Merge pull request statsd#31 from mrtazz/erlang-example

Erlang example

statsd.erl

@@ -0,0 +1,159 @@
+%%
+%% Example erlang client implementation for the Etsy statsd
+%%
+%% Copyright (c) 2011 Daniel Schauenberg
+%%
+%% Permission is hereby granted, free of charge, to any person
+%% obtaining a copy of this software and associated documentation
+%% files (the "Software"), to deal in the Software without
+%% restriction, including without limitation the rights to use,
+%% copy, modify, merge, publish, distribute, sublicense, and/or sell
+%% copies of the Software, and to permit persons to whom the
+%% Software is furnished to do so, subject to the following
+%% conditions:
+%%
+%% The above copyright notice and this permission notice shall be
+%% included in all copies or substantial portions of the Software.
+%%
+%% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+%% EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+%% OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+%% NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+%% HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+%% WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+%% FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+%% OTHER DEALINGS IN THE SOFTWARE.
+%%
+%% Implements the following functions:
+%%   increment(Stat, Value, Sample) -> Increment the counter for Stat.
+%%   decrement(Stat, Value, Sample) -> Decrement the counter for Stat.
+%%   timing(Stat, Value, Sample) -> Record timing for Stat.
+%%
+%% Run tests with:
+%%   Run statsd with the parameters set in the -defines()
+%%   % erlc -pa /path/to/eunit/ebin -DTEST -o.statsd.erl
+%%   % erl -noshell -pa. -eval "eunit:test(statsd, [verbose])" -s init stop
+%%
+%%
+-module(statsd).
+% Meta information
+-author("Daniel Schauenberg <d@unwiredcouch.com>").
+% defines
+-define(HOST, "localhost").
+-define(PORT, 8125).
+% exports
+-export([increment/1,increment/2,increment/3,
+         decrement/1, decrement/2, timing/2,
+         timing/3]).
+
+%
+% API functions
+%
+
+% functions for incrementing counters
+increment(Stat) -> increment(Stat, 1, 1.0).
+increment(Stat, Delta) when is_integer(Delta) ->
+  increment(Stat, Delta, 1.0);
+increment(Stat, Samplerate) when is_float(Samplerate) ->
+  increment(Stat, 1, Samplerate).
+increment(Stat, Delta, Samplerate) when is_integer(Delta), is_float(Samplerate) ->
+  send({counter, Stat, Delta, Samplerate}).
+
+% functions for decrementing counters
+decrement(Stat) -> decrement(Stat, 1, 1.0).
+decrement(Stat, Delta) when is_integer(Delta) ->
+  decrement(Stat, Delta, 1.0);
+decrement(Stat, Samplerate) when is_float(Samplerate) ->
+  decrement(Stat, 1, Samplerate).
+decrement(Stat, Delta, Samplerate) when is_integer(Delta), is_float(Samplerate) ->
+  send({counter, Stat, -abs(Delta), Samplerate}).
+
+% functions for timing values
+timing(Stat, Time) when is_float(Time); is_integer(Time) ->
+  timing(Stat, Time, 1.0).
+timing(Stat, Time, Samplerate) when is_float (Time); is_integer(Time),
+                                    is_float(Samplerate) ->
+  send({timer, Stat, Time, Samplerate}).
+
+%
+% update functions
+%
+
+% recursive functions for multiple stats
+send({counter, [H|Stats], Delta, Samplerate}) ->
+  send({counter, H, Delta, Samplerate}),
+  send({counter, Stats, Delta, Samplerate});
+send({counter, [], _, _}) -> {ok, "Success."};
+send({timer, [H|Stats], Delta, Samplerate}) ->
+  send({timer, H, Delta, Samplerate}),
+  send({timer, Stats, Delta, Samplerate});
+send({timer, [], _, _}) -> {ok, "Success."};
+
+% functions for single stats
+send({counter, Stat, Delta, Samplerate}) when Samplerate < 1.0, is_atom(Stat) ->
+  Rand = random:uniform(),
+  if
+    Rand =< Samplerate ->
+      send_udp_message(?HOST, ?PORT, io_lib:format("~p:~p|c|@~p",
+                                                   [Stat, Delta, Samplerate]));
+    true -> {ok, "Success."}
+  end;
+
+send({counter, Stat, Delta, _}) ->
+  send_udp_message(?HOST, ?PORT, io_lib:format("~p:~p|c", [Stat, Delta]));
+
+send({timer, Stat, Time, Samplerate}) when Samplerate < 1.0 ->
+  Rand = random:uniform(),
+  if
+    Rand =< Samplerate ->
+      send_udp_message(?HOST, ?PORT, io_lib:format("~p:~p|ms|@~p",
+                                                   [Stat, Time, Samplerate]));
+    true -> {ok, "Success."}
+  end;
+
+send({timer, Stat, Time, _}) ->
+  send_udp_message(?HOST, ?PORT, io_lib:format("~p:~p|ms", [Stat, Time])).
+
+%
+% Raw UDP send message function
+%
+send_udp_message(Host, Port, Msg) when is_integer(Port),
+                                         is_list(Host) ->
+  {ok, Socket} = gen_udp:open(0, [binary]),
+  ok = gen_udp:send(Socket, Host, Port, Msg),
+  gen_udp:close(Socket),
+  {ok, "Success."}.
+
+%
+% unit tests
+%
+% EUnit headers
+-ifdef(TEST).
+-include_lib("eunit/include/eunit.hrl").
+% test functions go here
+increment_test_() ->
+  [?_assert(increment(stat1) =:= {ok, "Success."}),
+   ?_assert(increment(stat1, 1) =:= {ok, "Success."}),
+   ?_assert(increment(stat1, 1, 0.5) =:= {ok, "Success."}),
+   ?_assert(increment([stat1, stat2]) =:= {ok, "Success."}),
+   ?_assert(increment([stat1, stat2], 1) =:= {ok, "Success."}),
+   ?_assert(increment([stat1, stat2], 1, 0.5) =:= {ok, "Success."})
+       ].
+decrement_test_() ->
+  [?_assert(decrement(stat1) =:= {ok, "Success."}),
+   ?_assert(decrement(stat1, 1) =:= {ok, "Success."}),
+   ?_assert(decrement(stat1, -1) =:= {ok, "Success."}),
+   ?_assert(decrement(stat1, 1, 0.5) =:= {ok, "Success."}),
+   ?_assert(decrement([stat1, stat2]) =:= {ok, "Success."}),
+   ?_assert(decrement([stat1, stat2], 1) =:= {ok, "Success."}),
+   ?_assert(decrement([stat1, stat2], -1) =:= {ok, "Success."}),
+   ?_assert(decrement([stat1, stat2], 1, 0.5) =:= {ok, "Success."})
+       ].
+timing_test_() ->
+  [
+   ?_assert(timing(stat1, 100) =:= {ok, "Success."}),
+   ?_assert(timing(stat1, 100, 0.5) =:= {ok, "Success."}),
+   ?_assert(timing([stat1, stat2], 100) =:= {ok, "Success."}),
+   ?_assert(timing([stat1, stat2], 100, 0.5) =:= {ok, "Success."})
+       ].
+-endif.