feat: initial CamWatch service

Polls Frigate events API, extracts dominant vehicle color (KMeans), reads LPR plate from Frigate sub_label. Responsive dark UI with filter by plate/camera/date and auto-refresh. FastAPI + SQLite. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-06-02 14:10:05 +02:00
commit f6422b0e7e
9 changed files with 534 additions and 0 deletions
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+import os
+import time
+import logging
+import requests
+import shutil
+from database import event_exists, insert_event
+from analyzer import extract_dominant_color
+
+log = logging.getLogger("watcher")
+
+FRIGATE_URL = os.environ.get("FRIGATE_URL", "http://frigate:5000")
+SNAPSHOTS_DIR = os.environ.get("SNAPSHOTS_DIR", "/data/snapshots")
+POLL_INTERVAL = int(os.environ.get("POLL_INTERVAL", "30"))
+
+
+def fetch_new_events() -> list[dict]:
+    try:
+        resp = requests.get(
+            f"{FRIGATE_URL}/api/events",
+            params={"labels": "car", "has_snapshot": "1", "limit": "50"},
+            timeout=10
+        )
+        resp.raise_for_status()
+        return resp.json()
+    except Exception as e:
+        log.warning(f"Frigate fetch error: {e}")
+        return []
+
+
+def download_snapshot(event_id: str, dest_path: str) -> bool:
+    try:
+        resp = requests.get(
+            f"{FRIGATE_URL}/api/events/{event_id}/snapshot.jpg",
+            params={"bbox": "1", "crop": "1", "quality": "95"},
+            timeout=15, stream=True
+        )
+        resp.raise_for_status()
+        with open(dest_path, "wb") as f:
+            shutil.copyfileobj(resp.raw, f)
+        return True
+    except Exception as e:
+        log.warning(f"Snapshot download error for {event_id}: {e}")
+        return False
+
+
+def process_event(ev: dict):
+    event_id = ev.get("id", "")
+    if not event_id or event_exists(event_id):
+        return
+
+    camera = ev.get("camera", "unknown")
+    start_time = int(ev.get("start_time", time.time()))
+
+    # Plate from Frigate LPR
+    plate = None
+    data = ev.get("data", {})
+    if data.get("sub_label"):
+        plate = data["sub_label"]
+        if isinstance(plate, list):
+            plate = plate[0] if plate else None
+
+    # Download snapshot
+    snapshot_file = f"{event_id}.jpg"
+    snapshot_path = os.path.join(SNAPSHOTS_DIR, snapshot_file)
+    if not download_snapshot(event_id, snapshot_path):
+        return
+
+    # Extract color from vehicle bounding box
+    bbox = None
+    if ev.get("box"):
+        b = ev["box"]
+        bbox = {"x": b[0], "y": b[1], "width": b[2] - b[0], "height": b[3] - b[1]}
+    elif data.get("box"):
+        b = data["box"]
+        if len(b) == 4:
+            bbox = {"x": b[0], "y": b[1], "width": b[2] - b[0], "height": b[3] - b[1]}
+
+    hex_color, color_name = extract_dominant_color(snapshot_path, bbox)
+
+    insert_event(event_id, camera, start_time, f"snapshots/{snapshot_file}",
+                 plate, hex_color, color_name)
+    log.info(f"Processed event {event_id} | plate={plate} | color={color_name} | camera={camera}")
+
+
+def run_watcher():
+    log.info(f"Watcher started — polling Frigate every {POLL_INTERVAL}s")
+    while True:
+        events = fetch_new_events()
+        for ev in events:
+            try:
+                process_event(ev)
+            except Exception as e:
+                log.error(f"Error processing event: {e}")
+        time.sleep(POLL_INTERVAL)