shack/prometheus: add custom shack template

krebs/2configs/shack/prometheus/alertmanager-telegram.nix

@@ -8,10 +8,10 @@
       DynamicUser = true;
       StateDirectory = "alertbot";
       ExecStart = ''${pkgs.alertmanager-bot-telegram}/bin/alertmanager-bot \
-        --alertmanager.url=http://alert.prometheus.shack --log.level=info \
+        --alertmanager.url=http://alert.prometheus.shack --log.level=debug \
         --store=bolt --bolt.path=/var/lib/alertbot/bot.db \
         --listen.addr="0.0.0.0:16320" \
-        --template.paths=${pkgs.alertmanager-bot-telegram}/templates/default.tmpl'';
+        --template.paths=${./templates}/shack.tmpl'';
     };
   };
 }

krebs/2configs/shack/prometheus/templates/shack.tmpl

@@ -0,0 +1,25 @@
+{{ define "telegram.default" }}
+{{range .Alerts -}}
+{{ $severity := index .Labels "severity" }}
+{{ $desc := "No Description" }}
+{{ if eq .Status "firing" }}
+  {{ $desc = index .Annotations "description" }}
+  {{- if eq $severity "critical" -}}
+    <i><u><b>[CRITICAL]</b></u></i>
+  {{- else if eq $severity "warning" -}}
+    <u><b>[WARNING]</b></u>
+  {{- else -}}
+    <b>[{{ $severity }}]</b>
+  {{- end -}}
+{{ else -}}
+  {{ $desc = "The issue has been resolved" }}
+  <del>[RESOLVED]</del>
+{{- end }} {{ index .Labels "alertname"}}: {{ index .Annotations "summary"}}
+
+{{ $desc }}
+
+Alert Links:
+* <a href="{{ index .Annotations "url"}}">Grafana</a>
+* <a href="{{ .GeneratorURL }}">Source</a>
+{{end -}}
+{{end}}