config.yml

---
route:
  group_wait: 10s
  group_interval: 30s
  repeat_interval: 10m
  receiver: "slack"
  routes:
    - receiver: "slack"
      group_wait: 10s
      match_re:
        severity: critical|warning
      continue: true

receivers:
  - name: "slack"
    slack_configs:
      - api_url: 'https://yourslackhookurl.whatever/cddsfasfdas/adsfafdaf/aasdfafddafa'
        send_resolved: true
        channel: 'somechannel'
        icon_url: https://avatars3.githubusercontent.com/u/3380462
        title: |
         [{{ .Status | toUpper }}{{ if eq .Status "firing" }}:{{ .Alerts.Firing | len }}{{ end }}] {{ .CommonLabels.alertname }} for {{ .CommonLabels.job }}
         {{- if gt (len .CommonLabels) (len .GroupLabels) -}}
           {{" "}}(
           {{- with .CommonLabels.Remove .GroupLabels.Names }}
             {{- range $index, $label := .SortedPairs -}}
               {{ if $index }}, {{ end }}
               {{- $label.Name }}="{{ $label.Value -}}"
             {{- end }}
           {{- end -}}
           )
         {{- end }}
        text: |
         {{ range .Alerts -}}
         *Alert:* {{ .Annotations.title }}{{ if .Labels.severity }} - `{{ .Labels.severity }}`{{ end }}

         *Description:* {{ .Annotations.description }}

         *Details:*
           {{ range .Labels.SortedPairs }} • *{{ .Name }}:* `{{ .Value }}`
           {{ end }}
         {{ end }}