modules/graphite: push metrics to graphite server(s)

diff --git a/modules/graphite/README.rst b/modules/graphite/README.rst
new file mode 100644 (file)
index 0000000..da6e3b0
--- /dev/null
+++ b/modules/graphite/README.rst
@@ -0,0 +1,48 @@
+.. _mod-graphite:
+
+Graphite module
+---------------
+
+The module sends statistics over the Graphite_ protocol to either Graphite_, Metronome_, InfluxDB_ or any compatible storage. This allows powerful visualization over metrics collected by Knot DNS Resolver. 
+
+.. tip:: The Graphite server is challenging to get up and running, InfluxDB_ combined with Grafana_ are much easier, and provide richer set of options and available front-ends. Metronome_ by PowerDNS alternatively provides a mini-graphite server for much simpler setups.
+
+Example configuration
+^^^^^^^^^^^^^^^^^^^^^
+
+Only the ``host`` parameter is mandatory.
+
+.. warning:: It uses UDP so it doesn't guarantee the delivery, make sure the target server supports UDP.
+
+.. code-block:: lua
+
+       modules = {
+               graphite = {
+                       prefix = hostname(), -- optional metric prefix
+                       host = '127.0.0.1',  -- graphite server address
+                       port = 2003,         -- graphite server port
+                       interval = 5 * sec   -- publish interval
+               }
+       }
+
+The module support sending data to multiple servers at once.
+
+.. code-block:: lua
+
+       modules = {
+               graphite = {
+                       host = { '127.0.0.1', '1.2.3.4', '::1' },
+               }
+       }
+
+Dependencies
+^^^^^^^^^^^^
+
+* `luasocket <http://w3.impa.br/~diego/software/luasocket/>`_ available in LuaRocks
+
+    ``$ luarocks install socket``
+
+.. _Graphite: http://graphite.readthedocs.org/en/latest/feeding-carbon.html
+.. _InfluxDB: http://influxdb.com/
+.. _Metronome: https://github.com/ahuPowerDNS/metronome
+.. _Grafana: http://grafana.org/
\ No newline at end of file

diff --git a/modules/graphite/graphite.lua b/modules/graphite/graphite.lua
new file mode 100644 (file)
index 0000000..db75317
--- /dev/null
+++ b/modules/graphite/graphite.lua
@@ -0,0 +1,75 @@
+--- @module graphite
+local graphite = {}
+
+function graphite.init(module)
+       graphite.socket = require('socket')
+       graphite.ev = nil
+       graphite.cli = {}
+       graphite.prefix = nil
+       return 0
+end
+
+function graphite.deinit(module)
+       if graphite.ev then event.cancel(graphite.ev) end
+       return 0
+end
+
+-- @function Publish results to the Graphite server(s)
+function graphite.publish()
+       local now = os.time()
+       if not graphite.cli then error("no graphite server configured") end
+       local now_metrics = stats.list()
+       if type(now_metrics) ~= 'table' then
+               return 0 -- No metrics to watch
+       end
+       for key,val in pairs(now_metrics) do
+               for i in pairs(graphite.cli) do
+                       msg = key..' '..val..' '..now..'\n'
+                       if graphite.prefix then
+                               msg = prefix..'.'..msg
+                       end
+                       graphite.cli[i]:send(msg)
+               end
+       end
+       return 0
+end
+
+-- @function Make connection to Graphite server.
+function graphite.add_server(graphite, host, port)
+       local cli, err, status
+       if host:find(':') then
+               cli, err = graphite.socket.udp6()
+       else
+               cli, err = graphite.socket.udp()
+       end
+       if not cli then
+               error(err)
+       end
+       status, err = cli:setpeername(host, port)
+       if not status then
+               error(err)
+       end
+       table.insert(graphite.cli, cli)
+       return 0
+end
+
+function graphite.config(conf)
+       -- config defaults
+       if not conf.port then conf.port = 2003 end
+       if not conf.interval then conf.interval = 5 * sec end
+       if conf.prefix then graphite.prefix = conf.prefix end
+       -- connect to host(s)
+       if type(conf.host) == 'table' then
+               for key, val in pairs(conf.host) do
+                       graphite:add_server(val, conf.port)
+               end
+       else
+               graphite:add_server(conf.host, conf.port)
+       end
+       -- start publishing stats
+       if graphite.ev then event.cancel(graphite.ev) end
+       graphite.ev = event.recurrent(conf.interval, graphite.publish)
+       return 0
+end
+
+return graphite

diff --git a/modules/graphite/graphite.mk b/modules/graphite/graphite.mk
new file mode 100644 (file)
index 0000000..615f8be
--- /dev/null
+++ b/modules/graphite/graphite.mk
@@ -0,0 +1,2 @@
+graphite_SOURCES := graphite.lua
+$(call make_lua_module,graphite)

diff --git a/modules/modules.mk b/modules/modules.mk
index d0b08484adf9ba44e963a546054735e6b15e6e11..dfbf1d66b5706c7cb3c38304c64e1aa4660a0afa 100644 (file)
--- a/modules/modules.mk
+++ b/modules/modules.mk
@@ -5,7 +5,8 @@ modules_TARGETS := hints \
 
 # List of Lua modules
 ifeq ($(HAS_lua),yes)
-modules_TARGETS += ketcd 
+modules_TARGETS += ketcd \
+                   graphite
 endif
 
 # List of Golang modules