From 81544c8a3975224420be1dd0204ad3bb935f2a93 Mon Sep 17 00:00:00 2001
From: MayMeow <3164256+MayMeow@users.noreply.github.com>
Date: Sun, 9 Nov 2025 17:57:20 +0100
Subject: [PATCH] Fix Group monitors to send notification after reaching
 maximum retires count (#6286)

Co-authored-by: Frank Elsinga <frank@elsinga.de>
---
 server/monitor-types/group.js | 82 ++++++++++++++++++++++++-----------
 1 file changed, 57 insertions(+), 25 deletions(-)

diff --git a/server/monitor-types/group.js b/server/monitor-types/group.js
index 28d0443d4..8372b4f17 100644
--- a/server/monitor-types/group.js
+++ b/server/monitor-types/group.js
@@ -11,35 +11,67 @@ class GroupMonitorType extends MonitorType {
     async check(monitor, heartbeat, _server) {
         const children = await Monitor.getChildren(monitor.id);
 
-        if (children.length > 0) {
-            heartbeat.status = UP;
-            heartbeat.msg = "All children up and running";
-            for (const child of children) {
-                if (!child.active) {
-                    // Ignore inactive childs
-                    continue;
-                }
-                const lastBeat = await Monitor.getPreviousHeartbeat(child.id);
-
-                // Only change state if the monitor is in worse conditions then the ones before
-                // lastBeat.status could be null
-                if (!lastBeat) {
-                    heartbeat.status = PENDING;
-                } else if (heartbeat.status === UP && (lastBeat.status === PENDING || lastBeat.status === DOWN)) {
-                    heartbeat.status = lastBeat.status;
-                } else if (heartbeat.status === PENDING && lastBeat.status === DOWN) {
-                    heartbeat.status = lastBeat.status;
-                }
-            }
-
-            if (heartbeat.status !== UP) {
-                heartbeat.msg = "Child inaccessible";
-            }
-        } else {
+        if (children.length === 0) {
             // Set status pending if group is empty
             heartbeat.status = PENDING;
             heartbeat.msg = "Group empty";
+            return;
         }
+
+        let worstStatus = UP;
+        const downChildren = [];
+        const pendingChildren = [];
+
+        for (const child of children) {
+            if (!child.active) {
+                // Ignore inactive (=paused) children
+                continue;
+            }
+
+            const label = child.name || `#${child.id}`;
+            const lastBeat = await Monitor.getPreviousHeartbeat(child.id);
+
+            if (!lastBeat) {
+                if (worstStatus === UP) {
+                    worstStatus = PENDING;
+                }
+                pendingChildren.push(label);
+                continue;
+            }
+
+            if (lastBeat.status === DOWN) {
+                worstStatus = DOWN;
+                downChildren.push(label);
+            } else if (lastBeat.status === PENDING) {
+                if (worstStatus !== DOWN) {
+                    worstStatus = PENDING;
+                }
+                pendingChildren.push(label);
+            }
+        }
+
+        if (worstStatus === UP) {
+            heartbeat.status = UP;
+            heartbeat.msg = "All children up and running";
+            return;
+        }
+
+        if (worstStatus === PENDING) {
+            heartbeat.status = PENDING;
+            heartbeat.msg = `Pending child monitors: ${pendingChildren.join(", ")}`;
+            return;
+        }
+
+        heartbeat.status = DOWN;
+
+        let message = `Child monitors down: ${downChildren.join(", ")}`;
+
+        if (pendingChildren.length > 0) {
+            message += `; pending: ${pendingChildren.join(", ")}`;
+        }
+
+        // Throw to leverage the generic retry handling and notification flow
+        throw new Error(message);
     }
 }