M8-R01: add configurable MQTT client identity

tests/test_api_config.py

@@ -454,6 +454,7 @@ def test_get_config_includes_mqtt_section(client: TestClient) -> None:
     assert "MQTT_USERNAME" in env_names
     assert "MQTT_PASSWORD" in env_names
     assert "MQTT_TLS_ENABLED" in env_names
+    assert "MQTT_CLIENT_ID" in env_names
 
 
 def test_get_config_includes_ha_discovery_section(client: TestClient) -> None:
@@ -578,6 +579,18 @@ def test_put_config_invalid_mqtt_port_returns_422_and_does_not_write(
     assert rows.get("MQTT_BROKER_PORT") != "not-a-number"
 
 
+def test_put_config_invalid_mqtt_client_id_returns_422(client: TestClient) -> None:
+    _login(client)
+
+    response = client.put(
+        "/api/config",
+        json={"updates": _full_config_payload({"MQTT_CLIENT_ID": "invalid id"})},
+        headers={"X-CSRF-Token": "token"},
+    )
+
+    assert response.status_code == 422
+
+
 # ---------------------------------------------------------------------------
 # M5-polish2 Area B: bool fields have input_type="checkbox"
 # ---------------------------------------------------------------------------
@@ -722,6 +735,32 @@ def test_put_config_mqtt_reconnect_uses_db_merged_settings(
     )
 
 
+def test_put_config_mqtt_client_id_reconnects_and_trims_value(
+    client: TestClient, test_database_urls
+) -> None:
+    _login(client)
+    mock_mgr = MagicMock()
+
+    with patch("app.api.routes.api.config.mqtt_manager", mock_mgr):
+        response = client.put(
+            "/api/config",
+            json={"updates": _full_config_payload({"MQTT_CLIENT_ID": " home-automation-dev "})},
+            headers={"X-CSRF-Token": "token"},
+        )
+
+    assert response.status_code == 200
+    reconnect_settings = mock_mgr.reconnect.call_args.args[0]
+    assert reconnect_settings.mqtt_client_id == "home-automation-dev"
+    conn = sqlite3.connect(test_database_urls["app_path"])
+    try:
+        stored_value = conn.execute(
+            "SELECT value FROM app_config WHERE key = 'MQTT_CLIENT_ID'"
+        ).fetchone()
+    finally:
+        conn.close()
+    assert stored_value == ("home-automation-dev",)
+
+
 # ---------------------------------------------------------------------------
 # M6-T02: DSMR + Tibber CONFIG_FIELDS
 # ---------------------------------------------------------------------------

tests/test_app.py

@@ -112,6 +112,7 @@ def test_app_start_seeds_missing_config_from_env_without_overwriting_existing_va
     assert rows["APP_NAME"] == "Database Owned Name"
     assert rows["HOME_ASSISTANT_BASE_URL"] == "http://bootstrap-ha.local:8123"
     assert rows["AUTH_SESSION_COOKIE_NAME"] == "home_automation_session"
+    assert rows["MQTT_CLIENT_ID"] == "home-automation"
 
     get_settings.cache_clear()
     reset_db_caches()

tests/test_dsmr_subscription_apply.py

@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 from dataclasses import replace
+from types import SimpleNamespace
 
 import pytest
 
@@ -44,6 +45,7 @@ def fake_mqtt(monkeypatch):
     fake = _FakeMqtt()
     monkeypatch.setattr("app.integrations.mqtt.mqtt_manager", fake)
     monkeypatch.setattr(dsmr_ingest, "_subscriptions", {})
+    monkeypatch.setattr(dsmr_ingest, "_subscription_client_ids", {})
     monkeypatch.setattr(dsmr_ingest, "_tariffs", {})
     return fake
 
@@ -81,6 +83,18 @@ def test_same_snapshot_has_no_subscription_churn(fake_mqtt, monkeypatch):
     assert fake_mqtt.remove_calls == []
 
 
+def test_changed_base_client_id_replaces_all_enabled_sources(fake_mqtt, monkeypatch):
+    snapshot = _source(1, "topic", broker_host="broker.test")
+    monkeypatch.setattr(dsmr_ingest, "_enabled_snapshots", lambda: [snapshot])
+
+    dsmr_ingest.apply_dsmr_subscription(SimpleNamespace(mqtt_client_id="home-automation"))
+    dsmr_ingest.apply_dsmr_subscription(SimpleNamespace(mqtt_client_id="home-automation-dev"))
+
+    assert fake_mqtt.remove_calls == [1]
+    assert [source_id for source_id, _ in fake_mqtt.replace_calls] == [1, 1]
+    assert fake_mqtt.replace_calls[-1][1]["base_client_id"] == "home-automation-dev"
+
+
 def test_same_topic_on_different_brokers_is_allowed(fake_mqtt, monkeypatch):
     monkeypatch.setattr(
         dsmr_ingest,

tests/test_mqtt_client.py

@@ -9,7 +9,7 @@ from unittest.mock import MagicMock, patch
 import pytest
 from fastapi.testclient import TestClient
 
-from app.integrations.mqtt import MqttManager
+from app.integrations.mqtt import MqttManager, mqtt_source_client_id, mqtt_test_client_id
 
 
 # ---------------------------------------------------------------------------
@@ -24,6 +24,7 @@ def _make_settings(
     mqtt_username: str = "",
     mqtt_password: str = "",
     mqtt_tls_enabled: bool = False,
+    mqtt_client_id: str = "home-automation",
     ha_discovery_prefix: str = "homeassistant",
 ):
     """Return a simple namespace that acts like a Settings object for MqttManager tests."""
@@ -34,6 +35,7 @@ def _make_settings(
     s.mqtt_username = mqtt_username
     s.mqtt_password = mqtt_password
     s.mqtt_tls_enabled = mqtt_tls_enabled
+    s.mqtt_client_id = mqtt_client_id
     s.ha_discovery_prefix = ha_discovery_prefix
     return s
 
@@ -120,6 +122,34 @@ def test_connect_creates_paho_client_with_version2() -> None:
     )
 
 
+def test_connect_uses_configured_client_id() -> None:
+    manager = MqttManager()
+    settings = _make_settings(mqtt_client_id="home-automation-dev")
+    mock_client = MagicMock()
+
+    with patch("app.integrations.mqtt.mqtt.Client", return_value=mock_client) as mock_cls:
+        manager.connect(settings)
+
+    assert mock_cls.call_args.kwargs["client_id"] == "home-automation-dev"
+
+
+def test_deployment_client_id_variants_are_distinct() -> None:
+    production_ids = {
+        "home-automation",
+        mqtt_source_client_id("home-automation", 7),
+        mqtt_test_client_id("home-automation"),
+    }
+    development_ids = {
+        "home-automation-dev",
+        mqtt_source_client_id("home-automation-dev", 7),
+        mqtt_test_client_id("home-automation-dev"),
+    }
+
+    assert len(production_ids) == 3
+    assert len(development_ids) == 3
+    assert production_ids.isdisjoint(development_ids)
+
+
 def test_connect_sets_credentials_when_username_provided() -> None:
     manager = MqttManager()
     settings = _make_settings(mqtt_username="user", mqtt_password="s3cr3t")
@@ -431,3 +461,17 @@ def test_run_mqtt_test_raises_connection_error_on_timeout() -> None:
         with patch("threading.Event", side_effect=_make_event):
             with pytest.raises(_MqttConnectionError, match="timed out"):
                 _run_mqtt_test(settings)
+
+
+def test_run_mqtt_test_uses_deployment_scoped_client_id() -> None:
+    from app.api.routes.api.config import _run_mqtt_test, _MqttConnectionError
+
+    settings = _make_settings(mqtt_client_id="home-automation-dev")
+    mock_client = MagicMock()
+    mock_client.connect.side_effect = OSError("Connection refused")
+
+    with patch("paho.mqtt.client.Client", return_value=mock_client) as mock_cls:
+        with pytest.raises(_MqttConnectionError):
+            _run_mqtt_test(settings)
+
+    assert mock_cls.call_args.kwargs["client_id"] == "home-automation-dev-test"

tests/test_mqtt_subscribe.py

@@ -251,6 +251,7 @@ def test_replace_source_uses_isolated_client_and_source_credentials() -> None:
             password="one-secret",
             tls_enabled=True,
             subscriptions={"one/topic": lambda payload: received.append(("one", payload))},
+            base_client_id="home-automation-dev",
         )
         manager.replace_source(
             2,
@@ -284,6 +285,25 @@ def test_replace_source_uses_isolated_client_and_source_credentials() -> None:
     assert received == [("two", b"two"), ("changed", b"changed")]
 
 
+def test_source_client_id_is_scoped_by_deployment_and_source() -> None:
+    manager = MqttManager()
+    client = MagicMock()
+
+    with patch("app.integrations.mqtt.mqtt.Client", return_value=client) as mock_cls:
+        assert manager.replace_source(
+            42,
+            host="broker.test",
+            port=1883,
+            username="",
+            password="",
+            tls_enabled=False,
+            subscriptions={"topic": lambda _payload: None},
+            base_client_id="home-automation-dev",
+        )
+
+    assert mock_cls.call_args.kwargs["client_id"] == "home-automation-dev-dsmr-source-42"
+
+
 def test_replaced_source_client_callbacks_cannot_reach_new_generation() -> None:
     """A retained old paho client cannot subscribe, mutate state, or dispatch new handlers."""
     manager = MqttManager()