overleaf/libraries/metrics/index.js

let Metrics
console.log('using prometheus')

const ExpressCompression = require('compression')
const prom = require('./prom_wrapper')

const { collectDefaultMetrics } = prom

let appname = 'unknown'
const hostname = require('os').hostname()

const destructors = []

require('./uv_threadpool_size')

module.exports = Metrics = {
  register: prom.registry,

  initialize(_name, opts = {}) {
    appname = _name
    collectDefaultMetrics({ timeout: 5000, prefix: Metrics.buildPromKey() })
    if (opts.ttlInMinutes) {
      prom.ttlInMinutes = opts.ttlInMinutes
    }

    console.log(`ENABLE_TRACE_AGENT set to ${process.env.ENABLE_TRACE_AGENT}`)
    if (process.env.ENABLE_TRACE_AGENT === 'true') {
      console.log('starting google trace agent')
      const traceAgent = require('@google-cloud/trace-agent')

      const traceOpts = { ignoreUrls: [/^\/status/, /^\/health_check/] }
      traceAgent.start(traceOpts)
    }

    console.log(`ENABLE_DEBUG_AGENT set to ${process.env.ENABLE_DEBUG_AGENT}`)
    if (process.env.ENABLE_DEBUG_AGENT === 'true') {
      console.log('starting google debug agent')
      const debugAgent = require('@google-cloud/debug-agent')
      debugAgent.start({
        allowExpressions: true,
        serviceContext: {
          service: appname,
          version: process.env.BUILD_VERSION
        }
      })
    }

    console.log(
      `ENABLE_PROFILE_AGENT set to ${process.env.ENABLE_PROFILE_AGENT}`
    )
    if (process.env.ENABLE_PROFILE_AGENT === 'true') {
      console.log('starting google profile agent')
      const profiler = require('@google-cloud/profiler')
      profiler.start({
        serviceContext: {
          service: appname,
          version: process.env.BUILD_VERSION
        }
      })
    }

    Metrics.inc('process_startup')
  },

  registerDestructor(func) {
    destructors.push(func)
  },

  injectMetricsRoute(app) {
    app.get(
      '/metrics',
      ExpressCompression({
        level: parseInt(process.env.METRICS_COMPRESSION_LEVEL || '1', 10)
      }),
      function(req, res) {
        res.set('Content-Type', prom.registry.contentType)
        res.end(prom.registry.metrics())
      }
    )
  },

  buildPromKey(key = '') {
    return key.replace(/[^a-zA-Z0-9]/g, '_')
  },

  sanitizeValue(value) {
    return parseFloat(value)
  },

  set(key, value, sampleRate = 1) {
    console.log('counts are not currently supported')
  },

  inc(key, sampleRate = 1, opts = {}) {
    key = Metrics.buildPromKey(key)
    opts.app = appname
    opts.host = hostname
    prom.metric('counter', key).inc(opts)
    if (process.env.DEBUG_METRICS) {
      console.log('doing inc', key, opts)
    }
  },

  count(key, count, sampleRate = 1, opts = {}) {
    key = Metrics.buildPromKey(key)
    opts.app = appname
    opts.host = hostname
    prom.metric('counter', key).inc(opts, count)
    if (process.env.DEBUG_METRICS) {
      console.log('doing count/inc', key, opts)
    }
  },

  summary(key, value, opts = {}) {
    key = Metrics.buildPromKey(key)
    opts.app = appname
    opts.host = hostname
    prom.metric('summary', key).observe(opts, value)
    if (process.env.DEBUG_METRICS) {
      console.log('doing summary', key, value, opts)
    }
  },

  timing(key, timeSpan, sampleRate, opts = {}) {
    key = Metrics.buildPromKey('timer_' + key)
    opts.app = appname
    opts.host = hostname
    prom.metric('summary', key).observe(opts, timeSpan)
    if (process.env.DEBUG_METRICS) {
      console.log('doing timing', key, opts)
    }
  },

  Timer: class {
    constructor(key, sampleRate = 1, opts = {}) {
      this.start = new Date()
      key = Metrics.buildPromKey(key)
      this.key = key
      this.sampleRate = sampleRate
      this.opts = opts
    }

    done() {
      const timeSpan = new Date() - this.start
      Metrics.timing(this.key, timeSpan, this.sampleRate, this.opts)
      return timeSpan
    }
  },

  gauge(key, value, sampleRate = 1, opts = {}) {
    key = Metrics.buildPromKey(key)
    prom.metric('gauge', key).set(
      {
        app: appname,
        host: hostname,
        status: opts.status
      },
      this.sanitizeValue(value)
    )
    if (process.env.DEBUG_METRICS) {
      console.log('doing gauge', key, opts)
    }
  },

  globalGauge(key, value, sampleRate = 1, opts = {}) {
    key = Metrics.buildPromKey(key)
    prom
      .metric('gauge', key)
      .set({ app: appname, status: opts.status }, this.sanitizeValue(value))
  },

  mongodb: require('./mongodb'),
  http: require('./http'),
  open_sockets: require('./open_sockets'),
  event_loop: require('./event_loop'),
  memory: require('./memory'),

  timeAsyncMethod: require('./timeAsyncMethod'),

  close() {
    for (const func of destructors) {
      func()
    }
  }
}