Compile:

mkdir ebin
erlc -o ebin/ -I /usr/local/src/ejabberd-xxx/include/ -DLAGER -DNO_EXT_LIB src/mod_prometheus.erl

Copy compiled file to ejabberd, for example:

cp ebin/mod_prometheus.beam /usr/local/lib/ejabberd-xxx/ebin/

Add config to ejabberd.yml:

listen:
  -
    port: 8181
    module: ejabberd_http
    request_handlers:
      "/metrics": mod_prometheus

Restart ejabberd:

ejabberdctl restart

Test metrics:

visit http://localhost:8181/metrics in browser or exec curl localhost:8181/metrics in cli.

You have to see metrics for prometheus. Service will respond all requests independently request type and request path.

Support Metrics List:

• total_run_queue_lengths
• total_active_tasks
• context_switches
• garbage_collection
• io
• reductions
• runtime
• allocated_areas
• port_count
• port_limit
• process_count
• process_limit
• connected_users
• registered_users
• muc_online_rooms