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-rw-r--r--examples/lua/mailers.lua426
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diff --git a/examples/lua/mailers.lua b/examples/lua/mailers.lua
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+-- haproxy mailers implementation in lua
+--
+-- Provides a pure lua alternative to tcpcheck mailers.
+--
+-- To be loaded using "lua-load" from haproxy configuration to handle
+-- email-alerts directly from lua and disable legacy tcpcheck implementation.
+
+local SYSLOG_LEVEL = {
+ ["EMERG"] = 0,
+ ["ALERT"] = 1,
+ ["CRIT"] = 2,
+ ["ERROR"] = 3,
+ ["WARN"] = 4,
+ ["NOTICE"] = 5,
+ ["INFO"] = 6,
+ ["DEBUG"] = 7
+}
+
+local mailqueue = core.queue()
+
+-- smtp : send SMTP message
+--
+-- Copyright 2018 Thierry Fournier
+--
+-- This function is compliant with HAProxy cosockets
+-- EHLO was replaced with HELO for better compatibility with
+-- basic mail server implementations
+--
+-- <server> should contain the full server address (including port) in the
+-- same format used in haproxy config file. It will be passed as it is to
+-- tcp::connect() without explicit port argument. See Socket.connect()
+-- manual for more information.
+--
+-- The function will abort after <timeout> ms
+function smtp_send_email(server, timeout, domain, from, to, data)
+ local ret
+ local reason
+ local tcp = core.tcp()
+ local smtp_wait_code = function(tcp, code)
+ local ret
+ -- Read headers until we reac a 2.. code.
+ while true do
+ -- read line
+ ret = tcp:receive("*l")
+ if ret == nil then
+ return false, "Connection unexpectedly closed"
+ end
+ -- expected code
+ if string.match(ret, code) ~= nil then
+ return true, nil
+ end
+ -- other code
+ if string.match(ret, '^%d%d%d ') ~= nil then
+ return false, ret
+ end
+ -- other informational message, wait.
+ end
+ end
+
+ if timeout ~= nil and timeout > 0 then
+ tcp:settimeout(timeout / 1000)
+ end
+
+ if tcp:connect(server) == nil then
+ return false, "Can't connect to \""..server.."\""
+ end
+
+ ret, reason = smtp_wait_code(tcp, '^220 ')
+ if ret == false then
+ tcp:close()
+ return false, reason
+ end
+
+ if tcp:send("HELO " .. domain .. "\r\n") == nil then
+ tcp:close()
+ return false, "Connection unexpectedly closed"
+ end
+
+ ret, reason = smtp_wait_code(tcp, '^250 ')
+ if ret == false then
+ tcp:close()
+ return false, reason
+ end
+
+ if tcp:send("MAIL FROM: <" .. from .. ">\r\n") == nil then
+ tcp:close()
+ return false, "Connection unexpectedly closed"
+ end
+
+ ret, reason = smtp_wait_code(tcp, '^250 ')
+ if ret == false then
+ tcp:close()
+ return false, reason
+ end
+
+ if tcp:send("RCPT TO: <" .. to .. ">\r\n") == nil then
+ tcp:close()
+ return false, "Connection unexpectedly closed"
+ end
+
+ ret, reason = smtp_wait_code(tcp, '^250 ')
+ if ret == false then
+ tcp:close()
+ return false, reason
+ end
+
+ if tcp:send("DATA\r\n") == nil then
+ tcp:close()
+ return false, "Connection unexpectedly closed"
+ end
+
+ ret, reason = smtp_wait_code(tcp, '^354 ')
+ if ret == false then
+ tcp:close()
+ return false, reason
+ end
+
+ if tcp:send(data .. "\r\n.\r\n") == nil then
+ tcp:close()
+ return false, "Connection unexpectedly closed"
+ end
+
+ ret, reason = smtp_wait_code(tcp, '^250 ')
+ if ret == false then
+ tcp:close()
+ return false, reason
+ end
+
+ if tcp:send("QUIT\r\n") == nil then
+ tcp:close()
+ return false, "Connection unexpectedly closed"
+ end
+
+ ret, reason = smtp_wait_code(tcp, '^221 ')
+ if ret == false then
+ tcp:close()
+ return false, reason
+ end
+
+ tcp:close()
+ return true, nil
+end
+
+local function send_email_alert(srv, level, message, when)
+ local mailers = srv:get_proxy():get_mailers()
+
+ if mailers == nil then
+ return -- nothing to do
+ end
+
+ if level > mailers.log_level then
+ return
+ end
+
+ -- email sending is performed asynchronously thanks to mailqueue
+ local job = {}
+
+ job.mailconf = mailers
+ job.when = when
+ job.msg = message
+
+ -- enqueue email job
+ mailqueue:push(job)
+
+end
+
+local function srv_get_check_details(check)
+ local c = core.concat()
+
+ c:add(", ")
+ c:add(string.format("reason: %s", check.reason.desc))
+ if check.reason.code ~= nil
+ then
+ c:add(string.format(", code: %d", check.reason.code))
+ end
+ if check.duration >= 0
+ then
+ c:add(string.format(", check duration: %dms", check.duration))
+ end
+
+ return c:dump()
+end
+
+local function srv_get_status_details(srv, requeued)
+ local c = core.concat()
+
+ c:add(string.format("%d active and %d backup servers left.",
+ srv:get_proxy():get_srv_act(),
+ srv:get_proxy():get_srv_bck()))
+ c:add(" ")
+ c:add(string.format("%d sessions active, %d requeued, %d remaining in queue",
+ srv:get_cur_sess(),
+ requeued,
+ srv:get_pend_conn()))
+ return c:dump()
+end
+
+local function srv_state_handler(event, data, when)
+ local server = data.reference
+ local state = data.state
+ local c = core.concat()
+ local log_level = SYSLOG_LEVEL["ALERT"]
+ local message
+
+ if server == nil then
+ -- server already removed, can't do much
+ return
+ end
+
+ if state.admin then
+ -- don't report if is related to an administrative change and not
+ -- directly due to an operational change
+ return
+ end
+
+ -- we don't send an alert if the server was previously stopping
+ if state.old_state == "STOPPING" or server:is_draining() then
+ log_level = SYSLOG_LEVEL["NOTICE"]
+ end
+
+ -- prepare the message
+ c:add(string.format("Server %s/%s is %s",
+ server:get_proxy():get_name(),
+ server:get_name(),
+ state.new_state == "RUNNING" and "UP" or "DOWN"))
+
+ if server:tracking()
+ then
+ -- server is tracking another server, it means that the operational
+ -- state change is inherited
+ c:add(string.format(" via %s/%s",
+ server:tracking():get_proxy():get_name(),
+ server:tracking():get_name()))
+ end
+
+ if state.check ~= nil
+ then
+ c:add(srv_get_check_details(state.check))
+ else
+ c:add(state.cause)
+ end
+
+ c:add(". ")
+ c:add(srv_get_status_details(server, state.requeued))
+ send_email_alert(server, log_level, c:dump(), when)
+end
+
+local function srv_admin_handler(event, data, when)
+ local server = data.reference
+ local admin = data.admin
+ local c = core.concat()
+
+ if server == nil then
+ -- server already removed, can't do much
+ return
+ end
+
+ -- only send an email when server is entering drain state and not under maint
+ if not (not admin.old_admin["DRAIN"] and
+ admin.new_admin["DRAIN"] and
+ not admin.new_admin["MAINT"]) then
+ return
+ end
+
+ -- prepare the message
+ c:add(string.format("Server %s/%s enters drain state",
+ server:get_proxy():get_name(),
+ server:get_name()))
+
+ if server:tracking() and admin.new_admin["IDRAIN"]
+ then
+ -- server is tracking another server and IDRAIN is set, it means
+ -- that the admin state change is inherited
+ c:add(string.format(" via %s/%s",
+ server:tracking():get_proxy():get_name(),
+ server:tracking():get_name()))
+ end
+
+ c:add(". ")
+ c:add(srv_get_status_details(server, admin.requeued))
+ send_email_alert(server, SYSLOG_LEVEL["NOTICE"], c:dump(), when)
+end
+
+local function srv_check_handler(event, data, when)
+ local server = data.reference
+ local check = data.check
+ local c = core.concat()
+
+ if server == nil then
+ -- server already removed, can't do much
+ return
+ end
+
+ -- we will always send an email, prepare the message
+ c:add(string.format("%s check for %sserver %s/%s ",
+ check.agent and "Agent" or "Health",
+ server:is_backup() and "backup " or "",
+ server:get_proxy():get_name(),
+ server:get_name()))
+
+ if check.result == "CONDPASS" then
+ c:add("conditionally succeeded")
+ elseif check.result == "PASSED" then
+ c:add("succeeded")
+ else
+ c:add("failed")
+ end
+
+ c:add(srv_get_check_details(check))
+
+ c:add(", status: ")
+ if check.health.cur >= check.health.rise then
+ -- good
+ c:add(string.format("%d/%d %s",
+ check.health.cur - check.health.rise + 1,
+ check.health.fall,
+ server:get_weight() and "UP" or "DRAIN"))
+ else
+ -- bad
+ c:add(string.format("%d/%d DOWN",
+ check.health.cur,
+ check.health.rise))
+ end
+
+ send_email_alert(server, SYSLOG_LEVEL["INFO"], c:dump(), when)
+end
+
+-- single function for multiple event types since all events come
+-- from the same subscription to reduce memory footprint
+local function srv_event_dispatch(event, data, mgmt, when)
+ if event == "SERVER_STATE" then srv_state_handler(event, data, when) end
+ if event == "SERVER_ADMIN" then srv_admin_handler(event, data, when) end
+ if event == "SERVER_CHECK" then srv_check_handler(event, data, when) end
+end
+
+local function mailers_track_server_events(srv)
+ local mailer_conf = srv:get_proxy():get_mailers()
+
+ -- don't track server events if the parent proxy did not enable email alerts
+ if mailer_conf == nil
+ then return
+ end
+
+ -- email alerts are enabled, track server state and admin changes
+ local subscriptions = {"SERVER_STATE", "SERVER_ADMIN"}
+
+ if mailer_conf.track_server_health
+ then
+ -- track server check events as well (this event source is expensive)
+ table.insert(subscriptions, "SERVER_CHECK")
+ end
+
+ -- perform the event subscription from the server
+ srv:event_sub(subscriptions, srv_event_dispatch)
+end
+
+local function srv_event_add(event, data)
+ -- do nothing if the server was already removed
+ if data.reference == nil
+ then return
+ end
+
+ -- server still exists, check if it can be tracked for email alerts
+ mailers_track_server_events(data.reference)
+end
+
+
+-- disable legacy email-alerts since email-alerts will be sent from lua directly
+core.disable_legacy_mailers()
+
+-- event subscriptions are purposely performed in an init function to prevent
+-- email alerts from being generated too early (when process is starting up)
+core.register_init(function()
+
+ -- do nothing if not on primary thread
+ -- this prevents emails from being sent multiple times when
+ -- lua-load-per-thread is used to load the script since the task
+ -- will be started on each haproxy thread
+ if core.thread > 1 then core.done() end
+
+ -- subscribe to SERVER_ADD to be notified when new servers are added
+ core.event_sub({"SERVER_ADD"}, srv_event_add)
+
+ -- loop through existing backends to detect existing servers
+ for backend_name, backend in pairs(core.backends) do
+ for srv_name, srv in pairs(backend.servers) do
+ mailers_track_server_events(srv)
+ end
+ end
+
+end)
+
+-- mail queue
+core.register_task(function()
+ while true
+ do
+ local job = mailqueue:pop_wait()
+
+ if job ~= nil then
+ local date = os.date("%a, %d %b %Y %T %z (%Z)", job.when)
+ local c = core.concat()
+
+ -- prepare email body
+ c:add(string.format("From: %s\r\n", job.mailconf.smtp_from))
+ c:add(string.format("To: %s\r\n", job.mailconf.smtp_to))
+ c:add(string.format("Date: %s\r\n", date))
+ c:add(string.format("Subject: [HAProxy Alert] %s\r\n", job.msg))
+ c:add("\r\n")
+ c:add(string.format("%s\r\n", job.msg))
+
+ -- send email to all mailservers
+ for name, mailsrv in pairs(job.mailconf.mailservers) do
+ -- finally, send email to server
+ local ret, reason = smtp_send_email(mailsrv,
+ job.mailconf.mailservers_timeout,
+ job.mailconf.smtp_hostname,
+ job.mailconf.smtp_from,
+ job.mailconf.smtp_to,
+ c:dump())
+ if ret == false then
+ core.Warning("Can't send email alert to ".. name .. ": " .. reason)
+ end
+ end
+ end
+ end
+end)