Generate silence url for prom alertmanager alerts

ops_bot/alertmanager.py

@@ -29,7 +29,9 @@ def prometheus_alert_to_markdown(
     ignore_labels = ["grafana_folder"]
 
     logging.debug(f"alertmanager payload: {alert_data}")
+    externalURL = alert_data.get("externalURL")
     for alert in alert_data["alerts"]:
+        alertname = alert["labels"]["alertname"]
         title = alert["labels"]["alertname"]
         summary = alert["annotations"].get("summary")
         description = alert["annotations"].get("description")
@@ -70,6 +72,10 @@ def prometheus_alert_to_markdown(
         dashboardURL = alert.get("dashboardURL")
         silenceURL = alert.get("silenceURL")
         actions = []
+        if not silenceURL and externalURL:
+            silence_filter = f"alertname%3D%22{alertname}%22"
+            silence_filter = "{" + silence_filter + "}"
+            silenceURL = f"{externalURL}/#/silences/new?filter={silence_filter}"
         if silenceURL:
             actions.append(f"[🔕 Mute]({silenceURL})")
         if runbookURL:

tests/test_alertmanager.py

@@ -69,4 +69,6 @@ def test_alertmanager():
         and "webserver.example.com" in formatted
         and "Instance webserver.example.com down" in formatted
         and "critical" in formatted
+        and "https://alert.example/#/silences/new?filter={alertname%3D%22InstanceDown%22}"
+        in formatted
     )