Adding upstream version 3.2.1.upstream/3.2.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

3 files changed, 101 insertions, 0 deletions

diff --git a/modules/etcd/README.rst b/modules/etcd/README.rst
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+.. _mod-etcd:
+
+Etcd module
+-----------
+
+The module connects to Etcd peers and watches for configuration change.
+By default, the module looks for the subtree under ``/knot-resolver`` directory,
+but you can change this `in the configuration <https://github.com/mah0x211/lua-etcd#cli-err--etcdnew-optiontable->`_.
+
+The subtree structure corresponds to the configuration variables in the declarative style.
+
+.. code-block:: bash
+
+	$ etcdctl set /knot-resolvevr/net/127.0.0.1 53
+	$ etcdctl set /knot-resolver/cache/size 10000000
+
+Configures all listening nodes to following configuration:
+
+.. code-block:: lua
+
+	net = { '127.0.0.1' }
+	cache.size = 10000000
+
+Example configuration
+^^^^^^^^^^^^^^^^^^^^^
+
+.. code-block:: lua
+
+	modules = {
+		etcd = {
+			prefix = '/knot-resolver',
+			peer = 'http://127.0.0.1:7001'
+		}
+	}
+
+.. warning:: Work in progress!
+
+Dependencies
+^^^^^^^^^^^^
+
+* `lua-etcd <https://github.com/mah0x211/lua-etcd>`_ available in LuaRocks
+
+    ``$ luarocks install etcd --from=https://mah0x211.github.io/rocks/``
+
diff --git a/modules/etcd/etcd.lua b/modules/etcd/etcd.lua
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+--- @module etcd
+local etcd = {}
+
+-- @function update subtree configuration
+local function update_subtree(tree)
+	if not tree then return end
+	for _, k in pairs(tree) do
+		if k.dir then
+			update_subtree(k.nodes)
+		else
+			local key,opt = k.key:gmatch('([^/]+)/([^/]+)$')()
+			if _G[key][opt] ~= k.value then
+				_G[key][opt] = k.value
+			end
+		end
+	end
+end
+
+-- @function reload whole configuration
+function etcd.reload()
+	local res, err = etcd.cli:readdir('/', true)
+	if err then
+		error(err)
+	end
+	update_subtree(res.body.node.nodes)
+end
+
+function etcd.init()
+	etcd.Etcd = require('etcd.luasocket')
+	etcd.defaults = { prefix = '/knot-resolver' }
+end
+
+function etcd.deinit()
+	if etcd.ev then event.cancel(etcd.ev) end
+end
+
+function etcd.config(conf)
+	local options = etcd.defaults
+	if type(conf) == 'table' then
+		for k,v in pairs(conf) do options[k] = v end
+	end
+	-- create connection
+	local cli, err = etcd.Etcd.new(options)
+	if err then
+		error(err)
+	end
+	etcd.cli = cli
+	-- schedule recurrent polling
+	-- @todo: the etcd has watch() API, but this requires
+	--        coroutines on socket operations
+	if etcd.ev then event.cancel(etcd.ev) end
+	etcd.ev = event.recurrent(5 * sec, etcd.reload)
+end
+
+return etcd
diff --git a/modules/etcd/etcd.mk b/modules/etcd/etcd.mk
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+etcd_SOURCES := etcd.lua
+$(call make_lua_module,etcd)