Cannot re-enable rabbitmq_web_stomp plugin after disabling it

[kpe]

Stopping the web_stomp plugin fails (while rabbitmq is running), e.g. doing

rabbitmq-plugins enable  rabbitmq_web_stomp
rabbitmq-plugins disable rabbitmq_web_stomp
rabbitmq-plugins enable  rabbitmq_web_stomp

fails with

Error: {could_not_start,rabbitmq_web_stomp,
       {{badmatch,{error,{already_started,<10343.424.0>}}},
        [{rabbit_ws_sockjs,init,0,
             [{file,"src/rabbit_ws_sockjs.erl"},{line,51}]},
         {rabbit_ws_app,start,2,
             [{file,"src/rabbit_ws_app.erl"},{line,26}]},
         {application_master,start_it_old,4,
             [{file,"application_master.erl"},{line,273}]}]}}

in similar fashion

rabbitmqctl stop_app
rabbitmqctl start_app

fails with the same "sockjs is aready started" error.

I'm not sure however if that's sockjs, webstomp or rabbitmq error. This was working with rabbitmq 3.6.3, but seems to be broken since 3.6.8 at least.

My rabbitmq.config looks like this:

[
 {ssl, [{versions, ['tlsv1.2','tlsv1.1']}]},
 {rabbit, [
           {vm_memory_high_watermark, {absolute, "4096MiB"}},
          {tcp_listeners, [5672]},
          {ssl_listeners, [5671]},
          {ssl_options, [{cacertfile, "/etc/rabbitmq/cacert.pem"},
                         {certfile,   "/etc/rabbitmq/cert.pem"},
                         {keyfile,    "/etc/rabbitmq/key.pem"},
                         {verify,verify_peer},
                         {fail_if_no_peer_cert,true},
                         {versions, ['tlsv1.2']}
                        ]},
          {loopback_users, []},
          {cluster_nodes, {[],disc}}
         ]
},
{rabbitmq_web_stomp,
 [{tcp_config, []},
  {ssl_config, [{port, 15691},
                {backlog, 1024},
                {cacertfile, "/etc/rabbitmq/cacert.pem"},
                {certfile,   "/etc/rabbitmq/cert.pem"},
                {keyfile,    "/etc/rabbitmq/key.pem"},
                {password, ""},
                {verify,verify_none},
                {fail_if_no_peer_cert,false}
               ]}]
},    
{rabbitmq_management,
 [{listener, [{port, 15672},
              {ssl, true},
              {ssl_opts, [{cacertfile, "/etc/rabbitmq/cacert.pem"},
                          {certfile,   "/etc/rabbitmq/cert.pem"},
                          {keyfile,    "/etc/rabbitmq/key.pem"}]}
             ]}]
 }
].

[michaelklishin]

I can reproduce.

You can do two things to wrk around:

• Edit RabbitMQ's enabled_plugins file (it's an Erlang list, just delete rabbitmq_web_stomp from it, then the node will start)
• Run rabbitmqctl eval 'cowboy:stop_listener(http).' after disabling the plugin

[michaelklishin]

@essen I have a workaround but still curious: when this plugin is disabled, should we stop the listener? If so, what'd be the right (and safe) way to do it?

[michaelklishin]

To clarify: I'm not sure if we can safely stop the listener in case there are more plugins using HTTP enabled. Plugins should unbind from the ports they use, of course.