Prometheus - better slack messages

alertmanager.yml

receivers:
- name: default
  slack_configs:
  - api_url: https://hooks.slack.com/services/...
    channel: alerts
    send_resolved: true
    title: '' # important, put empty string here
    text: '{{ template "slack.shamil.text" . }}'

slack.tmpl

{{/* vim: set filetype=mustache: */}}

{{/*
Compose slack text message per firing/resolved alert
*/}}
{{- define "slack.shamil.text" -}}
{{- if gt (len .Alerts.Firing) 0 }}
<{{ .ExternalURL }}|*FIRING ({{ .Alerts.Firing | len }})*>
{{ range .Alerts.Firing }}
><{{ .GeneratorURL }}|{{ join ", " .Labels.Values }}>
>{{ .Annotations.description }}
{{ end }}
{{- end -}}
{{- if gt (len .Alerts.Resolved) 0 }}
*RESOLVED ({{ .Alerts.Resolved | len }})*
{{ range .Alerts.Resolved }}
><{{ .GeneratorURL }}|{{ join ", " .Labels.Values }}>
>{{ .Annotations.description }}
{{ end }}
{{- end -}}
{{- end -}}

zresult.png