From 3301dbfe34dde5ff8e17fce802931cc52c92ca76 Mon Sep 17 00:00:00 2001
From: Andreas Wrede <andreas@wrede.ca>
Date: Mon, 4 May 2026 08:03:46 -0400
Subject: [PATCH] feat: owner Update/Delete buttons on Host Overview; purge
 stale alerts on reload

Host Overview (plugins.html): show Update and Delete buttons in the
host-right zone when the logged-in user is the host owner (or admin /
unauthenticated mode). Buttons link to /u?h=<host> and /d?h=<host>
with stopPropagation so they don't toggle the accordion; Delete prompts
for confirmation first.

ThresholdChecker.purge_stale_alerts(): removes alert states whose
metric_path has no matching threshold in the current config. Called
after startup pickle restore and after every SIGHUP config reload so
alerts orphaned by upgrades or config changes do not persist
indefinitely.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 hbd/server/http.py                |  1 +
 hbd/server/main.py                |  7 ++++++-
 hbd/server/templates/plugins.html | 29 +++++++++++++++++++++++++++++
 hbd/server/threshold.py           | 20 ++++++++++++++++++++
 4 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/hbd/server/http.py b/hbd/server/http.py
index 4ce5070..c40e3fe 100644
--- a/hbd/server/http.py
+++ b/hbd/server/http.py
@@ -537,6 +537,7 @@ async def start(
                 hosts_with_plugins.append({
                     "name": hostname,
                     "plugins": list(host.plugin_data.keys()),
+                    "is_owner": _can_own_host(current_user, host),
                 })
 
         tmpl = env.get_template("plugins.html")
diff --git a/hbd/server/main.py b/hbd/server/main.py
index 2c62688..95701bd 100644
--- a/hbd/server/main.py
+++ b/hbd/server/main.py
@@ -101,9 +101,10 @@ async def reload_configuration(config_obj, config_path, components):
             access = config_mod.get_host_access(new_config, hostname)
             host.apply_access(access["owner"], access["managers"], access["monitors"])
 
-        # Reload threshold checker
+        # Reload threshold checker and prune alerts orphaned by the new config
         if 'threshold_checker' in components:
             components['threshold_checker'].reload(new_config)
+            components['threshold_checker'].purge_stale_alerts(hbdclass)
         
         # Note: Changes to the following require restart:
         # - hb_port, hbd_port, ws_port (already bound)
@@ -241,6 +242,10 @@ async def _run_async(config, config_path=None):
     )
     udp.restore_connection_timers(hbdclass, restore_ctx)
 
+    # Drop alert states that no longer have a matching threshold (stale after
+    # upgrade or config change between runs).
+    threshold_checker.purge_stale_alerts(hbdclass)
+
     # HTTP server (asyncio-based via aiohttp)
     try:
         http_task = asyncio.create_task(
diff --git a/hbd/server/templates/plugins.html b/hbd/server/templates/plugins.html
index 41f1ff2..a74de89 100644
--- a/hbd/server/templates/plugins.html
+++ b/hbd/server/templates/plugins.html
@@ -131,6 +131,27 @@
       text-overflow: ellipsis;
     }
 
+    .host-action-btn {
+      font-size: 0.75em;
+      font-weight: bold;
+      padding: 3px 10px;
+      border-radius: 4px;
+      border: none;
+      cursor: pointer;
+      text-decoration: none;
+      white-space: nowrap;
+    }
+    .host-action-btn.update-btn {
+      background: #e3f2fd;
+      color: #1565c0;
+    }
+    .host-action-btn.update-btn:hover { background: #bbdefb; }
+    .host-action-btn.delete-btn {
+      background: #ffebee;
+      color: #c62828;
+    }
+    .host-action-btn.delete-btn:hover { background: #ffcdd2; }
+
     /* ── Host body ──────────────────────────────────────────────── */
 
     .host-body {
@@ -379,6 +400,14 @@
               <span class="nagios-badge" id="nagios-badge-{{ host.name }}">—</span>
               {% endif %}
               <span class="os-label" id="os-label-{{ host.name }}"></span>
+              {% if host.is_owner %}
+              <a class="host-action-btn update-btn"
+                 href="/u?h={{ host.name }}"
+                 onclick="event.stopPropagation()">Update</a>
+              <a class="host-action-btn delete-btn"
+                 href="/d?h={{ host.name }}"
+                 onclick="event.stopPropagation(); return confirm('Delete host {{ host.name }}?')">Delete</a>
+              {% endif %}
             </div>
           </div>
 
diff --git a/hbd/server/threshold.py b/hbd/server/threshold.py
index fa4f5a1..9d86a00 100644
--- a/hbd/server/threshold.py
+++ b/hbd/server/threshold.py
@@ -1276,6 +1276,26 @@ class ThresholdChecker:
             alert_state.last_notification = now
             alert_state.notification_count += 1
     
+    def purge_stale_alerts(self, hbdclass) -> None:
+        """Remove alert states that have no matching threshold configuration.
+
+        Called after startup (pickle restore) and after each config reload so
+        that alerts orphaned by configuration changes do not linger forever.
+        Alerts whose metric_path is not present in the current threshold config
+        for that host are silently dropped.
+        """
+        for hostname, host in hbdclass.Host.hosts.items():
+            if not host.alert_states:
+                continue
+            configured = self.get_thresholds_for_host(hostname)
+            stale = [mp for mp in host.alert_states if mp not in configured]
+            for mp in stale:
+                logger.info(
+                    "Purging stale alert state for %s / %s (no threshold configured)",
+                    hostname, mp,
+                )
+                del host.alert_states[mp]
+
     def get_active_alerts(self, alert_states: Dict[str, AlertState]) -> list:
         """
         Get all currently active (non-OK) alerts.