Implements the Divo Stack behaviour to take a keyword list of defined variables specific to the DivoVernemq stack and returns a map describing the service definition of VerneMQ.

Optional Configuration

• allow_anonymous: Allow unauthenticated connections to the cluster. Defaults to :on

• mqtt_port: The port on which the MQTT listener will be exposed to the host. The default

           port VerneMQ uses for MQTT is 1883. The only affects the port exposed to the host;
           within the container the VerneMQ broker is listening on port 1883.

• ssl_mqtt_port: The port on which the MQTT over SSL communication will be exposed to the host.

               The default port VerneMQ uses for MQTT over SSL is 8883. This only affects the
               port exposed to the host; within the container, the VerneMQ broker is listening
               on port 8883.

• ws_mqtt_port: The port on which the MQTT over Websocket communication will be exposed to the host.

              The default port VerneMQ uses for MQTT over websockets is 8080. This only
              affects the port exposed to the host; within the container the VerneMQ broker
              is listening on port 8080.

• stats_port: The port on which the statistics web service, including the status UI, is exposed

            to the host. The default port VerneMQ uses for the stats interface is 8888. This
            only affects the host port; within the container the VerneMQ broker is listening on
            port 8888. Set your browser to `localhost:<stats_port>/status` to view the UI.

• log_level: The log level at which the VerneMQ broker will output messages. Defaults to :info.

• users: A map of usernames and passwords to create records for file-based authentication. These

      are transparently converted to environment variables that are injected into the container
      in the form of `DOCKER_VERNEMQ_USER_<username>='password'`. Defaults to an empty map.

• version: The version of the VerneMQ image to run. Defaults to latest.