feat: plugin fault isolation notices + NUT managed mode fixes

Plugin failures:
- Track load-time failures in _FAILED_PLUGINS dict with human-readable reasons
- Inject plugin_failures into all templates via context processor
- Show admin-only warning banner in base.html when any plugin fails to load
- Show inline failure notice per plugin card in Settings → Plugins

NUT managed mode:
- entrypoint.sh: make nut_setup.py failure non-fatal so the container starts
  even if nut_ups_host isn't set yet (allows fixing config via UI)
- save_plugins: when nut_managed is enabled, auto-set nut_host=localhost so
  the plugin connects to the managed NUT instance without extra manual config

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

entrypoint.sh

@@ -24,22 +24,31 @@ set -e
 NUT_MANAGED_JSON="/data/nut_managed.json"
 
 if [ "${NUT_MANAGED:-0}" = "1" ] || [ -f "$NUT_MANAGED_JSON" ]; then
+    NUT_OK=1
     if [ -f "$NUT_MANAGED_JSON" ]; then
         echo "[entrypoint] Found $NUT_MANAGED_JSON — configuring NUT from settings..."
-        python3 /app/fabledscryer/nut_setup.py --from-file "$NUT_MANAGED_JSON"
+        python3 /app/fabledscryer/nut_setup.py --from-file "$NUT_MANAGED_JSON" || {
+            echo "[entrypoint] Warning: NUT config failed — UPS host may not be set yet. Skipping NUT startup."
+            NUT_OK=0
+        }
     else
         echo "[entrypoint] NUT_MANAGED=1 — configuring NUT from environment..."
-        python3 /app/fabledscryer/nut_setup.py
+        python3 /app/fabledscryer/nut_setup.py || {
+            echo "[entrypoint] Warning: NUT config failed — check NUT_UPS_HOST. Skipping NUT startup."
+            NUT_OK=0
+        }
     fi
 
-    echo "[entrypoint] Starting NUT driver..."
+    if [ "$NUT_OK" = "1" ]; then
-    /sbin/upsdrvctl start || echo "[entrypoint] Warning: upsdrvctl returned non-zero"
+        echo "[entrypoint] Starting NUT driver..."
+        /sbin/upsdrvctl start || echo "[entrypoint] Warning: upsdrvctl returned non-zero"
 
-    echo "[entrypoint] Starting NUT daemon..."
+        echo "[entrypoint] Starting NUT daemon..."
-    /sbin/upsd || echo "[entrypoint] Warning: upsd returned non-zero"
+        /sbin/upsd || echo "[entrypoint] Warning: upsd returned non-zero"
 
-    sleep 1
+        sleep 1
-    echo "[entrypoint] NUT ready on 127.0.0.1:3493."
+        echo "[entrypoint] NUT ready on 127.0.0.1:3493."
+    fi
 fi
 
 exec gosu app "$@"

fabledscryer/app.py

@@ -122,7 +122,13 @@ def create_app(
         from .core.plugin_manager import load_plugins
         load_plugins(app)
 
-    # ── 10. Share-token middleware ─────────────────────────────────────────────
+    # ── 10. Template context: inject plugin_failures into every response ───────
+    @app.context_processor
+    def _inject_plugin_failures():
+        from .core.plugin_manager import get_plugin_failures
+        return {"plugin_failures": get_plugin_failures()}
+
+    # ── 11. Share-token middleware ─────────────────────────────────────────────
     @app.before_request
     async def _validate_share_token():
         """If ?s=<token> is present, validate it and set g.share_viewer."""

fabledscryer/core/plugin_manager.py

@@ -22,6 +22,14 @@ logger = logging.getLogger(__name__)
 # whether to register a blueprint (new plugin) or skip it (already registered).
 _LOADED_PLUGINS: set[str] = set()
 
+# Track plugins that failed to load: name → human-readable reason.
+_FAILED_PLUGINS: dict[str, str] = {}
+
+
+def get_plugin_failures() -> dict[str, str]:
+    """Return a copy of the failed-plugin registry (name → error message)."""
+    return dict(_FAILED_PLUGINS)
+
 
 def _import_plugin(name: str, plugin_path: Path):
     """Load a plugin module by file path, avoiding sys.modules stdlib collisions.
@@ -86,23 +94,29 @@ def load_plugins(app: "Quart") -> None:
 
         plugin_path = plugin_dir / name
         if not plugin_path.exists():
+            _FAILED_PLUGINS[name] = f"Plugin directory not found: {plugin_path}"
             logger.error("Plugin %r: directory %s not found, skipping", name, plugin_path)
             continue
 
         # Load and validate plugin.yaml
         yaml_path = plugin_path / "plugin.yaml"
         if not yaml_path.exists():
+            _FAILED_PLUGINS[name] = "plugin.yaml not found"
             logger.error("Plugin %r: plugin.yaml not found, skipping", name)
             continue
 
         try:
             with yaml_path.open() as f:
                 meta = yaml.safe_load(f) or {}
-        except Exception:
+        except Exception as exc:
+            _FAILED_PLUGINS[name] = f"Failed to read plugin.yaml: {exc}"
             logger.exception("Plugin %r: failed to read plugin.yaml, skipping", name)
             continue
 
         if meta.get("name") != name:
+            _FAILED_PLUGINS[name] = (
+                f"plugin.yaml name {meta.get('name')!r} does not match directory name"
+            )
             logger.error(
                 "Plugin %r: plugin.yaml name=%r does not match directory name, skipping",
                 name, meta.get("name"),
@@ -113,12 +127,16 @@ def load_plugins(app: "Quart") -> None:
         if min_ver:
             try:
                 if Version(fabledscryer.__version__) < Version(min_ver):
+                    _FAILED_PLUGINS[name] = (
+                        f"Requires fabledscryer>={min_ver}, running {fabledscryer.__version__}"
+                    )
                     logger.error(
                         "Plugin %r: requires fabledscryer>=%s but running %s, skipping",
                         name, min_ver, fabledscryer.__version__,
                     )
                     continue
-            except Exception:
+            except Exception as exc:
+                _FAILED_PLUGINS[name] = f"Invalid min_app_version {min_ver!r}: {exc}"
                 logger.exception("Plugin %r: invalid min_app_version %r, skipping", name, min_ver)
                 continue
 
@@ -142,15 +160,18 @@ def load_plugins(app: "Quart") -> None:
         # Import the plugin package (file-path load avoids stdlib name collisions)
         try:
             module = _import_plugin(name, plugin_path)
-        except Exception:
+        except Exception as exc:
+            _FAILED_PLUGINS[name] = f"Import error: {exc}"
             logger.exception("Plugin %r: import failed, skipping", name)
             continue
 
         # Validate required exports
         if not hasattr(module, "setup"):
+            _FAILED_PLUGINS[name] = "Missing required export: setup()"
             logger.error("Plugin %r: missing required export 'setup', skipping", name)
             continue
         if not hasattr(module, "get_scheduled_tasks"):
+            _FAILED_PLUGINS[name] = "Missing required export: get_scheduled_tasks()"
             logger.error(
                 "Plugin %r: missing required export 'get_scheduled_tasks', skipping", name
             )
@@ -159,7 +180,8 @@ def load_plugins(app: "Quart") -> None:
         # Call setup
         try:
             module.setup(app)
-        except Exception:
+        except Exception as exc:
+            _FAILED_PLUGINS[name] = f"setup() failed: {exc}"
             logger.exception("Plugin %r: setup() raised, skipping", name)
             continue
 
@@ -169,17 +191,22 @@ def load_plugins(app: "Quart") -> None:
                 bp = module.get_blueprint()
                 app.register_blueprint(bp, url_prefix=f"/plugins/{name}")
                 logger.info("Plugin %r: blueprint registered at /plugins/%s/", name, name)
-            except Exception:
+            except Exception as exc:
+                _FAILED_PLUGINS[name] = f"Blueprint registration failed: {exc}"
                 logger.exception("Plugin %r: get_blueprint() raised", name)
+                continue
 
         # Register scheduled tasks
         try:
             tasks = module.get_scheduled_tasks()
             app._task_registry.extend(tasks)
             logger.info("Plugin %r: registered %d scheduled task(s)", name, len(tasks))
-        except Exception:
+        except Exception as exc:
+            _FAILED_PLUGINS[name] = f"get_scheduled_tasks() failed: {exc}"
             logger.exception("Plugin %r: get_scheduled_tasks() raised", name)
+            continue
 
+        _FAILED_PLUGINS.pop(name, None)  # clear any stale failure from a previous reload attempt
         _LOADED_PLUGINS.add(name)
         logger.info("Plugin %r loaded (v%s)", name, meta.get("version", "?"))
 

fabledscryer/settings/routes.py

@@ -408,6 +408,12 @@ async def save_plugins():
                                 plugin_cfg[cfg_key] = default_val
                         else:
                             plugin_cfg[cfg_key] = raw_val
+                # Managed NUT: when nut_managed is on, the NUT daemon runs in this
+                # container — force nut_host/port to localhost so the plugin
+                # connects to it automatically without manual config.
+                if name == "ups" and plugin_cfg.get("nut_managed"):
+                    plugin_cfg["nut_host"] = "localhost"
+                    plugin_cfg["nut_port"] = 3493
                 await set_setting(db, f"plugin.{name}", plugin_cfg)
     await _reload_app_config()
     from fabledscryer.core.plugin_index import clear_catalog_cache

fabledscryer/templates/base.html

@@ -243,6 +243,20 @@ function setTimeRange(val) {
 </script>
 
     <main>
+        {% if plugin_failures and session.user_role == 'admin' %}
+        <div style="background:color-mix(in srgb,var(--yellow) 12%,var(--bg-elevated));
+                    border:1px solid color-mix(in srgb,var(--yellow) 35%,var(--border));
+                    border-radius:6px;padding:0.6rem 1rem;margin-bottom:1rem;
+                    font-size:0.84rem;display:flex;align-items:flex-start;gap:0.6rem;">
+            <span style="color:var(--yellow);flex-shrink:0;">⚠</span>
+            <span>
+                <strong style="color:var(--text);">
+                    {{ plugin_failures | length }} plugin{{ 's' if plugin_failures | length != 1 }} failed to load.
+                </strong>
+                <a href="/settings/plugins/" style="color:var(--accent);margin-left:0.4rem;">View details →</a>
+            </span>
+        </div>
+        {% endif %}
         {% if error %}
         <div class="alert alert-error">{{ error }}</div>
         {% endif %}

fabledscryer/templates/settings/plugins.html

@@ -62,6 +62,20 @@
       </label>
     </div>
 
+    {# Failure notice — shown when this plugin failed to load #}
+    {% set fail_reason = plugin_failures.get(plugin._dir) %}
+    {% if fail_reason %}
+    <div style="display:flex;align-items:flex-start;gap:0.5rem;padding:0.5rem 0.75rem;
+                margin-top:0.6rem;background:color-mix(in srgb,var(--red) 10%,var(--bg));
+                border:1px solid color-mix(in srgb,var(--red) 30%,var(--border));
+                border-radius:5px;font-size:0.82rem;">
+      <span style="color:var(--red);flex-shrink:0;">✕</span>
+      <span><strong style="color:var(--red);">Failed to load</strong>
+        <span style="color:var(--text-muted);margin-left:0.3rem;">— {{ fail_reason }}</span>
+      </span>
+    </div>
+    {% endif %}
+
     {# Config fields — only shown when there are config keys #}
     {% if plugin.get('config') %}
     <div style="border-top:1px solid var(--border);padding-top:1rem;display:grid;gap:0.6rem;">