feat: add background library sync thread with configurable interval to eliminate browser dependency for automatic scanning

Add SYNC_INTERVAL_SECONDS environment variable with default 1800 (30 minutes). Add library_cache global dict with rows/series/updated_at/error/ready fields and library_cache_lock for thread-safe access. Extract refresh_library_cache() function to update Radarr/Sonarr data with error handling that preserves last good snapshot during outages. Add background_library_sync() daemon

app.py

@@ -48,6 +48,7 @@ STORAGE_CACHE_SECONDS = int(os.environ.get("STORAGE_CACHE_SECONDS", "900"))
 SMART_ENABLED = os.environ.get("SMART_ENABLED", "false").lower() in {"1", "true", "yes", "on"}
 LOG_FILE = os.environ.get("LOG_FILE", "/data/media-max.log")
 LOG_RETENTION_HOURS = max(1, int(os.environ.get("LOG_RETENTION_HOURS", "6")))
+SYNC_INTERVAL_SECONDS = max(0, int(os.environ.get("SYNC_INTERVAL_SECONDS", "1800")))
 
 logging.basicConfig(level=os.environ.get("LOG_LEVEL", "INFO").upper(), format="%(asctime)s %(levelname)s %(message)s")
 log = logging.getLogger("media-max")
@@ -90,6 +91,8 @@ raid_log_state = None
 graphics_log_state = None
 graphics_process_log_state = None
 hardware_log_once = set()
+library_cache_lock = threading.Lock()
+library_cache = {"rows": [], "series": [], "updated_at": 0.0, "error": None, "ready": False}
 
 LANG_NAMES = {"de":"Deutsch", "deu":"Deutsch", "ger":"Deutsch", "en":"Englisch", "eng":"Englisch", "ja":"Japanisch", "jpn":"Japanisch", "ko":"Koreanisch", "kor":"Koreanisch", "fr":"Französisch", "fra":"Französisch", "fre":"Französisch", "es":"Spanisch", "spa":"Spanisch", "it":"Italienisch", "ita":"Italienisch", "ru":"Russisch", "rus":"Russisch", "zh":"Chinesisch", "zho":"Chinesisch", "chi":"Chinesisch", "und":"Unbekannt", "":"Unbekannt"}
 FLAGS = {"Deutsch":"🇩🇪", "Englisch":"🇬🇧", "Japanisch":"🇯🇵", "Koreanisch":"🇰🇷", "Französisch":"🇫🇷", "Spanisch":"🇪🇸", "Italienisch":"🇮🇹", "Russisch":"🇷🇺", "Chinesisch":"🇨🇳", "Unbekannt":"❓"}
@@ -960,7 +963,7 @@ def sonarr_groups():
                        "category":category_key, "category_label":category_label})
     return sorted(groups, key=lambda x: x["title"].lower())
 
-def start_scan(source, force=False):
+def start_scan(source, force=False, rows_snapshot=None, series_snapshot=None):
     with job_lock:
         if jobs[source]["state"] == "running" or (jobs[source]["state"] in ("done", "error") and not force): return
         jobs[source] = {"state":"running", "total":0, "done":0, "error":None}
@@ -968,16 +971,16 @@ def start_scan(source, force=False):
         try:
             paths = []
             if source == "radarr":
-                for row in radarr_rows():
+                for row in rows_snapshot if rows_snapshot is not None else radarr_rows():
                     if row["local_path"] != "—" and row["pending"]: paths.append(row["local_path"])
             elif source == "sonarr":
-                for group in sonarr_groups():
+                for group in series_snapshot if series_snapshot is not None else sonarr_groups():
                     paths.extend(r["local_path"] for r in group["episodes"] if r["local_path"] != "—" and r["pending"])
             else:
-                for row in radarr_rows():
+                for row in rows_snapshot if rows_snapshot is not None else radarr_rows():
                     if row["local_path"] != "—" and is_german_review_candidate(row) and not has_german_track(row): paths.append(row["local_path"])
                 if SONARR_URL and SONARR_API_KEY:
-                    for group in sonarr_groups():
+                    for group in series_snapshot if series_snapshot is not None else sonarr_groups():
                         paths.extend(r["local_path"] for r in group["episodes"] if r["local_path"] != "—" and is_german_review_candidate(r) and not has_german_track(r))
             with job_lock: jobs[source]["total"] = len(paths)
             futures = [scan_executor.submit(scan_one, path) for path in paths]
@@ -989,18 +992,59 @@ def start_scan(source, force=False):
             log.error("%s-Scan fehlgeschlagen: %s", source, error_summary(exc)); jobs[source]["error"] = str(exc); jobs[source]["state"] = "error"
     executor.submit(work)
 
-@app.route("/")
-def index():
-    error = None; rows = []; series = []
+def refresh_library_cache():
+    """Refresh Radarr/Sonarr data outside the request thread."""
+    rows = []
+    series = []
+    errors = []
+    radarr_ok = False
+    sonarr_ok = not (SONARR_URL and SONARR_API_KEY)
     try:
         rows = radarr_rows()
-        if any(row["pending"] for row in rows): start_scan("radarr")
-    except Exception as exc: error = str(exc)
+        radarr_ok = True
+    except Exception as exc:
+        errors.append(f"Radarr nicht erreichbar: {error_summary(exc)}")
     if SONARR_URL and SONARR_API_KEY:
         try:
             series = sonarr_groups()
-            if any(row["pending"] for group in series for row in group["episodes"]): start_scan("sonarr")
-        except Exception as exc: log.error("Sonarr nicht erreichbar: %s", error_summary(exc)); error = f"{error + ' | ' if error else ''}Sonarr nicht erreichbar"
+            sonarr_ok = True
+        except Exception as exc:
+            errors.append(f"Sonarr nicht erreichbar: {error_summary(exc)}")
+    with library_cache_lock:
+        # Keep the last good snapshot during a short service/DNS outage.
+        if not radarr_ok:
+            rows = library_cache["rows"]
+        if not sonarr_ok:
+            series = library_cache["series"]
+        library_cache.update({"rows": rows, "series": series, "updated_at": time.time(), "error": " | ".join(errors) or None, "ready": True})
+    if rows and any(row.get("pending") for row in rows):
+        start_scan("radarr", force=True, rows_snapshot=rows)
+    if series and any(row.get("pending") for group in series for row in group["episodes"]):
+        start_scan("sonarr", force=True, series_snapshot=series)
+    if rows or series:
+        start_scan("missing", force=True, rows_snapshot=rows, series_snapshot=series)
+    log.info("Bibliotheks-Sync abgeschlossen: %s Filme, %s Serien", len(rows), len(series))
+
+def background_library_sync():
+    """Keep library data and media metadata current without a browser tab."""
+    log.info("Hintergrund-Sync gestartet (Intervall: %ss)", SYNC_INTERVAL_SECONDS or "deaktiviert")
+    while True:
+        try:
+            refresh_library_cache()
+        except Exception as exc:
+            log.error("Hintergrund-Sync fehlgeschlagen: %s", error_summary(exc))
+        if not SYNC_INTERVAL_SECONDS:
+            return
+        time.sleep(SYNC_INTERVAL_SECONDS)
+
+threading.Thread(target=background_library_sync, name="library-sync", daemon=True).start()
+
+@app.route("/")
+def index():
+    with library_cache_lock:
+        rows = list(library_cache["rows"])
+        series = list(library_cache["series"])
+        error = library_cache["error"]
     missing_german_movies = [row for row in rows if is_german_review_candidate(row) and not has_german_track(row)]
     missing_german_series = []
     for group in series: