feat(prometheus): add metrics

package.json

@@ -50,6 +50,7 @@
     "@nestjs/schedule": "^0.4.1",
     "@nestjs/swagger": "^4.7.9",
     "@nestjs/terminus": "^7.0.1",
+    "@willsoto/nestjs-prometheus": "^3.0.0",
     "async-mqtt": "^2.6.1",
     "chalk": "^4.1.0",
     "class-transformer": "^0.3.1",
@@ -65,6 +66,7 @@
     "mathjs": "^8.1.1",
     "nest-emitter": "^1.1.1",
     "nest-winston": "^1.4.0",
+    "prom-client": "^13.0.0",
     "pureimage": "^0.2.5",
     "reflect-metadata": "^0.1.13",
     "rxjs": "^6.6.3",

src/app.module.ts

@@ -10,6 +10,7 @@ import { NestEmitterModule } from 'nest-emitter';
 import { EventEmitter } from 'events';
 import { WINSTON_LOGGER } from './logger';
 import { StatusModule } from './status/status.module';
+import { PrometheusModule } from '@willsoto/nestjs-prometheus';
 
 // eslint-disable-next-line @typescript-eslint/no-var-requires
 export const VERSION = require('../package.json').version;
@@ -26,6 +27,7 @@ export const CONFIGURED_INTEGRATIONS = c
     StatusModule,
     ScheduleModule.forRoot(),
     NestEmitterModule.forRoot(new EventEmitter()),
+    PrometheusModule.register(),
     IntegrationsModule.register(CONFIGURED_INTEGRATIONS, WINSTON_LOGGER),
   ],
 })

src/integrations/bluetooth/bluetooth.module.ts

@@ -4,10 +4,19 @@ import { BluetoothHealthIndicator } from './bluetooth.health';
 import { ConfigModule } from '../../config/config.module';
 import { StatusModule } from '../../status/status.module';
 import { ScheduleModule } from '@nestjs/schedule';
+import { makeCounterProvider } from '@willsoto/nestjs-prometheus';
 
 @Module({
   imports: [ConfigModule, StatusModule, ScheduleModule.forRoot()],
-  providers: [BluetoothService, BluetoothHealthIndicator],
+  providers: [
+    BluetoothService,
+    BluetoothHealthIndicator,
+    makeCounterProvider({
+      name: 'bluetooth_le_advertisements_received_count',
+      help:
+        'Number of Bluetooth Low Energy advertisements that were detected by this device',
+    }),
+  ],
   exports: [BluetoothService],
 })
 export class BluetoothModule {}

src/integrations/bluetooth/bluetooth.service.spec.ts

@@ -1,3 +1,5 @@
+import { makeCounterProvider } from '@willsoto/nestjs-prometheus';
+
 const mockExec = jest.fn();
 const mockNoble = {
   state: 'poweredOn',
@@ -40,7 +42,14 @@ describe('BluetoothService', () => {
 
     const module: TestingModule = await Test.createTestingModule({
       imports: [ConfigModule],
-      providers: [BluetoothService, BluetoothHealthIndicator],
+      providers: [
+        BluetoothService,
+        BluetoothHealthIndicator,
+        makeCounterProvider({
+          name: 'bluetooth_le_advertisements_received_count',
+          help: '',
+        }),
+      ],
     })
       .overrideProvider(BluetoothHealthIndicator)
       .useValue(healthIndicator)

src/integrations/bluetooth/bluetooth.service.ts

@@ -9,6 +9,8 @@ import { Device } from '../bluetooth-classic/device';
 import { promiseWithTimeout, sleep } from '../../util/promises';
 import { Interval } from '@nestjs/schedule';
 import _ from 'lodash';
+import { Counter } from 'prom-client';
+import { InjectMetric } from '@willsoto/nestjs-prometheus';
 
 const RSSI_REGEX = new RegExp(/-?[0-9]+/);
 const INQUIRY_LOCK_TIMEOUT = 30 * 1000;
@@ -44,7 +46,9 @@ export class BluetoothService {
 
   constructor(
     private readonly configService: ConfigService,
-    private readonly healthIndicator: BluetoothHealthIndicator
+    private readonly healthIndicator: BluetoothHealthIndicator,
+    @InjectMetric('bluetooth_le_advertisements_received_count')
+    private readonly advertisementReceivedCounter: Counter<string>
   ) {
     this.classicConfig = this.configService.get('bluetoothClassic');
   }
@@ -393,6 +397,7 @@ export class BluetoothService {
     noble.on('stateChange', this.handleAdapterStateChange.bind(this));
     noble.on('discover', () => {
       this.lastLowEnergyDiscovery = new Date();
+      this.advertisementReceivedCounter.inc();
       if (this.adapters.getState(this.lowEnergyAdapterId) === 'inactive') {
         this.adapters.setState(this.lowEnergyAdapterId, 'scan');
       }