feat(alertmanager): add more info in notifications

Map status, priority, tags and runbook.

system/monitoring-system/files/webhook-transformer/alertmanager-to-ntfy.jsonnet

@@ -1,8 +1,44 @@
+local get_tags(status, severity) =
+  // https://docs.ntfy.sh/emojis
+  if status == "resolved" then
+    ["tada"]
+  else
+    std.get({
+      critical: ["rotating_light"],
+      warning: ["warning"],
+      info: ["newspaper"],
+    }, severity, ["question"]);
+
+local get_priority(status, severity) =
+  // https://docs.ntfy.sh/publish/#message-priority
+  if status == "resolved" then
+    2
+  else
+    std.get({
+      critical: 5,
+      warning: 3,
+      info: 1,
+    }, severity, 3);
+
+local get_actions(status, annotations) =
+  // https://docs.ntfy.sh/publish/#action-buttons
+  if status == "resolved" || !("runbook_url" in annotations) then
+    []
+  else
+    [
+      {
+        action: "view",
+        label: "Open runbook",
+        url: annotations.runbook_url,
+      },
+    ];
+
+// TODO support multiple alerts
 {
-  "topic": env.NTFY_TOPIC,
-  "title": body.alerts[0].labels.alertname, // TODO support multiple alerts
-  "message": body.alerts[0].annotations.description,
-  "tags": [],
-  "priority": 3,
-  "actions": []
+  topic: env.NTFY_TOPIC,
+  title: "[" + std.asciiUpper(body.status) + "] " + body.alerts[0].labels.alertname,
+  message: body.alerts[0].annotations.description,
+  tags: get_tags(body.status, body.alerts[0].labels.severity),
+  priority: get_priority(body.status, body.alerts[0].labels.severity),
+  actions: get_actions(body.status, body.alerts[0].annotations),
 }