Cloudflare purge errors are not being displayed in Slack correctly

[msheiny]

Example trigger document

{
  "_index": "syslog-logstash-2018.10.25",
  "_type": "log",
  "_id": "AWasEmi4kghPo1MVs-4i",
  "_score": 1,
  "_source": {
    "offset": 907205,
    "module": "backends",
    "input_type": "log",
    "source": "/var/www/django-alpha/logs/django-other.log",
    "message": "Couldn't purge 'https://pressfreedomtracker.us/' from Cloudflare. Cloudflare errors 'Unable to purge https://pressfreedomtracker.us/, One or more cache purge errors'",
    "type": "log",
    "tags": [
      "djangofpf",
      "beats_input_codec_plain_applied"
    ],
    "@timestamp": "2018-10-25T16:32:56.430Z",
    "loglevel": "ERROR",
    "@version": "1",
    "beat": {
      "name": "www-tracker",
      "hostname": "www-tracker",
      "version": "5.6.8"
    },
    "host": "www-tracker",
    "name": "wagtail.frontendcache"
  },
  "fields": {
    "@timestamp": [
      1540485176430
    ]
  }
}

Corresponding slack event

Here's a picture of Jeff Goldblum:

[conorsch]

Old issue, we've retooled the alerting quite a bit since this was relevant.