Grafana alert template language

I have talked about Prometheus and Grafana before. I currently have onse prom scraping two servers and one grafana where I have a few dashboards and many panels. Now I started using alers and it's working great: my biggest issues are too much wind (yes, really), too hot (also really) and disk space (always short).

So I'm getting a few alerts per day, currently mostly about weather. But by default, alerts look like this:

**Firing**

Value: A=29.6, C=1
Labels:
- alertname = Temperature
- grafana_folder = Critical
- instance = server:9100
- job = node
- source = WG_IMARSE62
Annotations:
Source: http://localhost:3000/alerting/grafana/fenz0y2eyv0u8b/view?orgId=1
Silence: http://localhost:3000/alerting/silence/new?alertmanager=grafana&matcher=__alert_rule_uid__%3Dfenz0y2eyv0u8b&matcher=instance%3Dserver%3A9100&matcher=job%3Dnode&matcher=source%3DWG_IMARSE62&orgId=1
Dashboard: http://localhost:3000/d/be93c7dhu0lq8f?from=1750071590000&orgId=1&to=1750089925094
Panel: http://localhost:3000/d/be93c7dhu0lq8f?from=1750071590000&orgId=1&to=1750089925094&viewPanel=1

Value: A=29.8, C=1
Labels:
- alertname = Temperature
- grafana_folder = Critical
- instance = server:9100
- job = node
- source = yr_no
Annotations:
Source: http://localhost:3000/alerting/grafana/fenz0y2eyv0u8b/view?orgId=1
Silence: http://localhost:3000/alerting/silence/new?alertmanager=grafana&matcher=__alert_rule_uid__%3Dfenz0y2eyv0u8b&matcher=instance%3Dserver%3A9100&matcher=job%3Dnode&matcher=source%3Dyr_no&orgId=1
Dashboard: http://localhost:3000/d/be93c7dhu0lq8f?from=1750069190000&orgId=1&to=1750089925094
Panel: http://localhost:3000/d/be93c7dhu0lq8f?from=1750069190000&orgId=1&to=1750089925094&viewPanel=1

Many things are ugly here:

• Alert name and current value are not first on the text, so I have to open the contact point app instead of just reading it from the notification, which is faster.
• Links do not have the right domain name (this should be simple configuration error).
• It's too generic and includes more info than I actually need to action on these¹, which could be confusing if you're awaken at 3AM after the baby has cried all night long and/or you probably hasd one or two beers more than you should have⁴.

So of course we have to customize the alerts², but let's see the docs: Template notifications³. It describes a few can's and can't's⁷ and then BAM: an example. It shows what a rendered alert would look like, but utterly fails to explain the template language. That's I will try to do here.

The first thing you have to know about these templates is that they use the template language that comes in golang's stdlib⁵. You should start reading that, which is a lot already.

Second, you should be aware of the default templates that grafana provides, which comes from Grafana's alertmanager fork⁶, and that every Contact Point Integration type has its own template. See also the ["Built-in Templates" in the "Notification Templates" tab on the "Contact points" section in your Grafana]³(https://example.com:3000/alerting/notifications?search=&tab=templates) (change the server name and possibly port).

Third, you should know what data objects are available to those templates.