset_var` + :see: :js:func:`AppletHTTP.get_var` + +.. js:function:: AppletHTTP.unset_var(applet, var) + + Unset the variable <var>. + + :param class_AppletHTTP applet: An :ref:`applethttp_class` + :param string var: The variable name according with the HAProxy variable + syntax. + :see: :js:func:`AppletHTTP.set_var` + :see: :js:func:`AppletHTTP.get_var` + +.. js:function:: AppletHTTP.get_var(applet, var) + + Returns data stored in the variable <var> converter in Lua type. + + :param class_AppletHTTP applet: An :ref:`applethttp_class` + :param string var: The variable name according with the HAProxy variable + syntax. + :see: :js:func:`AppletHTTP.set_var` + :see: :js:func:`AppletHTTP.unset_var` + +.. _applettcp_class: + +AppletTCP class +=============== + +.. js:class:: AppletTCP + + This class is used with applets that requires the 'tcp' mode. The tcp applet + can be registered with the *core.register_service()* function. They are used + for processing a tcp stream like a server in back of HAProxy. + +.. js:attribute:: AppletTCP.c + + :returns: A :ref:`converters_class` + + This attribute contains a Converters class object. + +.. js:attribute:: AppletTCP.sc + + :returns: A :ref:`converters_class` + + This attribute contains a Converters class object. The + functions of this object always return a string. + +.. js:attribute:: AppletTCP.f + + :returns: A :ref:`fetches_class` + + This attribute contains a Fetches class object. + +.. js:attribute:: AppletTCP.sf + + :returns: A :ref:`fetches_class` + + This attribute contains a Fetches class object. + +.. js:function:: AppletTCP.getline(applet) + + This function returns a string containing one line from the stream. If the + data returned doesn't contains a final '\\n' its assumed than its the last + available data before the end of stream. + + :param class_AppletTCP applet: An :ref:`applettcp_class` + :returns: a string. The string can be empty if we reach the end of the stream. + +.. js:function:: AppletTCP.receive(applet, [size]) + + Reads data from the TCP stream, according to the specified read *size*. If the + *size* is missing, the function tries to read all the content of the stream + until the end. + + :param class_AppletTCP applet: An :ref:`applettcp_class` + :param integer size: the required read size. + :returns: always return a string, the string can be empty if the connection is + closed. + +.. js:function:: AppletTCP.send(appletmsg) + + Send the message on the stream. + + :param class_AppletTCP applet: An :ref:`applettcp_class` + :param string msg: the message to send. + +.. js:function:: AppletTCP.get_priv(applet) + + Return Lua data stored in the current transaction. If no data are stored, + it returns a nil value. + + :param class_AppletTCP applet: An :ref:`applettcp_class` + :returns: the opaque data previously stored, or nil if nothing is + available. + :see: :js:func:`AppletTCP.set_priv` + +.. js:function:: AppletTCP.set_priv(applet, data) + + Store any data in the current HAProxy transaction. This action replaces the + old stored data. + + :param class_AppletTCP applet: An :ref:`applettcp_class` + :param opaque data: The data which is stored in the transaction. + :see: :js:func:`AppletTCP.get_priv` + +.. js:function:: AppletTCP.set_var(applet, var, value[, ifexist]) + + Converts a Lua type in a HAProxy type and stores it in a variable <var>. + + :param class_AppletTCP applet: An :ref:`applettcp_class` + :param string var: The variable name according with the HAProxy variable + syntax. + :param type value: The value associated to the variable. The type can be + string or integer. + :param boolean ifexist: If this parameter is set to true the variable will + only be set if it was defined elsewhere (i.e. used within the configuration). + For global variables (using the "proc" scope), they will only be updated and + never created. It is highly recommended to always set this to true. + + :see: :js:func:`AppletTCP.unset_var` + :see: :js:func:`AppletTCP.get_var` + +.. js:function:: AppletTCP.unset_var(applet, var) + + Unsets the variable <var>. + + :param class_AppletTCP applet: An :ref:`applettcp_class` + :param string var: The variable name according with the HAProxy variable + syntax. + :see: :js:func:`AppletTCP.unset_var` + :see: :js:func:`AppletTCP.set_var` + +.. js:function:: AppletTCP.get_var(applet, var) + + Returns data stored in the variable <var> converter in Lua type. + + :param class_AppletTCP applet: An :ref:`applettcp_class` + :param string var: The variable name according with the HAProxy variable + syntax. + :see: :js:func:`AppletTCP.unset_var` + :see: :js:func:`AppletTCP.set_var` + +.. _sticktable_class: + +StickTable class +================ + +.. js:class:: StickTable + + **context**: task, action, sample-fetch + + This class can be used to access the HAProxy stick tables from Lua. + +.. js:function:: StickTable.info() + + Returns stick table attributes as a Lua table. See HAProxy documentation for + "stick-table" for canonical info, or check out example below. + + :returns: Lua table + + Assume our table has IPv4 key and gpc0 and conn_rate "columns": + +.. code-block:: lua + + { + expire=<int>, # Value in ms + size=<int>, # Maximum table size + used=<int>, # Actual number of entries in table + data={ # Data columns, with types as key, and periods as values + (-1 if type is not rate counter) + conn_rate=<int>, + gpc0=-1 + }, + length=<int>, # max string length for string table keys, key length + # otherwise + nopurge=<boolean>, # purge oldest entries when table is full + type="ip" # can be "ip", "ipv6", "integer", "string", "binary" + } + +.. js:function:: StickTable.lookup(key) + + Returns stick table entry for given <key> + + :param string key: Stick table key (IP addresses and strings are supported) + :returns: Lua table + +.. js:function:: StickTable.dump([filter]) + + Returns all entries in stick table. An optional filter can be used + to extract entries with specific data values. Filter is a table with valid + comparison operators as keys followed by data type name and value pairs. + Check out the HAProxy docs for "show table" for more details. For the + reference, the supported operators are: + + "eq", "ne", "le", "lt", "ge", "gt" + + For large tables, execution of this function can take a long time (for + HAProxy standards). That's also true when filter is used, so take care and + measure the impact. + + :param table filter: Stick table filter + :returns: Stick table entries (table) + + See below for example filter, which contains 4 entries (or comparisons). + (Maximum number of filter entries is 4, defined in the source code) + +.. code-block:: lua + + local filter = { + {"gpc0", "gt", 30}, {"gpc1", "gt", 20}}, {"conn_rate", "le", 10} + } + +.. _action_class: + +Action class +============= + +.. js:class:: Act + + **context**: action + + This class contains all return codes an action may return. It is the lua + equivalent to HAProxy "ACT_RET_*" code. + +.. code-block:: lua + + core.register_action("deny", { "http-req" }, function (txn) + return act.DENY + end) +.. +.. js:attribute:: act.CONTINUE + + This attribute is an integer (0). It instructs HAProxy to continue the + current ruleset processing on the message. It is the default return code + for a lua action. + + :returns: integer + +.. js:attribute:: act.STOP + + This attribute is an integer (1). It instructs HAProxy to stop the current + ruleset processing on the message. + +.. js:attribute:: act.YIELD + + This attribute is an integer (2). It instructs HAProxy to temporarily pause + the message processing. It will be resumed later on the same rule. The + corresponding lua script is re-executed for the start. + +.. js:attribute:: act.ERROR + + This attribute is an integer (3). It triggers an internal errors The message + processing is stopped and the transaction is terminated. For HTTP streams, an + HTTP 500 error is returned to the client. + + :returns: integer + +.. js:attribute:: act.DONE + + This attribute is an integer (4). It instructs HAProxy to stop the message + processing. + + :returns: integer + +.. js:attribute:: act.DENY + + This attribute is an integer (5). It denies the current message. The message + processing is stopped and the transaction is terminated. For HTTP streams, an + HTTP 403 error is returned to the client if the deny is returned during the + request analysis. During the response analysis, a HTTP 502 error is returned + and the server response is discarded. + + :returns: integer + +.. js:attribute:: act.ABORT + + This attribute is an integer (6). It aborts the current message. The message + processing is stopped and the transaction is terminated. For HTTP streams, + HAProxy assumes a response was already sent to the client. From the Lua + actions point of view, when this code is used, the transaction is terminated + with no reply. + + :returns: integer + +.. js:attribute:: act.INVALID + + This attribute is an integer (7). It triggers an internal errors. The message + processing is stopped and the transaction is terminated. For HTTP streams, an + HTTP 400 error is returned to the client if the error is returned during the + request analysis. During the response analysis, a HTTP 502 error is returned + and the server response is discarded. + + :returns: integer + +.. js:function:: act:wake_time(milliseconds) + + **context**: action + + Set the script pause timeout to the specified time, defined in + milliseconds. + + :param integer milliseconds: the required milliseconds. + + This function may be used when a lua action returns `act.YIELD`, to force its + wake-up at most after the specified number of milliseconds. + +.. _filter_class: + +Filter class +============= + +.. js:class:: filter + + **context**: filter + + This class contains return codes some filter callback functions may return. It + also contains configuration flags and some helper functions. To understand how + the filter API works, see `doc/internal/filters.txt` documentation. + +.. js:attribute:: filter.CONTINUE + + This attribute is an integer (1). It may be returned by some filter callback + functions to instruct this filtering step is finished for this filter. + +.. js:attribute:: filter.WAIT + + This attribute is an integer (0). It may be returned by some filter callback + functions to instruct the filtering must be paused, waiting for more data or + for an external event depending on this filter. + +.. js:attribute:: filter.ERROR + + This attribute is an integer (-1). It may be returned by some filter callback + functions to trigger an error. + +.. js:attribute:: filter.FLT_CFG_FL_HTX + + This attribute is a flag corresponding to the filter flag FLT_CFG_FL_HTX. When + it is set for a filter, it means the filter is able to filter HTTP streams. + +.. js:function:: filter.register_data_filter(chn) + + **context**: filter + + Enable the data filtering on the channel **chn** for the current filter. It + may be called at any time from any callback functions proceeding the data + analysis. + + :param class_Channel chn: A :ref:`channel_class`. + +.. js:function:: filter.unregister_data_filter(chn) + + **context**: filter + + Disable the data filtering on the channel **chn** for the current filter. It + may be called at any time from any callback functions. + + :param class_Channel chn: A :ref:`channel_class`. + +.. js:function:: filter.wake_time(milliseconds) + + **context**: filter + + Set the script pause timeout to the specified time, defined in + milliseconds. + + :param integer milliseconds: the required milliseconds. + + This function may be used from any lua filter callback function to force its + wake-up at most after the specified number of milliseconds. Especially, when + `filter.CONTINUE` is returned. + + +A filters is declared using :js:func:`core.register_filter()` function. The +provided class will be used to instantiate filters. It may define following +attributes: + +* id: The filter identifier. It is a string that identifies the filter and is + optional. + +* flags: The filter flags. Only :js:attr:`filter.FLT_CFG_FL_HTX` may be set + for now. + +Such filter class must also define all required callback functions in the +following list. Note that :js:func:`Filter.new()` must be defined otherwise the +filter is ignored. Others are optional. + +* .. js:function:: FILTER.new() + + Called to instantiate a new filter. This function must be defined. + + :returns: a Lua object that will be used as filter instance for the current + stream. + +* .. js:function:: FILTER.start_analyze(flt, txn, chn) + + Called when the analysis starts on the channel **chn**. + +* .. js:function:: FILTER.end_analyze(flt, txn, chn) + + Called when the analysis ends on the channel **chn**. + +* .. js:function:: FILTER.http_headers(flt, txn, http_msg) + + Called just before the HTTP payload analysis and after any processing on the + HTTP message **http_msg**. This callback functions is only called for HTTP + streams. + +* .. js:function:: FILTER.http_payload(flt, txn, http_msg) + + Called during the HTTP payload analysis on the HTTP message **http_msg**. This + callback functions is only called for HTTP streams. + +* .. js:function:: FILTER.http_end(flt, txn, http_msg) + + Called after the HTTP payload analysis on the HTTP message **http_msg**. This + callback functions is only called for HTTP streams. + +* .. js:function:: FILTER.tcp_payload(flt, txn, chn) + + Called during the TCP payload analysis on the channel **chn**. + +Here is a full example: + +.. code-block:: lua + + Trace = {} + Trace.id = "Lua trace filter" + Trace.flags = filter.FLT_CFG_FL_HTX; + Trace.__index = Trace + + function Trace:new() + local trace = {} + setmetatable(trace, Trace) + trace.req_len = 0 + trace.res_len = 0 + return trace + end + + function Trace:start_analyze(txn, chn) + if chn:is_resp() then + print("Start response analysis") + else + print("Start request analysis") + end + filter.register_data_filter(self, chn) + end + + function Trace:end_analyze(txn, chn) + if chn:is_resp() then + print("End response analysis: "..self.res_len.." bytes filtered") + else + print("End request analysis: "..self.req_len.." bytes filtered") + end + end + + function Trace:http_headers(txn, http_msg) + stline = http_msg:get_stline() + if http_msg.channel:is_resp() then + print("response:") + print(stline.version.." "..stline.code.." "..stline.reason) + else + print("request:") + print(stline.method.." "..stline.uri.." "..stline.version) + end + + for n, hdrs in pairs(http_msg:get_headers()) do + for i,v in pairs(hdrs) do + print(n..": "..v) + end + end + return filter.CONTINUE + end + + function Trace:http_payload(txn, http_msg) + body = http_msg:body(-20000) + if http_msg.channel:is_resp() then + self.res_len = self.res_len + body:len() + else + self.req_len = self.req_len + body:len() + end + end + + core.register_filter("trace", Trace, function(trace, args) + return trace + end) + +.. + +.. _httpmessage_class: + +HTTPMessage class +=================== + +.. js:class:: HTTPMessage + + **context**: filter + + This class contains all functions to manipulate a HTTP message. For now, this + class is only available from a filter context. + +.. js:function:: HTTPMessage.add_header(http_msg, name, value) + + Appends a HTTP header field in the HTTP message **http_msg** whose name is + specified in **name** and whose value is defined in **value**. + + :param class_httpmessage http_msg: The manipulated HTTP message. + :param string name: The header name. + :param string value: The header value. + +.. js:function:: HTTPMessage.append(http_msg, string) + + This function copies the string **string** at the end of incoming data of the + HTTP message **http_msg**. The function returns the copied length on success + or -1 if data cannot be copied. + + Same that :js:func:`HTTPMessage.insert(http_msg, string, http_msg:input())`. + + :param class_httpmessage http_msg: The manipulated HTTP message. + :param string string: The data to copy at the end of incoming data. + :returns: an integer containing the amount of bytes copied or -1. + +.. js:function:: HTTPMessage.body(http_msgl[, offset[, length]]) + + This function returns **length** bytes of incoming data from the HTTP message + **http_msg**, starting at the offset **offset**. The data are not removed from + the buffer. + + By default, if no length is provided, all incoming data found, starting at the + given offset, are returned. If **length** is set to -1, the function tries to + retrieve a maximum of data. Because it is called in the filter context, it + never yield. Not providing an offset is the same as setting it to 0. A + positive offset is relative to the beginning of incoming data of the + http_message buffer while negative offset is relative to their end. + + If there is no incoming data and the HTTP message can't receive more data, + a 'nil' value is returned. + + :param class_httpmessage http_msg: The manipulated HTTP message. + :param integer offset: *optional* The offset in incoming data to start to get + data. 0 by default. May be negative to be relative to the end of incoming + data. + :param integer length: *optional* The expected length of data to retrieve. + All incoming data by default. May be set to -1 to get a maximum of data. + :returns: a string containing the data found or nil. + +.. js:function:: HTTPMessage.eom(http_msg) + + This function returns true if the end of message is reached for the HTTP + message **http_msg**. + + :param class_httpmessage http_msg: The manipulated HTTP message. + :returns: an integer containing the amount of available bytes. + +.. js:function:: HTTPMessage.del_header(http_msg, name) + + Removes all HTTP header fields in the HTTP message **http_msg** whose name is + specified in **name**. + + :param class_httpmessage http_msg: The manipulated http message. + :param string name: The header name. + +.. js:function:: HTTPMessage.get_headers(http_msg) + + Returns a table containing all the headers of the HTTP message **http_msg**. + + :param class_httpmessage http_msg: The manipulated http message. + :returns: table of headers. + + This is the form of the returned table: + +.. code-block:: lua + + http_msg:get_headers()['<header-name>'][<header-index>] = "<header-value>" + + local hdr = http_msg:get_headers() + hdr["host"][0] = "www.test.com" + hdr["accept"][0] = "audio/basic q=1" + hdr["accept"][1] = "audio/*, q=0.2" + hdr["accept"][2] = "*.*, q=0.1" +.. + +.. js:function:: HTTPMessage.get_stline(http_msg) + + Returns a table containing the start-line of the HTTP message **http_msg**. + + :param class_httpmessage http_msg: The manipulated http message. + :returns: the start-line. + + This is the form of the returned table: + +.. code-block:: lua + + -- for the request : + {"method" = string, "uri" = string, "version" = string} + + -- for the response: + {"version" = string, "code" = string, "reason" = string} +.. + +.. js:function:: HTTPMessage.forward(http_msg, length) + + This function forwards **length** bytes of data from the HTTP message + **http_msg**. Because it is called in the filter context, it never yields. Only + available incoming data may be forwarded, event if the requested length + exceeds the available amount of incoming data. It returns the amount of data + forwarded. + + :param class_httpmessage http_msg: The manipulated HTTP message. + :param integer int: The amount of data to forward. + +.. js:function:: HTTPMessage.input(http_msg) + + This function returns the length of incoming data in the HTTP message + **http_msg** from the filter point of view. + + :param class_httpmessage http_msg: The manipulated HTTP message. + :returns: an integer containing the amount of available bytes. + +.. js:function:: HTTPMessage.insert(http_msg, string[, offset]) + + This function copies the string **string** at the offset **offset** in + incoming data of the HTTP message **http_msg**. The function returns the + copied length on success or -1 if data cannot be copied. + + By default, if no offset is provided, the string is copied in front of + incoming data. A positive offset is relative to the beginning of incoming data + of the HTTP message while negative offset is relative to their end. + + :param class_httpmessage http_msg: The manipulated HTTP message. + :param string string: The data to copy into incoming data. + :param integer offset: *optional* The offset in incoming data where to copy + data. 0 by default. May be negative to be relative to the end of incoming + data. + :returns: an integer containing the amount of bytes copied or -1. + +.. js:function:: HTTPMessage.is_full(http_msg) + + This function returns true if the HTTP message **http_msg** is full. + + :param class_httpmessage http_msg: The manipulated HTTP message. + :returns: a boolean + +.. js:function:: HTTPMessage.is_resp(http_msg) + + This function returns true if the HTTP message **http_msg** is the response + one. + + :param class_httpmessage http_msg: The manipulated HTTP message. + :returns: a boolean + +.. js:function:: HTTPMessage.may_recv(http_msg) + + This function returns true if the HTTP message **http_msg** may still receive + data. + + :param class_httpmessage http_msg: The manipulated HTTP message. + :returns: a boolean + +.. js:function:: HTTPMessage.output(http_msg) + + This function returns the length of outgoing data of the HTTP message + **http_msg**. + + :param class_httpmessage http_msg: The manipulated HTTP message. + :returns: an integer containing the amount of available bytes. + +.. js:function:: HTTPMessage.prepend(http_msg, string) + + This function copies the string **string** in front of incoming data of the + HTTP message **http_msg**. The function returns the copied length on success + or -1 if data cannot be copied. + + Same that :js:func:`HTTPMessage.insert(http_msg, string, 0)`. + + :param class_httpmessage http_msg: The manipulated HTTP message. + :param string string: The data to copy in front of incoming data. + :returns: an integer containing the amount of bytes copied or -1. + +.. js:function:: HTTPMessage.remove(http_msg[, offset[, length]]) + + This function removes **length** bytes of incoming data of the HTTP message + **http_msg**, starting at offset **offset**. This function returns number of + bytes removed on success. + + By default, if no length is provided, all incoming data, starting at the given + offset, are removed. Not providing an offset is the same that setting it + to 0. A positive offset is relative to the beginning of incoming data of the + HTTP message while negative offset is relative to the end. + + :param class_httpmessage http_msg: The manipulated HTTP message. + :param integer offset: *optional* The offset in incoming data where to start + to remove data. 0 by default. May be negative to be relative to the end of + incoming data. + :param integer length: *optional* The length of data to remove. All incoming + data by default. + :returns: an integer containing the amount of bytes removed. + +.. js:function:: HTTPMessage.rep_header(http_msg, name, regex, replace) + + Matches the regular expression in all occurrences of header field **name** + according to regex **regex**, and replaces them with the string **replace**. + The replacement value can contain back references like \1, \2, ... This + function acts on whole header lines, regardless of the number of values they + may contain. + + :param class_httpmessage http_msg: The manipulated HTTP message. + :param string name: The header name. + :param string regex: The match regular expression. + :param string replace: The replacement value. + +.. js:function:: HTTPMessage.rep_value(http_msg, name, regex, replace) + + Matches the regular expression on every comma-delimited value of header field + **name** according to regex **regex**, and replaces them with the string + **replace**. The replacement value can contain back references like \1, \2, + ... + + :param class_httpmessage http_msg: The manipulated HTTP message. + :param string name: The header name. + :param string regex: The match regular expression. + :param string replace: The replacement value. + +.. js:function:: HTTPMessage.send(http_msg, string) + + This function requires immediate send of the string **string**. It means the + string is copied at the beginning of incoming data of the HTTP message + **http_msg** and immediately forwarded. Because it is called in the filter + context, it never yields. + + :param class_httpmessage http_msg: The manipulated HTTP message. + :param string string: The data to send. + :returns: an integer containing the amount of bytes copied or -1. + +.. js:function:: HTTPMessage.set(http_msg, string[, offset[, length]]) + + This function replaces **length** bytes of incoming data of the HTTP message + **http_msg**, starting at offset **offset**, by the string **string**. The + function returns the copied length on success or -1 if data cannot be copied. + + By default, if no length is provided, all incoming data, starting at the given + offset, are replaced. Not providing an offset is the same as setting it + to 0. A positive offset is relative to the beginning of incoming data of the + HTTP message while negative offset is relative to the end. + + :param class_httpmessage http_msg: The manipulated HTTP message. + :param string string: The data to copy into incoming data. + :param integer offset: *optional* The offset in incoming data where to start + the data replacement. 0 by default. May be negative to be relative to the + end of incoming data. + :param integer length: *optional* The length of data to replace. All incoming + data by default. + :returns: an integer containing the amount of bytes copied or -1. + +.. js:function:: HTTPMessage.set_eom(http_msg) + + This function set the end of message for the HTTP message **http_msg**. + + :param class_httpmessage http_msg: The manipulated HTTP message. + +.. js:function:: HTTPMessage.set_header(http_msg, name, value) + + This variable replace all occurrence of all header matching the name **name**, + by only one containing the value **value**. + + :param class_httpmessage http_msg: The manipulated HTTP message. + :param string name: The header name. + :param string value: The header value. + + This function does the same work as the following code: + +.. code-block:: lua + + http_msg:del_header("header") + http_msg:add_header("header", "value") +.. + +.. js:function:: HTTPMessage.set_method(http_msg, method) + + Rewrites the request method with the string **method**. The HTTP message + **http_msg** must be the request. + + :param class_httpmessage http_msg: The manipulated HTTP message. + :param string method: The new method. + +.. js:function:: HTTPMessage.set_path(http_msg, path) + + Rewrites the request path with the string **path**. The HTTP message + **http_msg** must be the request. + + :param class_httpmessage http_msg: The manipulated HTTP message. + :param string method: The new method. + +.. js:function:: HTTPMessage.set_query(http_msg, query) + + Rewrites the request's query string which appears after the first question + mark ("?") with the string **query**. The HTTP message **http_msg** must be + the request. + + :param class_httpmessage http_msg: The manipulated HTTP message. + :param string query: The new query. + +.. js:function:: HTTPMessage.set_status(http_msg, status[, reason]) + + Rewrites the response status code with the integer **code** and optional the + reason **reason**. If no custom reason is provided, it will be generated from + the status. The HTTP message **http_msg** must be the response. + + :param class_httpmessage http_msg: The manipulated HTTP message. + :param integer status: The new response status code. + :param string reason: The new response reason (optional). + +.. js:function:: HTTPMessage.set_uri(http_msg, uri) + + Rewrites the request URI with the string **uri**. The HTTP message + **http_msg** must be the request. + + :param class_httpmessage http_msg: The manipulated HTTP message. + :param string uri: The new uri. + +.. js:function:: HTTPMessage.unset_eom(http_msg) + + This function remove the end of message for the HTTP message **http_msg**. + + :param class_httpmessage http_msg: The manipulated HTTP message. + +.. _CertCache_class: + +CertCache class +================ + +.. js:class:: CertCache + + This class allows to update an SSL certificate file in the memory of the + current HAProxy process. It will do the same as "set ssl cert" + "commit ssl + cert" over the HAProxy CLI. + +.. js:function:: CertCache.set(certificate) + + This function updates a certificate in memory. + + :param table certificate: A table containing the fields to update. + :param string certificate.filename: The mandatory filename of the certificate + to update, it must already exist in memory. + :param string certificate.crt: A certificate in the PEM format. It can also + contain a private key. + :param string certificate.key: A private key in the PEM format. + :param string certificate.ocsp: An OCSP response in base64. (cf management.txt) + :param string certificate.issuer: The certificate of the OCSP issuer. + :param string certificate.sctl: An SCTL file. + +.. code-block:: lua + + CertCache.set{filename="certs/localhost9994.pem.rsa", crt=crt} + + +External Lua libraries +====================== + +A lot of useful lua libraries can be found here: + +* Lua toolbox has been superseded by + `https://luarocks.org/ <https://luarocks.org/>`_ + + The old lua toolbox source code is still available here + `https://github.com/catwell/lua-toolbox <https://github.com/catwell/lua-toolbox>`_ (DEPRECATED) + +Redis client library: + +* `https://github.com/nrk/redis-lua <https://github.com/nrk/redis-lua>`_ + +This is an example about the usage of the Redis library within HAProxy. +Note that each call to any function of this library can throw an error if +the socket connection fails. + +.. code-block:: lua + + -- load the redis library + local redis = require("redis"); + + function do_something(txn) + + -- create and connect new tcp socket + local tcp = core.tcp(); + tcp:settimeout(1); + tcp:connect("127.0.0.1", 6379); + + -- use the redis library with this new socket + local client = redis.connect({socket=tcp}); + client:ping(); + + end + +OpenSSL: + +* `http://mkottman.github.io/luacrypto/index.html + <http://mkottman.github.io/luacrypto/index.html>`_ + +* `https://github.com/brunoos/luasec/wiki + <https://github.com/brunoos/luasec/wiki>`_ |