server/lib/opentelemetry/metrics.ts

   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'
   5 import { logger } from '@server/helpers/logger'
   6 import { CONFIG } from '@server/initializers/config'
   7 import { MVideoImmutable } from '@server/types/models'
   8 import { PlaybackMetricCreate } from '@shared/models'
   9 import {
  10   JobQueueObserversBuilder,
  11   LivesObserversBuilder,
  12   NodeJSObserversBuilder,
  13   PlaybackMetrics,
  14   StatsObserversBuilder,
  15   ViewersObserversBuilder
  16 } from './metric-helpers'
  17
  18 class OpenTelemetryMetrics {
  19
  20   private static instance: OpenTelemetryMetrics
  21
  22   private meter: Meter
  23
  24   private onRequestDuration: (req: Request, res: Response) => void
  25
  26   private playbackMetrics: PlaybackMetrics
  27
  28   private constructor () {}
  29
  30   init (app: Application) {
  31     if (CONFIG.OPEN_TELEMETRY.METRICS.ENABLED !== true) return
  32
  33     app.use((req, res, next) => {
  34       res.once('finish', () => {
  35         if (!this.onRequestDuration) return
  36
  37         this.onRequestDuration(req as Request, res as Response)
  38       })
  39
  40       next()
  41     })
  42   }
  43
  44   registerMetrics () {
  45     if (CONFIG.OPEN_TELEMETRY.METRICS.ENABLED !== true) return
  46
  47     logger.info('Registering Open Telemetry metrics')
  48
  49     const provider = new MeterProvider({
  50       views: [
  51         ...NodeJSObserversBuilder.getViews()
  52       ]
  53     })
  54
  55     provider.addMetricReader(new PrometheusExporter({ port: CONFIG.OPEN_TELEMETRY.METRICS.PROMETHEUS_EXPORTER.PORT }))
  56
  57     metrics.setGlobalMeterProvider(provider)
  58
  59     this.meter = metrics.getMeter('default')
  60
  61     this.buildRequestObserver()
  62
  63     this.playbackMetrics = new PlaybackMetrics(this.meter)
  64     this.playbackMetrics.buildCounters()
  65
  66     const nodeJSObserversBuilder = new NodeJSObserversBuilder(this.meter)
  67     nodeJSObserversBuilder.buildObservers()
  68
  69     const jobQueueObserversBuilder = new JobQueueObserversBuilder(this.meter)
  70     jobQueueObserversBuilder.buildObservers()
  71
  72     const statsObserversBuilder = new StatsObserversBuilder(this.meter)
  73     statsObserversBuilder.buildObservers()
  74
  75     const livesObserversBuilder = new LivesObserversBuilder(this.meter)
  76     livesObserversBuilder.buildObservers()
  77
  78     const viewersObserversBuilder = new ViewersObserversBuilder(this.meter)
  79     viewersObserversBuilder.buildObservers()
  80   }
  81
  82   observePlaybackMetric (video: MVideoImmutable, metrics: PlaybackMetricCreate) {
  83     this.playbackMetrics.observe(video, metrics)
  84   }
  85
  86   private buildRequestObserver () {
  87     const requestDuration = this.meter.createHistogram('http_request_duration_ms', {
  88       unit: 'milliseconds',
  89       description: 'Duration of HTTP requests in ms'
  90     })
  91
  92     this.onRequestDuration = (req: Request, res: Response) => {
  93       const duration = Date.now() - res.locals.requestStart
  94
  95       requestDuration.record(duration, {
  96         path: this.buildRequestPath(req.originalUrl),
  97         method: req.method,
  98         statusCode: res.statusCode + ''
  99       })
 100     }
 101   }
 102
 103   private buildRequestPath (path: string) {
 104     return path.split('?')[0]
 105   }
 106
 107   static get Instance () {
 108     return this.instance || (this.instance = new this())
 109   }
 110 }
 111
 112 export {
 113   OpenTelemetryMetrics
 114 }