Cloud Status Alerter

This repository contains a Ruby script that consumes the various service/vender status feeds and posts corresponding alerts to a specified Slack channel as events occur. A Google Cloud Firestore database is used to track a little state to ensure duplicate updates aren't posted.

Organisation

This repository contains the following sub-directories:

• app - Ruby command-line application that runs as a Kubernetes CronJob

• parent-image - Docker parent image containing Ruby and the dependencies required by the application. Used to speed up the Docker build

Building the Applications

Dockerfiles are included for building both the parent image and application.

Environment Variables

The environment variables below are required:

FIRESTORE_PROJECT           # Name of the GCP project containing the Firestore project
MONITORING_PROJECT          # Name of the GCP project containing the Cloud Pub/Sub topic to post alerts to
SLACK_PUBSUB_TOPIC          # Name of the Cloud Pub/Sub topic to post alerts to
STATUS_ALERTS_SLACK_CHANNEL # Name of the Slack channel to post alerts to

The environment variable below is optional:

FIRESTORE_CREDENTIALS       # Path to the GCP service account JSON key (used when running locally)

Providers

Updates from a status feed source are implemented by providers, which are simply classes within the providers directory that conform to these rules:

• Provider classes must inherit from the Provider base class
• Provider class names must have an initial capital and then be all lower-case e.g. Github
• The provider class's initialize method must set the @icon and @name for use within the Slack message (the icon should be the name of a Slack emoji minus the surrounding colons)
• The provider class must implement a latest_update method that returns a populated StatusFeedUpdate struct. This struct contains the following fields:

Field	Purpose
id	Unique ID for the update. Not displayed, used as a document key in Firestore
timestamp	Timestamp of the update
metadata	Optional additional information about the update e.g. the name of the service affected
text	Status update text
uri	URI for viewing this individual status update online

Copyright

Copyright (C) 2019–2022 Crown Copyright (Office for National Statistics)