feat(opts): turn connection process MFA into option

Thus, making it possible to change it at runtime with the help of
`esockd:setopts/2`.

Author: keynslug

src/esockd.erl

@@ -21,18 +21,26 @@
 -export([start/0]).
 
 %% Core API
--export([ open/4
-        , open_udp/4
-        , open_dtls/4
+-export([ open/3
+        , open_udp/3
+        , open_dtls/3
         , close/2
         , close/1
+        %% Legacy API
+        , open/4
+        , open_udp/4
+        , open_dtls/4
         ]).
 
 -export([ reopen/1
         , reopen/2
         ]).
 
--export([ child_spec/4
+-export([ child_spec/3
+        , udp_child_spec/3
+        , dtls_child_spec/3
+        %% Legacy API
+        , child_spec/4
         , udp_child_spec/4
         , dtls_child_spec/4
         ]).
@@ -67,6 +75,7 @@
 -export([ merge_opts/2
         , changed_opts/2
         , parse_opt/1
+        , start_mfargs/3
         , ulimit/0
         , fixaddr/1
         , to_string/1
@@ -95,6 +104,7 @@
 -type(option() :: {acceptors, pos_integer()}
                 | {max_connections, pos_integer()}
                 | {max_conn_rate, conn_limit()}
+                | {connection_mfargs, mfargs()}
                 | {access_rules, [esockd_access:rule()]}
                 | {shutdown, brutal_kill | infinity | pos_integer()}
                 | tune_buffer | {tune_buffer, boolean()}
@@ -126,35 +136,51 @@ start() ->
 %% Open & Close
 
 %% @doc Open a TCP or SSL listener
--spec(open(atom(), listen_on(), [option()], mfargs()) -> {ok, pid()} | {error, term()}).
-open(Proto, Port, Opts, MFA) when is_atom(Proto), is_integer(Port) ->
-	esockd_sup:start_listener(Proto, Port, Opts, MFA);
-open(Proto, {Host, Port}, Opts, MFA) when is_atom(Proto), is_integer(Port) ->
+-spec open(atom(), listen_on(), options()) -> {ok, pid()} | {error, term()}.
+open(Proto, Port, Opts) when is_atom(Proto), is_integer(Port) ->
+	esockd_sup:start_child(child_spec(Proto, Port, Opts));
+open(Proto, {Host, Port}, Opts) when is_atom(Proto), is_integer(Port) ->
     {IPAddr, _Port} = fixaddr({Host, Port}),
     case proplists:get_value(ip, tcp_options(Opts)) of
         undefined -> ok;
         IPAddr    -> ok;
         Other     -> error({badmatch, Other})
     end,
-	esockd_sup:start_listener(Proto, {IPAddr, Port}, Opts, MFA).
+	esockd_sup:start_child(child_spec(Proto, {IPAddr, Port}, Opts)).
 
 %% @private
 tcp_options(Opts) ->
     proplists:get_value(tcp_options, Opts, []).
 
+%% @doc Open a TCP or SSL listener
+-spec open(atom(), listen_on(), [option()], mfargs()) -> {ok, pid()} | {error, term()}.
+open(Proto, Port, Opts, MFA) ->
+	open(Proto, Port, merge_mfargs(Opts, MFA)).
+
 %% @doc Open a UDP listener
--spec(open_udp(atom(), listen_on(), [option()], mfargs())
-     -> {ok, pid()}
-      | {error, term()}).
+-spec open_udp(atom(), listen_on(), [option()])
+      -> {ok, pid()} | {error, term()}.
+open_udp(Proto, Port, Opts) ->
+    esockd_sup:start_child(udp_child_spec(Proto, Port, Opts)).
+
+%% @doc Open a UDP listener
+-spec open_udp(atom(), listen_on(), [option()], mfargs())
+      -> {ok, pid()} | {error, term()}.
 open_udp(Proto, Port, Opts, MFA) ->
-    esockd_sup:start_child(udp_child_spec(Proto, Port, Opts, MFA)).
+    open_udp(Proto, Port, merge_mfargs(Opts, MFA)).
+
+%% @doc Open a DTLS listener
+-spec open_dtls(atom(), listen_on(), options())
+      -> {ok, pid()} | {error, term()}.
+open_dtls(Proto, ListenOn, Opts) ->
+    esockd_sup:start_child(dtls_child_spec(Proto, ListenOn, Opts)).
 
 %% @doc Open a DTLS listener
 -spec(open_dtls(atom(), listen_on(), options(), mfargs())
      -> {ok, pid()}
       | {error, term()}).
 open_dtls(Proto, ListenOn, Opts, MFA) ->
-    esockd_sup:start_child(dtls_child_spec(Proto, ListenOn, Opts, MFA)).
+    open_dtls(Proto, ListenOn, merge_mfargs(Opts, MFA)).
 
 %% @doc Close the listener
 -spec(close({atom(), listen_on()}) -> ok | {error, term()}).
@@ -179,22 +205,42 @@ reopen(Proto, ListenOn) when is_atom(Proto) ->
 
 %% @doc Create a Child spec for a TCP/SSL Listener. It is a convenient method
 %% for creating a Child spec to hang on another Application supervisor.
--spec(child_spec(atom(), listen_on(), [option()], mfargs())
-      -> supervisor:child_spec()).
+-spec child_spec(atom(), listen_on(), options())
+      -> supervisor:child_spec().
+child_spec(Proto, ListenOn, Opts) when is_atom(Proto) ->
+    esockd_sup:child_spec(Proto, fixaddr(ListenOn), Opts).
+
+-spec child_spec(atom(), listen_on(), options(), mfargs())
+      -> supervisor:child_spec().
 child_spec(Proto, ListenOn, Opts, MFA) when is_atom(Proto) ->
-    esockd_sup:child_spec(Proto, fixaddr(ListenOn), Opts, MFA).
+    child_spec(Proto, ListenOn, merge_mfargs(Opts, MFA)).
+
+%% @doc Create a Child spec for a UDP Listener.
+-spec udp_child_spec(atom(), listen_on(), options())
+     -> supervisor:child_spec().
+udp_child_spec(Proto, Port, Opts) ->
+    esockd_sup:udp_child_spec(Proto, fixaddr(Port), Opts).
 
 %% @doc Create a Child spec for a UDP Listener.
--spec(udp_child_spec(atom(), listen_on(), options(), mfargs())
-     -> supervisor:child_spec()).
+-spec udp_child_spec(atom(), listen_on(), options(), mfargs())
+     -> supervisor:child_spec().
 udp_child_spec(Proto, Port, Opts, MFA) ->
-    esockd_sup:udp_child_spec(Proto, fixaddr(Port), Opts, MFA).
+    udp_child_spec(Proto, Port, merge_mfargs(Opts, MFA)).
 
 %% @doc Create a Child spec for a DTLS Listener.
--spec(dtls_child_spec(atom(), listen_on(), options(), mfargs())
-     -> supervisor:child_spec()).
+-spec dtls_child_spec(atom(), listen_on(), options())
+     -> supervisor:child_spec().
+dtls_child_spec(Proto, ListenOn, Opts) ->
+    esockd_sup:dtls_child_spec(Proto, fixaddr(ListenOn), Opts).
+
+%% @doc Create a Child spec for a DTLS Listener.
+-spec dtls_child_spec(atom(), listen_on(), options(), mfargs())
+     -> supervisor:child_spec().
 dtls_child_spec(Proto, ListenOn, Opts, MFA) ->
-    esockd_sup:dtls_child_spec(Proto, fixaddr(ListenOn), Opts, MFA).
+    dtls_child_spec(Proto, ListenOn, merge_mfargs(Opts, MFA)).
+
+merge_mfargs(Opts, MFA) ->
+    [{connection_mfargs, MFA} | proplists:delete(connection_mfargs, Opts)].
 
 %%--------------------------------------------------------------------
 %% Get/Set APIs
@@ -279,6 +325,14 @@ deny({Proto, ListenOn}, CIDR) when is_atom(Proto) ->
 %%--------------------------------------------------------------------
 %% Utils
 
+-spec start_mfargs(mfargs(), _Arg1, _Arg2) -> _Ret.
+start_mfargs(M, A1, A2) when is_atom(M) ->
+    M:start_link(A1, A2);
+start_mfargs({M, F}, A1, A2) when is_atom(M), is_atom(F) ->
+    M:F(A1, A2);
+start_mfargs({M, F, Args}, A1, A2) when is_atom(M), is_atom(F), is_list(Args) ->
+    erlang:apply(M, F, [A1, A2 | Args]).
+
 %% @doc Merge two options
 -spec(merge_opts(proplists:proplist(), proplists:proplist())
       -> proplists:proplist()).

src/esockd_connection_sup.erl

@@ -18,9 +18,9 @@
 
 -behaviour(gen_server).
 
--import(proplists, [get_value/3]).
+-import(proplists, [get_value/3, get_value/2]).
 
--export([start_link/2, start_supervised/2, stop/1]).
+-export([start_link/1, start_supervised/1, stop/1]).
 
 -export([ start_connection/3
         , count_connections/1
@@ -67,16 +67,16 @@
         error_logger:error_msg("[~s] " ++ Format, [?MODULE | Args])).
 
 %% @doc Start connection supervisor.
--spec(start_link([esockd:option()], esockd:mfargs())
-      -> {ok, pid()} | ignore | {error, term()}).
-start_link(Opts, MFA) ->
-    gen_server:start_link(?MODULE, [Opts, MFA], []).
+-spec start_link([esockd:option()])
+      -> {ok, pid()} | ignore | {error, term()}.
+start_link(Opts) ->
+    gen_server:start_link(?MODULE, Opts, []).
 
--spec start_supervised(esockd:listener_ref(), esockd:mfargs())
+-spec start_supervised(esockd:listener_ref())
       -> {ok, pid()} | ignore | {error, term()}.
-start_supervised(ListenerRef, MFA) ->
+start_supervised(ListenerRef) ->
     Opts = esockd_server:get_listener_prop(ListenerRef, options),
-    case start_link(Opts, MFA) of
+    case start_link(Opts) of
         {ok, Pid} ->
             _ = esockd_server:set_listener_prop(ListenerRef, connection_sup, Pid),
             {ok, Pid};
@@ -113,14 +113,10 @@ start_connection(Sup, Sock, UpgradeFuns) ->
     end.
 
 %% @doc Start the connection process.
--spec(start_connection_proc(esockd:mfargs(), esockd_transport:socket())
-      -> {ok, pid()} | ignore | {error, term()}).
-start_connection_proc(M, Sock) when is_atom(M) ->
-    M:start_link(?TRANSPORT, Sock);
-start_connection_proc({M, F}, Sock) when is_atom(M), is_atom(F) ->
-    M:F(?TRANSPORT, Sock);
-start_connection_proc({M, F, Args}, Sock) when is_atom(M), is_atom(F), is_list(Args) ->
-    erlang:apply(M, F, [?TRANSPORT, Sock | Args]).
+-spec start_connection_proc(esockd:mfargs(), esockd_transport:socket())
+      -> {ok, pid()} | ignore | {error, term()}.
+start_connection_proc(MFA, Sock) ->
+    esockd:start_mfargs(MFA, ?TRANSPORT, Sock).
 
 -spec(count_connections(pid()) -> integer()).
 count_connections(Sup) ->
@@ -150,12 +146,13 @@ call(Sup, Req) ->
 %% gen_server callbacks
 %%--------------------------------------------------------------------
 
-init([Opts, MFA]) ->
+init(Opts) ->
     process_flag(trap_exit, true),
     Shutdown = get_value(shutdown, Opts, brutal_kill),
     MaxConns = get_value(max_connections, Opts, ?DEFAULT_MAX_CONNS),
     RawRules = get_value(access_rules, Opts, [{allow, all}]),
     AccessRules = [esockd_access:compile(Rule) || Rule <- RawRules],
+    MFA = get_value(connection_mfargs, Opts),
     {ok, #state{curr_connections = #{},
                 max_connections  = MaxConns,
                 access_rules     = AccessRules,
@@ -218,7 +215,8 @@ handle_call(get_options, _From, State) ->
     Options = [
         {shutdown, get_state_option(shutdown, State)},
         {max_connections, get_state_option(max_connections, State)},
-        {access_rules, get_state_option(access_rules, State)}
+        {access_rules, get_state_option(access_rules, State)},
+        {connection_mfargs, get_state_option(connection_mfargs, State)}
     ],
     {reply, Options, State};
 
@@ -280,7 +278,9 @@ get_state_option(max_connections, #state{max_connections = MaxConnections}) ->
 get_state_option(shutdown, #state{shutdown = Shutdown}) ->
     Shutdown;
 get_state_option(access_rules, #state{access_rules = Rules}) ->
-    [raw(Rule) || Rule <- Rules].
+    [raw(Rule) || Rule <- Rules];
+get_state_option(connection_mfargs, #state{mfargs = MFA}) ->
+    MFA.
 
 set_state_option({max_connections, MaxConns}, State) ->
     State#state{max_connections = MaxConns};
@@ -293,6 +293,8 @@ set_state_option({access_rules, Rules}, State) ->
     catch
         error:_Reason -> {error, bad_access_rules}
     end;
+set_state_option({connection_mfargs, MFA}, State) ->
+    State#state{mfargs = MFA};
 set_state_option(_, State) ->
     State.
 

src/esockd_listener_sup.erl

@@ -20,8 +20,7 @@
 
 -include("esockd.hrl").
 
--export([ start_link/5
-        , start_link/3
+-export([ start_link/2
         , listener/1
         , acceptor_sup/1
         , connection_sup/1
@@ -56,30 +55,16 @@
         , start_acceptors/1
         ]).
 
--type listen_type() :: tcp | dtls.
-
 %%--------------------------------------------------------------------
 %% APIs
 %%--------------------------------------------------------------------
 
 %% @doc Start listener supervisor
--spec start_link(listen_type(), atom(), esockd:listen_on(), [esockd:option()], esockd:mfargs())
-      -> {ok, pid()} | {error, term()}.
-start_link(Type, Proto, ListenOn, Opts, MFA) ->
-    %% NOTE
-    %% `Opts` are still part of the childspec, which means if whole listener supervisor
-    %% restarts, any changes done through `set_options` will be lost.
-    ListenerRef = {Proto, ListenOn},
-    _ = esockd_server:set_listener_prop(ListenerRef, type, Type),
-    _ = esockd_server:set_listener_prop(ListenerRef, options, Opts),
-    supervisor:start_link(?MODULE, {ListenerRef, MFA}).
-
-%% @doc Start listener supervisor
--spec start_link(atom(), esockd:listen_on(), esockd:mfargs())
+-spec start_link(atom(), esockd:listen_on())
       -> {ok, pid()} | {error, term()}.
-start_link(Proto, ListenOn, MFA) ->
+start_link(Proto, ListenOn) ->
     ListenerRef = {Proto, ListenOn},
-    supervisor:start_link(?MODULE, {ListenerRef, MFA}).
+    supervisor:start_link(?MODULE, ListenerRef).
 
 %% @doc Get listener.
 -spec(listener(pid()) -> {module(), pid()}).
@@ -181,9 +166,9 @@ deny(Sup, CIDR) ->
 %% Supervisor callbacks
 %%--------------------------------------------------------------------
 
-init({ListenerRef, MFA}) ->
+init(ListenerRef) ->
     ConnSup = #{id => connection_sup,
-                start => {esockd_connection_sup, start_supervised, [ListenerRef, MFA]},
+                start => {esockd_connection_sup, start_supervised, [ListenerRef]},
                 restart => transient,
                 shutdown => infinity,
                 type => supervisor,