add start_link variants

Author: james

src/gen_smtp_server.erl

@@ -30,37 +30,53 @@
 
 %% External API
 -export([
-    start/3, start/2, start/1,
-    stop/1,
-    child_spec/3,
-    sessions/1
-]).
+         start_link/1, start_link/2, start_link/3,
+         start/3, start/2, start/1,
+         stop/1,
+         child_spec/3,
+         sessions/1
+        ]).
 -export_type([options/0]).
 
 -type server_name() :: any().
 -type options() ::
-    [
-        {domain, string()}
+        [
+         {domain, string()}
         | {address, inet:ip4_address()}
         | {family, inet | inet6}
         | {port, inet:port_number()}
         | {protocol, 'tcp' | 'ssl'}
         | {ranch_opts, ranch:opts()}
         | {sessionoptions, gen_smtp_server_session:options()}
-    ].
+        ].
+
+%% @doc Start the listener as a registered process with callback module `Module' on with options `Options' linked to the calling process.
+-spec start_link(ServerName :: {'local', atom()} | {'global', any()}, Module :: atom(), Options :: [options()]) -> {'ok', pid()} | 'ignore' | {'error', any()}.
+start_link(ServerName, Module, Options) when is_list(Options) ->
+    gen_server:start_link(ServerName, ?MODULE, [Module, Options], []).
+
+%% @doc Start the listener with callback module `Module' on with options `Options' linked to the calling process.
+-spec start_link(Module :: atom(), Options :: [options()]) -> {'ok', pid()} | 'ignore' | {'error', any()}.
+start_link(Module, Options) when is_list(Options) ->
+    gen_server:start_link(?MODULE, [Module, Options], []).
+
+%% @doc Start the listener with callback module `Module' with default options linked to the calling process.
+-spec start_link(Module :: atom()) -> {'ok', pid()} | 'ignore' | {'error', any()}.
+start_link(Module) ->
+    start_link(Module, [[]]).
 
 %% @doc Start the listener as a registered process with callback module `Module' with options `Options' linked to no process.
 -spec start(
-    ServerName :: server_name(),
-    CallbackModule :: module(),
-    Options :: options()
-) -> {'ok', pid()} | {'error', any()}.
+        ServerName :: server_name(),
+        CallbackModule :: module(),
+        Options :: options()
+       ) -> {'ok', pid()} | {'error', any()}.
 start(ServerName, CallbackModule, Options) when is_list(Options) ->
     case convert_options(CallbackModule, Options) of
         {ok, Transport, TransportOpts, ProtocolOpts} ->
             ranch:start_listener(
-                ServerName, Transport, TransportOpts, gen_smtp_server_session, ProtocolOpts
-            );
+              ServerName, Transport, TransportOpts, gen_smtp_server_session, ProtocolOpts
+             );
         {error, Reason} ->
             {error, Reason}
     end.
@@ -69,12 +85,12 @@ child_spec(ServerName, CallbackModule, Options) ->
     case convert_options(CallbackModule, Options) of
         {ok, Transport, TransportOpts, ProtocolOpts} ->
             ranch:child_spec(
-                ServerName, Transport, TransportOpts, gen_smtp_server_session, ProtocolOpts
-            );
+              ServerName, Transport, TransportOpts, gen_smtp_server_session, ProtocolOpts
+             );
         {error, Reason} ->
-            % `supervisor:child_spec' is not compatible with ok/error tuples.
-            % This error is likely to occur when starting the application,
-            % so the user can sort out the configuration parameters and try again.
+                                                % `supervisor:child_spec' is not compatible with ok/error tuples.
+                                                % This error is likely to occur when starting the application,
+                                                % so the user can sort out the configuration parameters and try again.
             erlang:error(Reason)
     end.
 
@@ -93,31 +109,31 @@ convert_options(CallbackModule, Options) ->
     case {EmailTransferProtocol, Port} of
         {lmtp, 25} ->
             ?LOG_ERROR("LMTP is different from SMTP, it MUST NOT be used on the TCP port 25", #{
-                domain => [gen_smtp, server]
-            }),
-            % Error defined in section 5 of https://tools.ietf.org/html/rfc2033
+                                                                                                domain => [gen_smtp, server]
+                                                                                               }),
+                                                % Error defined in section 5 of https://tools.ietf.org/html/rfc2033
             {error, invalid_lmtp_port};
         _ ->
             ProtocolOpts1 = {CallbackModule, [{hostname, Hostname} | ProtocolOpts]},
             RanchOpts = proplists:get_value(ranch_opts, Options, #{}),
             SocketOpts = maps:get(socket_opts, RanchOpts, []),
             TransportOpts = RanchOpts#{
-                socket_opts =>
-                    [
-                        {port, Port},
-                        {ip, Address},
-                        {keepalive, true},
-                        %% binary, {active, false}, {reuseaddr, true} - ranch defaults
-                        Family
-                        | SocketOpts
-                    ]
-            },
+                                       socket_opts =>
+                                           [
+                                            {port, Port},
+                                            {ip, Address},
+                                            {keepalive, true},
+                                            %% binary, {active, false}, {reuseaddr, true} - ranch defaults
+                                            Family
+                                           | SocketOpts
+                                           ]
+                                      },
             {ok, Transport, TransportOpts, ProtocolOpts1}
     end.
 
 %% @doc Start the listener with callback module `Module' with options `Options' linked to no process.
 -spec start(CallbackModule :: module(), Options :: options()) ->
-    {'ok', pid()} | 'ignore' | {'error', any()}.
+          {'ok', pid()} | 'ignore' | {'error', any()}.
 start(CallbackModule, Options) when is_list(Options) ->
     start(?MODULE, CallbackModule, Options).