Mock Elastic APM Server that always responds with an error before bothering to read the entire request body

server.js

'use strict'

const zlib = require('zlib')
const http = require('http')

const body = zlib.gzipSync(JSON.stringify({
  errors: {
    ERR_QUEUE_FULL: {
      count: 23,
      message: 'queue is full'
    },
    ERR_PROCESSING_TIMEOUT: {
      count: 2,
      message: 'timeout while waiting to process'
    },
    ERR_SCHEMA_VALIDATION: {
      count: 3,
      message: 'could not validate object',
      documents: [
        {error: '<json-schema-err>', document: '<ndjson-obj>'}
      ]
    },
    ERR_INVALID_JSON: {
      count: 24,
      message: 'could not decode JSON',
      documents: [
        {error: '<json-decoding-err>', document: '<ndjson-obj>'}
      ]
    },
    ERR_INVALID_CONTENT_TYPE: {
      message: 'invalid content-type: \'html/text\''
    },
    ERR_SERVER_ERROR: {
      message: 'i/o timeout while reading..'
    }
  },
  accepted: 2320,
  dropped: 25,
  invalid: 3
}))

const server = http.createServer(function (req, res) {
  console.log(req.method, req.url)
  res.writeHead(500, {
    'Content-Encoding': 'gzip',
    'Content-Length': body.length,
    'Content-Type': 'application/json'
  })
  res.end(body)
})

server.listen(8200, function () {
  console.log('Server running on http://localhost:8200')
})