From acef9e7d8d7f71cbff6912e210c4165acfc3eaa7 Mon Sep 17 00:00:00 2001
From: Christopher Hoskin <christopher.hoskin@gmail.com>
Date: Tue, 16 Mar 2021 11:47:18 +0000
Subject: [PATCH] Add basic README

---
 libraries/metrics/README.md | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 libraries/metrics/README.md

diff --git a/libraries/metrics/README.md b/libraries/metrics/README.md
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+++ b/libraries/metrics/README.md
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+overleaf/metrics-module
+=======================
+
+Wrappers the [prom-client](https://github.com/siimon/prom-client) npm module to provide [Prometheus](https://prometheus.io/) 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('logger-sharelatex')
+...
+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](https://www.npmjs.com/package/compression#level) for `/metrics`
+* `STACKDRIVER_LOGGING` - toggles the request logging format
+* `UV_THREADPOOL_SIZE` - sets the libuv [thread pool](http://docs.libuv.org/en/v1.x/threadpool.html) size
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