overleaf/libraries/metrics/README.md

overleaf/metrics-module

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

Use:

const metrics = require('@overleaf/metrics')
metrics.initialize('myapp')

const express = require('express')
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.
• ENABLE_TRACE_AGENT - enables @google-cloud/trace-agent on Google Cloud
• ENABLE_DEBUG_AGENT - enables @google-cloud/debug-agent on Google Cloud
• ENABLE_PROFILE_AGENT - enables @google-cloud/profiler on Google Cloud
• 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