alertmanager.yml

global:
  resolve_timeout: 5m
  smtp_smarthost: '${SMTP_HOST}:${SMTP_PORT}'
  smtp_from: '${SMTP_FROM}'
  smtp_auth_username: '${SMTP_USERNAME}'
  smtp_auth_password: '${SMTP_PASSWORD}'
  smtp_require_tls: true

route:
  receiver: slack-default
  group_by: [alertname, severity]
  group_wait: 30s
  group_interval: 5m
  repeat_interval: 4h
  routes:
    - matchers:
        - severity = critical
      receiver: pagerduty
      continue: true
    - matchers:
        - severity = critical
      receiver: email-oncall
      continue: false

receivers:
  - name: slack-default
    slack_configs:
      - api_url: ${SLACK_WEBHOOK_URL}
        channel: '#alerts'
        send_resolved: true
        title: '[{{ .Status | toUpper }}] {{ .CommonLabels.alertname }}'
        text: |
          {{ range .Alerts }}
          *Severity:* {{ .Labels.severity }}
          *Summary:* {{ .Annotations.summary }}
          *Description:* {{ .Annotations.description }}
          {{ end }}

  - name: pagerduty
    pagerduty_configs:
      - service_key: ${PAGERDUTY_SERVICE_KEY}
        send_resolved: true
        description: '{{ .CommonAnnotations.summary }}'

  - name: email-oncall
    email_configs:
      - to: '${ALERT_EMAIL_TO}'
        send_resolved: true
        headers:
          Subject: '[{{ .Status | toUpper }}] {{ .CommonLabels.alertname }} — TeachLink'
        html: |
          <h3>{{ .CommonLabels.alertname }}</h3>
          <p><strong>Status:</strong> {{ .Status | toUpper }}</p>
          {{ range .Alerts }}
          <p><strong>Severity:</strong> {{ .Labels.severity }}<br>
          <strong>Summary:</strong> {{ .Annotations.summary }}<br>
          <strong>Description:</strong> {{ .Annotations.description }}</p>
          {{ end }}

inhibit_rules:
  - source_matchers: [severity = critical]
    target_matchers: [severity = warning]
    equal: [alertname, service]