Don't include max_connections into socket options

It is rejected as an unsupported value.
Use Ranch transport options directly instead.

References #28.
Closes #55.

Author: michaelklishin

priv/schema/rabbitmq_web_mqtt.schema

@@ -2,6 +2,9 @@
     [{datatype, integer}]}.
 {mapping, "web_mqtt.num_acceptors.ssl", "rabbitmq_web_mqtt.num_ssl_acceptors",
     [{datatype, integer}]}.
+{mapping, "web_mqtt.max_connections", "rabbitmq_web_mqtt.max_connections", [
+    {datatype, [{enum, [infinity]}, integer]}
+]}.
 
 {mapping, "web_mqtt.tcp.backlog", "rabbitmq_web_mqtt.tcp_config.backlog",
     [{datatype, integer}]}.
@@ -12,9 +15,6 @@
     [{datatype, string}, {validators, ["is_ip"]}]}.
 {mapping, "web_mqtt.tcp.port", "rabbitmq_web_mqtt.tcp_config.port",
     [{datatype, integer}]}.
-{mapping, "web_mqtt.tcp.max_connections", "rabbitmq_web_mqtt.tcp_config.max_connections", [
-    {datatype, [{enum, [infinity]}, integer]}
-]}.
 
 {mapping, "web_mqtt.ws_path", "rabbitmq_web_mqtt.ws_path",
     [{datatype, string}]}.

src/rabbit_web_mqtt_app.erl

@@ -66,8 +66,9 @@ mqtt_init() ->
 
 start_tcp_listener(TCPConf0, CowboyOpts) ->
   {TCPConf, IpStr, Port} = get_tcp_conf(TCPConf0),
+  MaxConnections = get_max_connections(),
   case ranch:start_listener(web_mqtt, get_env(num_tcp_acceptors, 10),
-      ranch_tcp, TCPConf,
+      ranch_tcp, [{max_connections, MaxConnections}|TCPConf],
       rabbit_web_mqtt_connection_sup, CowboyOpts) of
       {ok, _}                       -> ok;
       {error, {already_started, _}} -> ok;
@@ -85,11 +86,12 @@ start_tcp_listener(TCPConf0, CowboyOpts) ->
 start_tls_listener(TLSConf0, CowboyOpts) ->
   rabbit_networking:ensure_ssl(),
   {TLSConf, TLSIpStr, TLSPort} = get_tls_conf(TLSConf0),
+  MaxConnections = get_max_connections(),
   {ok, _} = ranch:start_listener(web_mqtt_secure, get_env(num_ssl_acceptors, 10),
-      ranch_ssl, TLSConf,
+      ranch_ssl, [{max_connections, MaxConnections}|TLSConf],
       rabbit_web_mqtt_connection_sup, CowboyOpts),
   case ranch:start_listener(web_mqtt_secure, get_env(num_ssl_acceptors, 10),
-      ranch_ssl, TLSConf,
+      ranch_ssl, [{max_connections, MaxConnections}|TLSConf],
       rabbit_web_mqtt_connection_sup, CowboyOpts) of
       {ok, _}                       -> ok;
       {error, {already_started, _}} -> ok;
@@ -113,19 +115,15 @@ listener_started(Protocol, Listener) ->
     ok.
 
 get_tcp_conf(TCPConf0) ->
-    TCPConf1 = [{connection_type, supervisor},
-                %% see rabbitmq/rabbitmq-web-mqtt#28 for background
-                {max_connections, infinity}] ++ TCPConf0,
+    TCPConf1 = [{connection_type, supervisor}|TCPConf0],
     TCPConf2 = case proplists:get_value(port, TCPConf1) of
                    undefined -> [{port, 15675}|TCPConf1];
                    _ -> TCPConf1
                end,
     get_ip_port(TCPConf2).
 
 get_tls_conf(TLSConf0) ->
-    TLSConf1 = [{connection_type, supervisor},
-                %% see rabbitmq/rabbitmq-web-mqtt#28 for background
-                {max_connections, infinity}] ++ TLSConf0,
+    TLSConf1 = [{connection_type, supervisor}|TLSConf0],
     TLSConf2 = case proplists:get_value(port, TLSConf1) of
                    undefined -> [{port, 15675}|proplists:delete(port, TLSConf1)];
                    _ -> TLSConf1
@@ -145,5 +143,8 @@ normalize_ip(IpStr) when is_list(IpStr) ->
 normalize_ip(Ip) ->
     Ip.
 
+get_max_connections() ->
+  get_env(max_connections, infinity).
+
 get_env(Key, Default) ->
     rabbit_misc:get_env(rabbitmq_web_mqtt, Key, Default).

test/config_schema_SUITE_data/rabbitmq_web_mqtt.snippets

@@ -29,10 +29,23 @@
   [{rabbitmq_web_mqtt,
     [{tcp_config, [{port,34567}]}]}],
   [rabbitmq_web_mqtt]},
-  {tcp_config_max_connections,
-   "web_mqtt.tcp.max_connections = 5000",
+
+ {num_acceptors_tcp,
+   "web_mqtt.num_acceptors.tcp = 20",
+   [{rabbitmq_web_mqtt,
+     [{num_tcp_acceptors, 20}]}],
+   [rabbitmq_web_mqtt]},
+
+ {num_acceptors_tls,
+  "web_mqtt.num_acceptors.ssl = 20",
+  [{rabbitmq_web_mqtt,
+    [{num_ssl_acceptors, 20}]}],
+  [rabbitmq_web_mqtt]},
+
+  {max_connections,
+   "web_mqtt.max_connections = 5000",
    [{rabbitmq_web_mqtt,
-     [{tcp_config, [{max_connections, 5000}]}]}],
+     [{max_connections, 5000}]}],
    [rabbitmq_web_mqtt]},
 
  {ssl_listener,