prometheus/gmp/alertmanager.yaml

global:
  resolve_timeout: 1m

route:
  receiver: 'slack-notifications'
  group_by: [alertname, job, app]

receivers:
- name: 'slack-notifications'
  slack_configs:
  - api_url: SLACK_WEBHOOK_URL
    send_resolved: true
    title: |
      [{{ .Status | toUpper -}}
      {{ if eq .Status "firing" }}:{{ .Alerts.Firing | len }}{{- end -}}
      ] {{ .CommonLabels.alertname }}
    text: |
      {{- if eq .CommonLabels.severity "critical" -}}
      *Severity:* `Critical` :red_circle:
      {{- else if eq .CommonLabels.severity "warning" -}}
      *Severity:* `Warning` :warning:
      {{- else if eq .CommonLabels.severity "info" -}}
      *Severity:* `Info` :information_source:
      {{- else -}}
      *Severity:* `Unknown` :interrobang: {{ .CommonLabels.severity }}
      {{- end }}
      {{- if (index .Alerts 0).Annotations.summary }}
      {{- "\n" -}}
      *Summary:* {{ (index .Alerts 0).Annotations.summary }}
      {{- end }}
      {{- if (index .Alerts 0).Labels.namespace }}
      {{- "\n" -}}
      *Namespace:* `{{ (index .Alerts 0).Labels.namespace }}`
      {{- end }}
      {{ range .Alerts }}
          {{- if .Annotations.description }}
          {{- "\n" -}}
          {{ .Annotations.description }}
          {{- "\n" -}}
          {{- end }}
          {{- if .Annotations.message }}
          {{- "\n" -}}
          {{ .Annotations.message }}
          {{- "\n" -}}
          {{- end }}
      {{- end }}
    color: '{{ if eq .Status "firing" -}}{{ if eq .CommonLabels.severity "warning" -}}warning{{- else if eq .CommonLabels.severity "critical" -}}danger{{- else -}}#439FE0{{- end -}}{{ else -}}good{{- end }}'