stackdriverlogger.ts

stackdriverpino.ts

import * as P from 'pino'
import {FastifyReply, FastifyRequest} from 'fastify'

const enum PINO_LEVELS {
  trace = 10,
  debug = 20,
  info = 30,
  warn = 40,
  error = 50,
  fatal = 60,
}

const enum StackdriverSeverity {
  default = 'DEFAULT',
  debug = 'DEBUG',
  info = 'INFO',
  notice = 'NOTICE',
  warning = 'WARNING',
  error = 'ERROR',
  critical = 'CRITICAL',
  alert = 'ALERT',
  emergency = 'EMERGENCY'
}

function pinoLevelToStackdriverSeverity(level: PINO_LEVELS): StackdriverSeverity {
  switch (level) {
    case PINO_LEVELS.trace:
    case PINO_LEVELS.debug:
      return StackdriverSeverity.debug
    case PINO_LEVELS.info:
      return StackdriverSeverity.info
    case PINO_LEVELS.warn:
      return StackdriverSeverity.warning
    case PINO_LEVELS.error:
      return StackdriverSeverity.error
    case PINO_LEVELS.fatal:
      return StackdriverSeverity.critical
    default:
      return StackdriverSeverity.default
  }
}

function truncateToDecimalPlace(value: number, decimalPlace: number) {
  return (
    Math.trunc(value * Math.pow(10, decimalPlace)) / Math.pow(10, decimalPlace)
  )
}

interface LogEntryHTTPRequest {
  requestMethod?: string
  requestUrl?: string
  requestSize?: string
  status?: number
  responseSize?: string
  userAgent?: string
  remoteIp?: string
  serverIp?: string
  referer?: string
  latency?: string
  cacheLookup?: boolean
  cacheHit?: boolean
  cacheValidatedWithOriginServer?: boolean
  cacheFillBytes?: string
  protocol?: string
}

interface LogObject {
  req?: FastifyRequest
  res?: FastifyReply
  httpRequest?: LogEntryHTTPRequest
  requestId?: string
}

export default function logger(level: P.Level): P.Logger {
  return P({
    messageKey: 'message',
    timestamp: false,
    base: undefined,
    level: level,

    formatters: {
      level(_label, number) {
        return {
          severity: pinoLevelToStackdriverSeverity(number),
        }
      },
      log(object: LogObject) {
        // Setuping the Stackdriver httpRequest property on the log entry
        if (object.req) {
          object.httpRequest = {
            ...(object.httpRequest ?? {},
            {
              requestMethod: object.req.method,
              requestUrl: object.req.url,
              userAgent: object.req.headers['user-agent'],
              remoteIp: object.req.ips?.[0] ?? object.req.ip,
              protocol: object.req.protocol,
            })
          }
        }
        if (object.res) {
          object.httpRequest = {
            ...(object.httpRequest ?? {},
            {
              requestMethod: object.res.request.method,
              requestUrl: object.res.request.url,
              status: object.res.statusCode,
              userAgent: object.res.request.headers['user-agent'],
              latency: `${truncateToDecimalPlace(object.res.getResponseTime() / 1000, 9)}s`,
              remoteIp: object.res.request.ips?.[0] ?? object.res.request.ip,
              protocol: object.res.request.protocol,
            }),
          }
        }
        return object
      }
    },
    serializers: {
      // Nullifying the standard Fastify Request/Response serializer for better stackdriver support
      req(request: FastifyRequest) { return undefined },
      res(reply: FastifyReply) { return undefined },
      responseTime: function(value) { return undefined }
    }
  })
}