Introduce experimental telemetry

1 files changed, 111 insertions, 0 deletions

diff --git a/server/lib/opentelemetry/metrics.ts b/server/lib/opentelemetry/metrics.ts
new file mode 100644
index 000000000..ca0aae8e7
--- /dev/null
+++ b/server/lib/opentelemetry/metrics.ts
@@ -0,0 +1,111 @@
+import { Application, Request, Response } from 'express'
+import { Meter, metrics } from '@opentelemetry/api-metrics'
+import { PrometheusExporter } from '@opentelemetry/exporter-prometheus'
+import { MeterProvider } from '@opentelemetry/sdk-metrics-base'
+import { logger } from '@server/helpers/logger'
+import { CONFIG } from '@server/initializers/config'
+import { JobQueue } from '../job-queue'
+import { StatsObserverBuilder } from './metric-helpers'
+
+class OpenTelemetryMetrics {
+
+  private static instance: OpenTelemetryMetrics
+
+  private meter: Meter
+
+  private onRequestDuration: (req: Request, res: Response) => void
+
+  private constructor () {}
+
+  init (app: Application) {
+    if (CONFIG.OPEN_TELEMETRY.METRICS.ENABLED !== true) return
+
+    app.use((req, res, next) => {
+      res.once('finish', () => {
+        if (!this.onRequestDuration) return
+
+        this.onRequestDuration(req as Request, res as Response)
+      })
+
+      next()
+    })
+  }
+
+  registerMetrics () {
+    if (CONFIG.OPEN_TELEMETRY.METRICS.ENABLED !== true) return
+
+    logger.info('Registering Open Telemetry metrics')
+
+    const provider = new MeterProvider()
+
+    provider.addMetricReader(new PrometheusExporter({ port: CONFIG.OPEN_TELEMETRY.METRICS.PROMETHEUS_EXPORTER.PORT }))
+
+    metrics.setGlobalMeterProvider(provider)
+
+    this.meter = metrics.getMeter('default')
+
+    this.buildMemoryObserver()
+    this.buildRequestObserver()
+    this.buildJobQueueObserver()
+
+    const statsObserverBuilder = new StatsObserverBuilder(this.meter)
+    statsObserverBuilder.buildObservers()
+  }
+
+  private buildMemoryObserver () {
+    this.meter.createObservableGauge('nodejs_memory_usage_bytes', {
+      description: 'Memory'
+    }).addCallback(observableResult => {
+      const current = process.memoryUsage()
+
+      observableResult.observe(current.heapTotal, { memoryType: 'heapTotal' })
+      observableResult.observe(current.heapUsed, { memoryType: 'heapUsed' })
+      observableResult.observe(current.arrayBuffers, { memoryType: 'arrayBuffers' })
+      observableResult.observe(current.external, { memoryType: 'external' })
+      observableResult.observe(current.rss, { memoryType: 'rss' })
+    })
+  }
+
+  private buildJobQueueObserver () {
+    this.meter.createObservableGauge('peertube_job_queue_total', {
+      description: 'Total jobs in the PeerTube job queue'
+    }).addCallback(async observableResult => {
+      const stats = await JobQueue.Instance.getStats()
+
+      for (const { jobType, counts } of stats) {
+        for (const state of Object.keys(counts)) {
+          observableResult.observe(counts[state], { jobType, state })
+        }
+      }
+    })
+  }
+
+  private buildRequestObserver () {
+    const requestDuration = this.meter.createHistogram('http_request_duration_ms', {
+      unit: 'milliseconds',
+      description: 'Duration of HTTP requests in ms'
+    })
+
+    this.onRequestDuration = (req: Request, res: Response) => {
+      const duration = Date.now() - res.locals.requestStart
+
+      requestDuration.record(duration, {
+        path: this.buildRequestPath(req.originalUrl),
+        method: req.method,
+        statusCode: res.statusCode + ''
+      })
+    }
+  }
+
+  private buildRequestPath (path: string) {
+    return path.split('?')[0]
+  }
+
+  static get Instance () {
+    return this.instance || (this.instance = new this())
+  }
+}
+
+export {
+  OpenTelemetryMetrics
+}