Use Metal behaviour

.travis.yml

@@ -17,6 +17,7 @@ language: erlang
 notifications:
   email: false
 otp_release:
+  - 20.1
   - 19.1
   - 18.3
 script: "make travis"

doc/statsderl_server.md

@@ -4,24 +4,35 @@
 * [Function Index](#index)
 * [Function Details](#functions)
 
+__Behaviours:__ [`metal`](metal.md).
+
 <a name="index"></a>
 
 ## Function Index ##
 
 
-<table width="100%" border="1" cellspacing="0" cellpadding="2" summary="function index"><tr><td valign="top"><a href="#init-2">init/2</a></td><td></td></tr><tr><td valign="top"><a href="#start_link-1">start_link/1</a></td><td></td></tr></table>
+<table width="100%" border="1" cellspacing="0" cellpadding="2" summary="function index"><tr><td valign="top"><a href="#handle_msg-2">handle_msg/2</a></td><td></td></tr><tr><td valign="top"><a href="#init-3">init/3</a></td><td></td></tr><tr><td valign="top"><a href="#start_link-1">start_link/1</a></td><td></td></tr><tr><td valign="top"><a href="#terminate-2">terminate/2</a></td><td></td></tr></table>
 
 
 <a name="functions"></a>
 
 ## Function Details ##
 
-<a name="init-2"></a>
+<a name="handle_msg-2"></a>
+
+### handle_msg/2 ###
+
+<pre><code>
+handle_msg(X1::term(), State::term()) -&gt; {ok, term()}
+</code></pre>
+<br />
+
+<a name="init-3"></a>
 
-### init/2 ###
+### init/3 ###
 
 <pre><code>
-init(Parent::pid(), Name::atom()) -&gt; no_return()
+init(Name::atom(), Parent::pid(), Opts::term()) -&gt; {ok, term()} | {stop, atom()}
 </code></pre>
 <br />
 
@@ -34,3 +45,12 @@ start_link(Name::atom()) -&gt; {ok, pid()}
 </code></pre>
 <br />
 
+<a name="terminate-2"></a>
+
+### terminate/2 ###
+
+<pre><code>
+terminate(Reason::term(), State::term()) -&gt; ok
+</code></pre>
+<br />
+

rebar.config

@@ -12,6 +12,7 @@
 {deps, [
   {foil, "0.1.0"},
   {granderl, "0.1.5"},
+  {metal, "0.1.1"},
   {parse_trans, "3.0.0"}
 ]}.
 

rebar.lock

@@ -1,7 +1,7 @@
 {"1.1.0",
 [{<<"foil">>,{pkg,<<"foil">>,<<"0.1.0">>},0},
  {<<"granderl">>,{pkg,<<"granderl">>,<<"0.1.5">>},0},
- {<<"metal">>,{pkg,<<"metal">>,<<"0.1.1">>},1},
+ {<<"metal">>,{pkg,<<"metal">>,<<"0.1.1">>},0},
  {<<"parse_trans">>,{pkg,<<"parse_trans">>,<<"3.0.0">>},0}]}.
 [
 {pkg_hash,[

src/statsderl.app.src

@@ -1,5 +1,5 @@
 {application, statsderl, [
-  {applications, [kernel, stdlib, granderl, foil]},
+  {applications, [kernel, stdlib, granderl, foil, metal]},
   {description, "High Performance Erlang StatsD Client"},
   {env, []},
   {licenses, ["MIT"]},

src/statsderl_server.erl

@@ -5,20 +5,33 @@
 -compile({inline_size, 512}).
 
 -export([
-    init/2,
     start_link/1
 ]).
 
+-behaviour(metal).
+-export([
+    init/3,
+    handle_msg/2,
+    terminate/2
+]).
+
 -record(state, {
     header :: iodata(),
     socket :: inet:socket()
 }).
 
 %% public
--spec init(pid(), atom()) ->
-    no_return().
+-spec start_link(atom()) ->
+    {ok, pid()}.
 
-init(Parent, Name) ->
+start_link(Name) ->
+    metal:start_link(?SERVER, Name, undefined).
+
+%% metal callbacks
+-spec init(atom(), pid(), term()) ->
+    {ok, term()} | {stop, atom()}.
+
+init(_Name, _Parent, _Opts) ->
     BaseKey = ?ENV(?ENV_BASEKEY, ?DEFAULT_BASEKEY),
     Hostname = ?ENV(?ENV_HOSTNAME, ?DEFAULT_HOSTNAME),
     Port = ?ENV(?ENV_PORT, ?DEFAULT_PORT),
@@ -27,43 +40,40 @@ init(Parent, Name) ->
         {ok, Header} ->
             case gen_udp:open(0, [{active, false}]) of
                 {ok, Socket} ->
-                    register(Name, self()),
-                    proc_lib:init_ack(Parent, {ok, self()}),
-
-                    loop(#state {
+                    {ok, #state {
                         socket = Socket,
                         header = Header
-                    });
+                    }};
                 {error, Reason} ->
-                    exit(Reason)
+                    {stop, Reason}
             end;
         {error, Reason} ->
-            exit(Reason)
+            {stop, Reason}
     end.
 
--spec start_link(atom()) ->
-    {ok, pid()}.
+-spec handle_msg(term(), term()) ->
+    {ok, term()}.
 
-start_link(Name) ->
-    proc_lib:start_link(?MODULE, init, [self(), Name]).
-
-%% private
-loop(#state {
+handle_msg({cast, Packet}, #state {
         header = Header,
         socket = Socket
     } = State) ->
 
-    receive
-        {cast, Packet} ->
-            erlang:port_command(Socket, [Header, Packet]),
-            loop(State);
-        {inet_reply, _Socket, ok} ->
-            loop(State);
-        {inet_reply, _Socket, {error, Reason}} ->
-            statsderl_utils:error_msg("inet_reply error: ~p~n", [Reason]),
-            loop(State)
-    end.
+    erlang:port_command(Socket, [Header, Packet]),
+    {ok, State};
+handle_msg({inet_reply, _Socket, ok}, State) ->
+    {ok, State};
+handle_msg({inet_reply, _Socket, {error, Reason}}, State) ->
+    statsderl_utils:error_msg("inet_reply error: ~p~n", [Reason]),
+    {ok, State}.
+
+-spec terminate(term(), term()) ->
+    ok.
 
+terminate(_Reason, _State) ->
+    ok.
+
+%% private
 udp_header(Hostname, Port, BaseKey) ->
     case statsderl_utils:getaddrs(Hostname) of
         {ok, {A, B, C, D}} ->