feat(home-assistant): add health indicator

src/integrations/home-assistant/home-assistant.health.spec.ts

@@ -0,0 +1,31 @@
+import { HomeAssistantHealthIndicator } from './home-assistant.health';
+import { HomeAssistantService } from './home-assistant.service';
+import { HealthCheckError } from '@nestjs/terminus';
+
+describe('HomeAssistantHealthIndicator', () => {
+  const serviceMock = {
+    isConnected: jest.fn(),
+  };
+  const healthIndicator = new HomeAssistantHealthIndicator(
+    (serviceMock as unknown) as HomeAssistantService
+  );
+
+  it('should report healthy if connection is established', () => {
+    serviceMock.isConnected.mockReturnValue(true);
+
+    const result = healthIndicator.connectionCheck();
+    expect(result['ha_mqtt_connected'].status).toEqual('up');
+  });
+
+  it('should report unhealthy if connection not established yet', () => {
+    serviceMock.isConnected.mockReturnValue(undefined);
+
+    expect(() => healthIndicator.connectionCheck()).toThrow(HealthCheckError);
+  });
+
+  it('should report unhealthy if connection lost', () => {
+    serviceMock.isConnected.mockReturnValue(false);
+
+    expect(() => healthIndicator.connectionCheck()).toThrow(HealthCheckError);
+  });
+});

src/integrations/home-assistant/home-assistant.health.ts

@@ -0,0 +1,32 @@
+import {
+  HealthCheckError,
+  HealthIndicator,
+  HealthIndicatorResult,
+} from '@nestjs/terminus';
+import { Injectable, Optional } from '@nestjs/common';
+import { HealthIndicatorService } from '../../status/health-indicator.service';
+import { HomeAssistantService } from './home-assistant.service';
+
+@Injectable()
+export class HomeAssistantHealthIndicator extends HealthIndicator {
+  constructor(
+    private readonly homeAssistantService: HomeAssistantService,
+    @Optional() healthIndicatorService?: HealthIndicatorService
+  ) {
+    super();
+    healthIndicatorService?.registerHealthIndicator(async () =>
+      this.connectionCheck()
+    );
+  }
+
+  connectionCheck(): HealthIndicatorResult {
+    const isHealthy = this.homeAssistantService.isConnected();
+    const result = this.getStatus('ha_mqtt_connected', isHealthy);
+
+    if (isHealthy) {
+      return result;
+    }
+
+    throw new HealthCheckError('No connection to MQTT broker', result);
+  }
+}

src/integrations/home-assistant/home-assistant.module.ts

@@ -2,14 +2,16 @@ import { DynamicModule, Module } from '@nestjs/common';
 import { HomeAssistantService } from './home-assistant.service';
 import { ConfigModule } from '../../config/config.module';
 import { EntitiesModule } from '../../entities/entities.module';
+import { StatusModule } from '../../status/status.module';
+import { HomeAssistantHealthIndicator } from './home-assistant.health';
 
 @Module({})
 export default class HomeAssistantModule {
   static forRoot(): DynamicModule {
     return {
       module: HomeAssistantModule,
-      imports: [ConfigModule, EntitiesModule],
-      providers: [HomeAssistantService],
+      imports: [ConfigModule, EntitiesModule, StatusModule],
+      providers: [HomeAssistantService, HomeAssistantHealthIndicator],
     };
   }
 }

src/integrations/home-assistant/home-assistant.service.ts

@@ -253,6 +253,13 @@ export class HomeAssistantService
     }
   }
 
+  /**
+   * Checks if room-assistant is connected to the MQTT broker.
+   */
+  isConnected(): boolean {
+    return this.mqttClient?.connected;
+  }
+
   /**
    * Handles broker re-connection events.
    */