overleaf/libraries/metrics
..
test
.dockerignore
.gitignore
.npmignore
.nvmrc
buildscript.txt
CHANGELOG.md
event_loop.js
http.js
index.js
initialize.js
leaked_sockets.js
LICENSE
memory.js
mongodb.js
open_sockets.js
package.json
prom_wrapper.js
README.md
timeAsyncMethod.js
uv_threadpool_size.js

overleaf/metrics-module

Wrappers the prom-client npm module to provide Prometheus metrics at /metrics.

Use:

// Metrics must be initialized before importing anything else
require('@overleaf/metrics/initialize')

const express = require('express')
const metrics = require('@overleaf/metrics')
const app = express()
metrics.injectMetricsRoute(app)

Request logging can be enabled:

const logger = require('@overleaf/logger')
...
app.use(metrics.http.monitor(logger))

The metrics module can be configured through the following environment variables:

  • DEBUG_METRICS - enables display of debugging messages to the console.
  • GCP_OPENTELEMETRY - enables OpenTelemetry tracing for GCP
  • JAEGER_OPENTELEMETRY - enables OpenTelemetry tracing for Jaeger (in the dev environment)
  • METRICS_APP_NAME - the app label for metrics and spans
  • METRICS_COMPRESSION_LEVEL - sets the compression level for /metrics
  • STACKDRIVER_LOGGING - toggles the request logging format
  • UV_THREADPOOL_SIZE - sets the libuv thread pool size