Customizing Alertmanager Slack message notification popups

[Pietro Staheli]

Hi,

Is there a way to influence what is shown in the Slack notification popup when Alertmanager sends an alert to a Slack channel? Right now, the name of the Alertmanager which is sending the alert is shown in the notification (on both Slack for Android and Desktop MacOS), which is little confusing and misleading. The message in the Slack application displays the info I want, it's only the notification that I'd like to change.

See screenshot, I would like to have the affected host visible, but not the alertmanager. Is there a label I could overwrite here? I don't see anything that would be in the template, config below:

alertmanager.yml:

receivers:
- name: slack-notifications-infra-production
  slack_configs:
  - channel: '#infra-alerting'
    api_url: 'https://hooks.slack.com/services/BLA/FASEL'
    send_resolved: true
    username: 'anna'
    color: '{{ template "slack.color" . }}'
    title: '{{ template "slack.title" . }}'
    text: '{{ template "slack.text" . }}'

alertmanager_templates/slack.tmpl:
{{/* Alertmanager Silence link */}}
{{ define "__alert_silence_link" -}}
    {{ .ExternalURL }}/#/silences/new?filter=%7B
    {{- range .CommonLabels.SortedPairs -}}
        {{- if ne .Name "alertname" -}}
            {{- .Name }}%3D"{{- .Value -}}"%2C%20
        {{- end -}}
    {{- end -}}
    alertname%3D"{{- .CommonLabels.alertname -}}"%7D
{{- end }}

{{/* Severity of the alert */}}
{{ define "__alert_severity" -}}
    {{- if eq .CommonLabels.severity "critical" -}}
    *Severity:* `Critical`
    {{- else if eq .CommonLabels.severity "warning" -}}
    *Severity:* `Warning`
    {{- else if eq .CommonLabels.severity "info" -}}
    *Severity:* `Info`
    {{- else -}}
    *Severity:* :question: {{ .CommonLabels.severity }}
    {{- end }}
{{- end }}

{{/* Title of the Slack alert */}}
{{ define "slack.title" -}}
  [{{ .Status | toUpper -}}
  {{ if eq .Status "firing" }}:{{ .Alerts.Firing | len }}{{- end -}}
  ] {{ .CommonLabels.alertname }}
{{- end }}


{{/* Color of Slack attachment (appears as line next to alert )*/}}
{{ define "slack.color" -}}
    {{ if eq .Status "firing" -}}
        {{ if eq .CommonLabels.severity "warning" -}}
            warning
        {{- else if eq .CommonLabels.severity "critical" -}}
            danger
        {{- else -}}
            #439FE0
        {{- end -}}
    {{ else -}}
    good
    {{- end }}
{{- end }}

{{/* The text to display in the alert */}}
{{ define "slack.text" -}}

    {{ template "__alert_severity" . }}
    {{- if (index .Alerts 0).Annotations.summary }}
    {{- "\n" -}}
    *Summary:* {{ (index .Alerts 0).Annotations.summary }}
    {{- end }}

    {{ range .Alerts }}

        {{- if .Annotations.description }}
        {{- "\n" -}}
        {{ .Annotations.description }}
        {{- "\n" -}}
        {{- end }}
        {{- if .Annotations.message }}
        {{- "\n" -}}
        {{ .Annotations.message }}
        {{- "\n" -}}
        {{- end }}

    {{- end }}

{{- end }}

Thanks,
Pietro