Add apm-server-proxy (WIP)

[sorenlouv]

This adds a service that replaces apm server for testing purposes. Any data sent to apm server will be written to file. This file can later be used to replay event duration test scenarios.

1. Generate normal docker-compose.json file

./scripts/compose.py start master --all --docker-compose-path - > apm-server-proxied.json

2. In apm-server-proxied.json overwrite apm-server with the following and replace apm-server with apm-server-proxy everywhere:

    "apm-server-proxy": {
      "build": {
        "context": "docker/apm-server-proxy",
        "dockerfile": "Dockerfile"
      },
      "volumes": [
        "./docker/apm-server-proxy/shared-volume:/usr/app/shared-volume"
      ],
      "command": "npm start",
      "ports": ["127.0.0.1:8200:8200"],
      "environment": [
        "ELASTIC_APM_SERVER_HOST=apm-server-proxy",
        "ELASTIC_APM_SERVER_PORT=8200"
      ],
      "healthcheck": {
        "interval": "10s",
        "retries": 36,
        "test": [
          "CMD",
          "curl",
          "--write-out",
          "'HTTP %{http_code}'",
          "--fail",
          "--silent",
          "--output",
          "/dev/null",
          "http://apm-server-proxy:8200/"
        ]
      }
    },

3. Build and run the image

docker-compose -f apm-server-proxied.json build && docker-compose -f apm-server-proxied.json up

[sorenlouv]

console.log statements should be removed during testing. This is only needed for debugging purposes during development

[sorenlouv]

Instead of listening on a single endpoint we can also listen for all endpoints:

app.post('*', ...)

and write that to file containing the endpoint.

[sorenlouv]

Note to self: axios is no longer neeeded

[sorenlouv]

An example of how events can be replayed from file:

async function init() {
  const content = await readFile('./shared-volume/events.json');
  const items = JSON.parse(content.toString());

  for await (let item of items) {
    try {
      await axios({
        method: 'post',
        url: `http://${APM_SERVER_HOST}:${APM_SERVER_PORT}/intake/v2/events`,
        headers: { 'content-type': 'application/x-ndjson' },
        data: item
      });
    } catch (e) {
      console.log(e.response.data);
    }
  }
}

[v1v]

I just pushed 953e691 to fix the lint defects which were detected in the CI:

[2019-07-30T04:52:08.239Z] Fix End of Files................................................................................Failed
[2019-07-30T04:52:08.239Z] hookid: end-of-file-fixer
[2019-07-30T04:52:08.239Z] 
[2019-07-30T04:52:08.239Z] Files were modified by this hook. Additional output:
[2019-07-30T04:52:08.239Z] 
[2019-07-30T04:52:08.239Z] Fixing docker/apm-server-proxy/Dockerfile

[sorenlouv]

Closing in favor of #567