A bot to receive Prometheus Alertmanager webhook events and forward them to chosen rooms.

Main features:

• Uses pre-created Matrix user to send alerts using token auth.
• Configurable room per alert receiver.
• Automatic joining of configured rooms. Private rooms require an invite.
• Secret key authentication with Alertmanager.
• HTML formatted messages.
• Optionally mentions @room on firing alerts

Whether running manually or via the Docker image, the configuration is set via environment variables. When running manually, copy .env.default into .env, set the values and they will be loaded automatically. When using the Docker image, set the environment variables when running the container.

The Docker image jaywink/matrix-alertmanager:latest is the easiest way to get the service running. Ensure you set the required environment variables listed in .env.default in this repository.

You will need to configure a webhook receiver in Alertmanager. It should looks something like this:

receivers:
- name: 'myreceiver'
  webhook_configs:
  - url: 'https://my-matrix-alertmanager.tld/alerts?secret=veryverysecretkeyhere'

The secret key obviously should match the one in the alertmanager configuration.

Alternatively, put the secret in a separate file and use basic auth with username alertmanager:

receivers:
- name: 'myreceiver'
  webhook_configs:
  - url: 'https://my-matrix-alertmanager.tld/alerts'
    http_config:
      basic_auth:
        username: alertmanager
        password_file: /path/to/password.secret

Add some styling to your prometheus rules

rules:
- alert: High Memory Usage of Container
  annotations:
    description: Container named <strong>{{\$labels.container_name}}</strong> in <strong>{{\$labels.pod_name}}</strong> in <strong>{{\$labels.namespace}}</strong> is using more than 75% of Memory Limit
  expr: |
    ((( sum(container_memory_usage_bytes{image!=\"\",container_name!=\"POD\", namespace!=\"kube-system\"}) by (namespace,container_name,pod_name, instance)  / sum(container_spec_memory_limit_bytes{image!=\"\",container_name!=\"POD\",namespace!=\"kube-system\"}) by (namespace,container_name,pod_name, instance) ) * 100 ) < +Inf ) > 75
  for: 5m
  labels:
    team: dev

NOTE! Currently, the bot cannot talk HTTPS, so you need to have a reverse proxy in place to terminate SSL, or use unsecure unencrypted connections.

• Registering an account instead of having to use an existing account

Node 20, Express, Matrix JS SDK

Come chat in the https://matrix.to/#/#matrix-alertmanager:federator.dev room!

Jason Robinson / https://jasonrobinson.me / @jaywink:federator.dev

MIT