1 import { Application, Request, Response } from 'express'
2 import { Meter, metrics } from '@opentelemetry/api-metrics'
3 import { PrometheusExporter } from '@opentelemetry/exporter-prometheus'
4 import { MeterProvider } from '@opentelemetry/sdk-metrics-base'
5 import { logger } from '@server/helpers/logger'
6 import { CONFIG } from '@server/initializers/config'
8 JobQueueObserversBuilder,
10 NodeJSObserversBuilder,
11 StatsObserversBuilder,
12 ViewersObserversBuilder
13 } from './metric-helpers'
15 class OpenTelemetryMetrics {
17 private static instance: OpenTelemetryMetrics
21 private onRequestDuration: (req: Request, res: Response) => void
23 private constructor () {}
25 init (app: Application) {
26 if (CONFIG.OPEN_TELEMETRY.METRICS.ENABLED !== true) return
28 app.use((req, res, next) => {
29 res.once('finish', () => {
30 if (!this.onRequestDuration) return
32 this.onRequestDuration(req as Request, res as Response)
40 if (CONFIG.OPEN_TELEMETRY.METRICS.ENABLED !== true) return
42 logger.info('Registering Open Telemetry metrics')
44 const provider = new MeterProvider()
46 provider.addMetricReader(new PrometheusExporter({ port: CONFIG.OPEN_TELEMETRY.METRICS.PROMETHEUS_EXPORTER.PORT }))
48 metrics.setGlobalMeterProvider(provider)
50 this.meter = metrics.getMeter('default')
52 this.buildRequestObserver()
54 const nodeJSObserversBuilder = new NodeJSObserversBuilder(this.meter, provider)
55 nodeJSObserversBuilder.buildObservers()
57 const jobQueueObserversBuilder = new JobQueueObserversBuilder(this.meter)
58 jobQueueObserversBuilder.buildObservers()
60 const statsObserversBuilder = new StatsObserversBuilder(this.meter)
61 statsObserversBuilder.buildObservers()
63 const livesObserversBuilder = new LivesObserversBuilder(this.meter)
64 livesObserversBuilder.buildObservers()
66 const viewersObserversBuilder = new ViewersObserversBuilder(this.meter)
67 viewersObserversBuilder.buildObservers()
70 private buildRequestObserver () {
71 const requestDuration = this.meter.createHistogram('http_request_duration_ms', {
73 description: 'Duration of HTTP requests in ms'
76 this.onRequestDuration = (req: Request, res: Response) => {
77 const duration = Date.now() - res.locals.requestStart
79 requestDuration.record(duration, {
80 path: this.buildRequestPath(req.originalUrl),
82 statusCode: res.statusCode + ''
87 private buildRequestPath (path: string) {
88 return path.split('?')[0]
91 static get Instance () {
92 return this.instance || (this.instance = new this())