erlang - ejabberd - module gen_mod & gen_server with RabbitMq -

i'm developing ejabberd module can send queue directly rabbitmq using ejabberd hook gen_mod behaviour. queue can sent without issue. however, connection rabbitmq server not persistent.

sample working code per following :

-module(mod_rab). -author('author@domain.com').  -behaviour(gen_mod).  -export([start/2,      init/2,      stop/1,      send_available_notice/4]).  -define(procname, ?module).  -include("ejabberd.hrl"). -include("jlib.hrl"). -include("logger.hrl"). -include("amqp_client.hrl").  start(host, opts) ->     ?info_msg("starting mod_rab testing", [] ),     register(?procname,spawn(?module, init, [host, opts])),       ok.  init(host, _opts) ->     inets:start(),     ssl:start(),     ejabberd_hooks:add(set_presence_hook, host, ?module, send_available_notice, 10),     ok.  stop(host) ->     ?info_msg("stopping mod_rab testing", [] ),     ejabberd_hooks:delete(set_presence_hook, host,               ?module, send_available_notice, 10),     ok.  send_available_notice(user, server, _resource, _packet) ->     {ok, connection} =         amqp_connection:start(#amqp_params_network{host = "localhost"}),     {ok, channel} = amqp_connection:open_channel(connection),      amqp_channel:call(channel, #'queue.declare'{queue = <<"hello">>}),      amqp_channel:cast(channel,                       #'basic.publish'{                         exchange = <<"">>,                         routing_key = <<"hello">>},                       #amqp_msg{payload = <<"hello world!">>}),     io:format(" [x] sent 'hello world!'~n"),     ok = amqp_channel:close(channel),     ok = amqp_connection:close(connection),     ok. 

i've tried use gen_server create persistent connection , should able use when hook triggered. if understand gen_server correctly, keep connection in state , use during hook callback.

broken code i've tried before :

-module(mod_rab). -author('author@domain.com').  -behaviour(gen_mod). -behaviour(gen_server).  -export([start/2,      init/2,      stop/1,      send_available_notice/4]).   -export([start_link/1]).   -export([handle_call/3, handle_cast/2, handle_info/2,          terminate/2, code_change/3]).   -define(procname, ?module).  -record(state, {channel, connection}).  -include("ejabberd.hrl"). -include("jlib.hrl"). -include("logger.hrl"). -include("amqp_client.hrl").  start_link(opts) ->     gen_server:start_link({local, ?module}, ?module, opts, []).   start(host, opts) ->     ?info_msg("starting mod_rab testing", [] ),          inets:start(),     ssl:start(),          ejabberd_hooks:add(set_presence_hook, host, ?module, send_available_notice, 10),          {ok, connection} =                 amqp_connection:start(#amqp_params_network{ host = "localhost"),         {ok, channel} = amqp_connection:open_channel(connection),     ?info_msg("channel ~s", [channel] ),         {ok, #state{ connection = connection, channel = channel}},  %%    register(?procname,spawn(?module, init, [host, opts])),     ok.  init(host, _opts) ->      ok.  stop(host) ->     ?info_msg("stopping mod_rab testing", [] ),      ejabberd_hooks:delete(set_presence_hook, host,               ?module, send_available_notice, 10),     ok.    send_available_notice(user, server,_resource, _packet) ->       ?info_msg("hook", [] ),      amqp_channel:call(#state.channel, #'queue.declare'{queue = <<"hello">>}),      amqp_channel:cast(channel,                       #'basic.publish'{                         exchange = <<"">>,                         routing_key = <<"hello">>},                       #amqp_msg{payload = <<"hello world!">>}),     io:format(" [x] sent 'hello world!'~n"),          ?info_msg("sent", [] ),  %%      ok = amqp_channel:close(channel), %%      ok = amqp_connection:close(connection),      ok.  handle_call(_request, _from, state) ->     reply = ok,     {reply, reply, state}.  handle_cast(send_available_notice, state) ->     {noreply, state}.  handle_info(_info, state) ->     {noreply, state}.  terminate(_reason, _state) ->             ok.  code_change(_oldvsn, state, _extra) ->                 {ok, state}. 

thanks help