Non-AMQP exit reason '{shutdown,badarg}'

[razvanphp]

Describe the bug

I'm writing a simple plugin for the OCPP protocol, very similar to rabbit_web_mqtt, since it handles the data over websocket as well and I got into a problem I can't fix no matter how many hours I try, please help an Erlang beginner 🙂

Reproduction steps

1. I'm using the mc pattern to build the mc_ocpp resource.
2. Here is the relevant code:

%% Only for AMQP 0-9-1
convert_to(mc_amqpl,
           #ocpp_msg{payload = Payload,
                     msg_id   = MsgId,
                     action   = Action,
                     client_id= ClientId},
           _Env) ->
    %% 1) Build the basic properties record
    BP = #'P_basic'{
      delivery_mode   = 1,                % non-persistent
      correlation_id  = MsgId,            % your OCPP msg_id
      type            = Action,           % maps to 'type' header
      content_type    = ?CONTENT_TYPE_JSON,
      reply_to        = ClientId,         % OCPP client_id
      headers         = undefined         % no extra field-table entries
    },

    %% 2) Wrap the JSON payload as a single binary
    PFR = [ iolist_to_binary(Payload) ],

    %% 3) Use the Basic class ID (60) for content frames
    #content{
      class_id              = 60,
      properties            = BP,
      properties_bin        = none,
      payload_fragments_rev = PFR
    };

3. The error happens only when there is an AMQP 0-9-1 client about to receive it, when no conversion happens, the message is received correctly.
4. I added a stack trace for debugging this edge case in:
   

   rabbitmq-server/deps/rabbit_common/src/rabbit_binary_generator.erl

   Line 226 in a43e2c5

   rabbit_log:warning("Non-AMQP exit reason '~tp'", [Other]),

   
   but it's not so helpful, as I still can't understand where the badarg comes from...

2025-07-17 17:29:07.540241+03:00 [error] <0.900.0> Error on AMQP connection <0.900.0> (127.0.0.1:52978 -> 127.0.0.1:5672, vhost: '/', user: 'guest', state: running), channel 1:
2025-07-17 17:29:07.540241+03:00 [error] <0.900.0>  {shutdown,badarg}
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0> Non-AMQP exit reason '{shutdown,badarg}'. Stack trace: [{rabbit_binary_generator,
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                          lookup_amqp_exception,
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                          2,
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                          [{file,
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                            "rabbit_binary_generator.erl"},
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                           {line,228}]},
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                         {rabbit_binary_generator,
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                          map_exception,3,
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                          [{file,
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                            "rabbit_binary_generator.erl"},
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                           {line,201}]},
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                         {rabbit_reader,
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                          send_error_on_channel0_and_close,
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                          4,
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                          [{file,
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                            "rabbit_reader.erl"},
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                           {line,1679}]},
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                         {rabbit_reader,
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                          mainloop,4,
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                          [{file,
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                            "rabbit_reader.erl"},
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                           {line,553}]},
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                         {rabbit_reader,run,1,
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                          [{file,
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                            "rabbit_reader.erl"},
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                           {line,475}]},
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                         {rabbit_reader,
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                          start_connection,5,
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                          [{file,
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                            "rabbit_reader.erl"},
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                           {line,355}]},
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                         {proc_lib,
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                          init_p_do_apply,3,
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                          [{file,
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                            "proc_lib.erl"},
2025-07-17 17:29:07.541049+03:00 [error] <0.900.0>                                                           {line,329}]}]
2025-07-17 17:29:07.542236+03:00 [error] <0.900.0> Error on AMQP connection <0.900.0> (127.0.0.1:52978 -> 127.0.0.1:5672, vhost: '/', user: 'guest', state: running), channel 1:error while terminating:
2025-07-17 17:29:07.542236+03:00 [error] <0.900.0> shutdown
2025-07-17 17:29:07.543642+03:00 [info] <0.900.0> closing AMQP connection (127.0.0.1:52978 -> 127.0.0.1:5672, vhost: '/', user: 'guest', duration: '5s')

Expected behavior

Explicit stack trace to where the error happens in AMQP framing or where the bad argument error is thrown.

Additional context

No response

[razvanphp]

Hmm, managed to catch it, very tricky one: The exchange field in a basic.deliver frame must be a binary string, not an internal resource tuple.

2025-07-17 19:18:04.329182+03:00 [debug] <0.904.0> rabbit_writer: internal_send_command_async with Method: {'basic.deliver',
2025-07-17 19:18:04.329182+03:00 [debug] <0.904.0>                                                          <<"amq.ctag-KviTTVUQlZkizYlujg9Hag">>,
2025-07-17 19:18:04.329182+03:00 [debug] <0.904.0>                                                          1,false,
2025-07-17 19:18:04.329182+03:00 [debug] <0.904.0>                                                          {resource,<<"/">>,
2025-07-17 19:18:04.329182+03:00 [debug] <0.904.0>                                                           exchange,
2025-07-17 19:18:04.329182+03:00 [debug] <0.904.0>                                                           <<"amq.topic">>},
2025-07-17 19:18:04.329182+03:00 [debug] <0.904.0>                                                          <<"guest">>}, Content: {content,
2025-07-17 19:18:04.329182+03:00 [debug] <0.904.0>                                                                                  60,
2025-07-17 19:18:04.329182+03:00 [debug] <0.904.0>                                                                                  {'P_basic',
2025-07-17 19:18:04.329182+03:00 [debug] <0.904.0>                                                                                   <<"application/json">>,
2025-07-17 19:18:04.329182+03:00 [debug] <0.904.0>                                                                                   undefined,
2025-07-17 19:18:04.329182+03:00 [debug] <0.904.0>                                                                                   undefined,
2025-07-17 19:18:04.329182+03:00 [debug] <0.904.0>                                                                                   1,
2025-07-17 19:18:04.329182+03:00 [debug] <0.904.0>                                                                                   undefined,
2025-07-17 19:18:04.329182+03:00 [debug] <0.904.0>                                                                                   <<" 15455 ">>,
2025-07-17 19:18:04.329182+03:00 [debug] <0.904.0>                                                                                   <<"guest">>,
2025-07-17 19:18:04.329182+03:00 [debug] <0.904.0>                                                                                   undefined,
2025-07-17 19:18:04.329182+03:00 [debug] <0.904.0>                                                                                   undefined,
2025-07-17 19:18:04.329182+03:00 [debug] <0.904.0>                                                                                   undefined,
2025-07-17 19:18:04.329182+03:00 [debug] <0.904.0>                                                                                   undefined,
2025-07-17 19:18:04.329182+03:00 [debug] <0.904.0>                                                                                   undefined,
2025-07-17 19:18:04.329182+03:00 [debug] <0.904.0>                                                                                   undefined,
2025-07-17 19:18:04.329182+03:00 [debug] <0.904.0>                                                                                   undefined},
2025-07-17 19:18:04.329182+03:00 [debug] <0.904.0>                                                                                  none,
2025-07-17 19:18:04.329182+03:00 [debug] <0.904.0>                                                                                  undefined,
2025-07-17 19:18:04.329182+03:00 [debug] <0.904.0>                                                                                  [<<"[3,\" 15455 \",{\"currentTime\":\"2022-12-02T15:08:43.882Z\",\"interval\":60,\"status\":\"Accepted\"}]">>]}
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0> Crash in rabbit_writer:internal_send_command_async on channel 1: error:badarg
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0> Method: {'basic.deliver',<<"amq.ctag-KviTTVUQlZkizYlujg9Hag">>,1,false,
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>                          {resource,<<"/">>,exchange,<<"amq.topic">>},
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>                          <<"guest">>}
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0> Content: {content,60,
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>                   {'P_basic',<<"application/json">>,undefined,undefined,1,
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>                              undefined,<<" 15455 ">>,<<"guest">>,undefined,
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>                              undefined,undefined,undefined,undefined,
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>                              undefined,undefined},
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>                   none,undefined,
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>                   [<<"[3,\" 15455 \",{\"currentTime\":\"2022-12-02T15:08:43.882Z\",\"interval\":60,\"status\":\"Accepted\"}]">>]}
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0> Stacktrace: [{rabbit_framing_amqp_0_9_1,encode_method_fields,1,
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>                  [{file,"rabbit_framing_amqp_0_9_1.erl"},
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>                   {line,991},
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>                   {error_info,
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>                       #{cause =>
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>                             {6,binary,type,
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>                              {resource,<<"/">>,exchange,<<"amq.topic">>}},
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>                         function => format_bs_fail,
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>                         module => erl_erts_errors}}]},
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>              {rabbit_binary_generator,build_simple_method_frame,3,
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>                  [{file,"rabbit_binary_generator.erl"},{line,50}]},
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>              {rabbit_writer,assemble_frames,5,
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>                  [{file,"rabbit_writer.erl"},{line,334}]},
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>              {rabbit_writer,internal_send_command_async,3,
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>                  [{file,"rabbit_writer.erl"},{line,370}]},
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>              {rabbit_writer,handle_message,2,
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>                  [{file,"rabbit_writer.erl"},{line,256}]},
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>              {rabbit_writer,handle_info,2,
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>                  [{file,"rabbit_writer.erl"},{line,233}]},
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>              {gen_server,try_handle_info,3,
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>                  [{file,"gen_server.erl"},{line,2345}]},
2025-07-17 19:18:04.329537+03:00 [error] <0.904.0>              {gen_server,handle_msg,6,[{file,"gen_server.erl"},{line,2433}]}]
2025-07-17 19:18:04.330018+03:00 [error] <0.899.0> mainloop: received {other,{channel_exit,1,{shutdown,badarg}}} on connection 127.0.0.1:59143 -> 127.0.0.1:5672
2025-07-17 19:18:04.330070+03:00 [error] <0.899.0> Error on AMQP connection <0.899.0> (127.0.0.1:59143 -> 127.0.0.1:5672, vhost: '/', user: 'guest', state: running), channel 1:
2025-07-17 19:18:04.330070+03:00 [error] <0.899.0>  connection shutdown with reason badarg

Maybe I could add a catch clause for this case so others don't waste hours debugging this...