Mqtt discovery optional nodeid (home-assistant#2840)

AlexMekkering · balloob · commit 55bec87b3865 · 2017-06-24T00:47:13.000-07:00
* Add support for remote (TCP/IP) DSMR sensors (i.e. via ser2net)

* Processed review comment and added ser2net config

* added optional node_id to MQTT discovery
diff --git a/source/_docs/mqtt/discovery.markdown b/source/_docs/mqtt/discovery.markdown
@@ -37,15 +37,18 @@ Configuration variables:
 The discovery topic need to follow a specific format:
 
 ```text
-<discovery_prefix>/<component>/<object_id>/<>
+<discovery_prefix>/<component>/[<node_id>/]<object_id>/<>
 ```
 
 - `<component>`: One of the supported components, eg. `binary_sensor`.
+- `<node_id>`: (*Optional*) id of the node providing the topic.
 - `<object_id>`: The ID of the device. This will become the `entity_id` in Home Assistant.
 - `<>`: The topic `config` or `state` which defines the current action.
 
 The payload will be checked like an entry in your `configuration.yaml` file if a new device is added. This means that missing variables will be filled with the platform's default values. All configuration variables which are *required* must be present in the initial payload send to `/config`.
 
+The `<node_id>` level can be used by clients to only subscribe to their own (command) topics by using one wildcard topic like `<discovery_prefix>/+/<node_id>/+/set`.
+
 ### {% linkable_title Examples %}
 
 A motion detection device which can be represented by a [binary sensor](/components/binary_sensor.mqtt/) for your garden would sent its configuration as JSON payload to the Configuration topic. After the first message to `config`, then the MQTT messages sent to the state topic will update the state in Home Assistant.
