feat(mqtt): scope discovery topics and unique_ids by MQTT namespace

Author: brianmay

lib/teslamate/mqtt/pubsub/home_assistant.ex

@@ -27,26 +27,27 @@ defmodule TeslaMate.Mqtt.PubSub.HomeAssistant do
   the given vehicle summary.
 
   Each payload is published retained (QoS 1) to
-  `<discovery_prefix>/<component>/<node>_<car_id>/<object_id>/config` where
-  `node` is `#{@node}`. Returns `:ok` on success.
+  `<discovery_prefix>/<component>/<node>/<object_id>/config` where `node` is
+  `#{@node}_<car_id>` (with the `MQTT_NAMESPACE` inserted after `#{@node}`
+  when set). Returns `:ok` on success.
   """
   @spec publish(term(), publish_opts(), term()) :: :ok | {:error, term()}
   def publish(%Summary{} = summary, opts, publisher) do
     car_id = Keyword.fetch!(opts, :car_id)
     namespace = Keyword.get(opts, :namespace)
     base_url = Keyword.get(opts, :base_url)
     prefix = Keyword.get(opts, :discovery_prefix, @discovery_prefix)
-    node = "#{@node}_#{car_id}"
+    node = node(car_id, namespace)
 
-    device = device(summary, car_id, base_url)
+    device = device(summary, car_id, base_url, namespace)
 
     Enum.reduce_while(entities(), :ok, fn {component, object_id, config}, _acc ->
       topic = discovery_topic(prefix, component, node, object_id)
 
       payload =
         config
         |> resolve_topics(car_id, namespace)
-        |> Map.put(:unique_id, "teslamate_#{car_id}_#{object_id}")
+        |> Map.put(:unique_id, "#{node}_#{object_id}")
         |> Map.put(:object_id, "tesla_#{object_id}")
         |> Map.put(:device, device)
         |> Jason.encode!()
@@ -65,8 +66,9 @@ defmodule TeslaMate.Mqtt.PubSub.HomeAssistant do
   """
   @spec clear(pos_integer(), publish_opts(), term()) :: :ok | {:error, term()}
   def clear(car_id, opts, publisher) do
+    namespace = Keyword.get(opts, :namespace)
     prefix = Keyword.get(opts, :discovery_prefix, @discovery_prefix)
-    node = "#{@node}_#{car_id}"
+    node = node(car_id, namespace)
 
     Enum.reduce_while(entities(), :ok, fn {component, object_id, _config}, _acc ->
       topic = discovery_topic(prefix, component, node, object_id)
@@ -109,14 +111,29 @@ defmodule TeslaMate.Mqtt.PubSub.HomeAssistant do
     |> Enum.join("/")
   end
 
-  defp device(%Summary{} = summary, car_id, base_url) do
+  defp node(car_id, namespace) do
+    [@node, namespace, car_id]
+    |> Enum.reject(&is_nil/1)
+    |> Enum.join("_")
+  end
+
+  defp device(%Summary{} = summary, car_id, base_url, namespace) do
     name = summary.display_name || car_name(summary) || "Tesla ##{car_id}"
     model = summary.model || "Tesla"
 
-    %{identifiers: ["teslamate_car_#{car_id}"], manufacturer: "Tesla", name: name, model: model}
+    %{
+      identifiers: [device_identifier(car_id, namespace)],
+      manufacturer: "Tesla",
+      name: name,
+      model: model
+    }
     |> maybe_put(:configuration_url, base_url)
   end
 
+  defp device_identifier(car_id, namespace) do
+    [@node, namespace, "car", car_id] |> Enum.reject(&is_nil/1) |> Enum.join("_")
+  end
+
   defp car_name(%Summary{car: %Car{name: name}}) when is_binary(name) and name != "", do: name
   defp car_name(_), do: nil
 

test/teslamate/mqtt/pubsub/home_assistant_test.exs

@@ -97,6 +97,28 @@ defmodule TeslaMate.Mqtt.PubSub.HomeAssistantTest do
     assert String.starts_with?(topic, "custom_prefix/")
   end
 
+  test "scopes node, unique_id and device by namespace", %{test: name} do
+    publisher_name = start_publisher(name)
+
+    :ok =
+      HomeAssistant.publish(
+        @summary,
+        [car_id: 0, namespace: "ns1"],
+        {MqttPublisherMock, publisher_name}
+      )
+
+    find_config("homeassistant/sensor/teslamate_ns1_0/speed/config", fn decoded ->
+      assert decoded["object_id"] == "tesla_speed"
+      assert decoded["unique_id"] == "teslamate_ns1_0_speed"
+      assert decoded["state_topic"] == "teslamate/ns1/cars/0/speed"
+      assert decoded["device"]["identifiers"] == ["teslamate_ns1_car_0"]
+    end)
+
+    find_config("homeassistant/sensor/teslamate_ns1_0/display_name/config", fn decoded ->
+      assert decoded["unique_id"] == "teslamate_ns1_0_display_name"
+    end)
+  end
+
   test "locked binary sensor is inverted", %{test: name} do
     publisher_name = start_publisher(name)
 

website/docs/integrations/home_assistant.md

@@ -36,10 +36,13 @@ Enable it with the following environment variables (see [Environment variables](
 | `MQTT_HOME_ASSISTANT_DISCOVERY_PREFIX` | Discovery topic prefix. Must match Home Assistant's `discovery_prefix` setting.                | `homeassistant` |
 
 When enabled, TeslaMate publishes a retained `config` payload per entity to
-`<discovery_prefix>/<component>/<node>_<car_id>/<object_id>/config` on the first
-vehicle summary, where `<node>` is `teslamate`. The device is grouped under the
-`teslamate_car_<car_id>` identifier, and the entity IDs match those produced by
-the manual `mqtt_sensors.yaml` below.
+`<discovery_prefix>/<component>/<node>/<object_id>/config` on the first
+vehicle summary, where `<node>` is `teslamate_<car_id>`. If
+`MQTT_NAMESPACE` is set, it is inserted after `teslamate_` (e.g.
+`teslamate_<namespace>_<car_id>`), so multiple TeslaMate instances sharing a
+broker do not collide on the same discovery topics. The device is grouped
+under the `teslamate_car_<car_id>` identifier (likewise namespace-scoped), and
+the entity IDs match those produced by the manual `mqtt_sensors.yaml` below.
 
 :::note