Reduce dashboard CPU: cache DB, suppress logs, add systemd service

- Suppress Flask request logs (werkzeug ERROR only)
- Cache SQLite connection with WAL + 8MB cache
- Increase poll_ms 500->1000, history refresh 30s->60s
- Show 'waiting for pipeline...' when /dev/shm empty
- Add chicken-dashboard.service for systemd auto-start

chicken-dashboard.service

@@ -0,0 +1,15 @@
+[Unit]
+Description=Chicken Counter Dashboard
+After=network.target
+
+[Service]
+Type=simple
+User=dsutanto
+WorkingDirectory=/media/jetson/DATA/.Codes/chicken-counting-sukawarna-det
+ExecStart=/usr/bin/python3 dashboard.py --port 8080 --db chicken_counts.db
+Restart=always
+RestartSec=5
+Environment=PYTHONUNBUFFERED=1
+
+[Install]
+WantedBy=multi-user.target

dashboard.py

@@ -9,20 +9,43 @@ from __future__ import annotations
 
 import argparse
 import json
+import logging
 import sqlite3
+import threading
 from pathlib import Path
 
 from flask import Flask, Response, jsonify, render_template, send_file
 
+# Suppress Flask request logs
+log = logging.getLogger("werkzeug")
+log.setLevel(logging.ERROR)
+
 DEFAULT_SHM_DIR = "/dev/shm"
 DEFAULT_PORT = 8080
 
 app = Flask(__name__)
 app.config["shm_dir"] = DEFAULT_SHM_DIR
-app.config["poll_ms"] = 500
+app.config["poll_ms"] = 1000
 app.config["run_date"] = ""
 app.config["db_path"] = ""
 
+_db_conn = None
+_db_lock = threading.Lock()
+
+
+def _get_db():
+    global _db_conn
+    db = app.config["db_path"]
+    if not db or not Path(db).exists():
+        return None
+    with _db_lock:
+        if _db_conn is None:
+            _db_conn = sqlite3.connect(db, check_same_thread=False)
+            _db_conn.row_factory = sqlite3.Row
+            _db_conn.execute("PRAGMA journal_mode=WAL")
+            _db_conn.execute("PRAGMA cache_size=-8000")
+        return _db_conn
+
 
 def _discover_cameras():
     shm = Path(app.config["shm_dir"])
@@ -88,7 +111,6 @@ def db_summary():
                ROUND(SUM(elapsed_seconds)/3600.0, 1) AS total_hours
         FROM batch_runs
     """).fetchone()
-    conn.close()
     return jsonify(dict(row))
 
 
@@ -107,7 +129,6 @@ def db_history():
         ORDER BY date DESC, location
         LIMIT 50
     """).fetchall()
-    conn.close()
     return jsonify([dict(r) for r in rows])
 
 
@@ -125,7 +146,6 @@ def db_date(date):
     total = conn.execute(
         "SELECT SUM(total_entered) AS total, ROUND(SUM(elapsed_seconds)/60.0,1) AS minutes "
         "FROM batch_runs WHERE date=?", (date,)).fetchone()
-    conn.close()
     return jsonify({"date": date, "total": dict(total), "cameras": [dict(r) for r in cameras]})
 
 
@@ -139,7 +159,6 @@ def db_camera(camera_id):
                ROUND(elapsed_seconds,1) AS elapsed_seconds, stopped_reason
         FROM batch_runs WHERE camera_id=? ORDER BY date DESC LIMIT 50
     """, (camera_id,)).fetchall()
-    conn.close()
     return jsonify([dict(r) for r in rows])
 
 
@@ -159,7 +178,6 @@ def db_location(location):
                ROUND(SUM(elapsed_seconds)/3600.0,1) AS hours
         FROM batch_runs WHERE location=?
     """, (location,)).fetchone()
-    conn.close()
     return jsonify({"location": location, "summary": dict(summary), "history": [dict(r) for r in history]})
 
 

templates/index.html

@@ -45,10 +45,12 @@ body{font-family:system-ui,monospace;background:#0f0f14;color:#e0e0e0;overflow:h
 </div>
 <div id="main">
 <div id="frame-area">
-<img id="frame-img" src="" alt="live stream">
+<canvas id="frame-canvas" style="display:none"></canvas>
-<div class="overlay">
+<img id="frame-img" src="" alt="live stream" style="display:none">
-<div class="tag live" id="cam-tag">CC1 &#x2022; RUNNING</div>
+<div id="waiting-msg" style="color:#555;font-size:16px;text-align:center">waiting for pipeline...</div>
-<div class="count" id="cam-count">--</div>
+<div class="overlay" id="frame-overlay" style="display:none">
+<div class="tag live" id="cam-tag"></div>
+<div class="count" id="cam-count"></div>
 </div>
 </div>
 <div id="sidebar">
@@ -76,7 +78,7 @@ function boot() {
     setInterval(poll, POLL_MS);
     setInterval(updateClock, 1000);
     loadHistory();
-    setInterval(loadHistory, 30000);
+    setInterval(loadHistory, 60000);
     updateClock();
 }
 
@@ -86,7 +88,9 @@ function loadCameras() {
         renderCamList();
         if (cameras.length && !activeCam) selectCam(cameras[0]);
         detectActive();
+        if (!cameras.length) showWaiting("no cameras detected");
     });
+    updateSidebar();
 }
 
 function detectActive() {
@@ -107,6 +111,9 @@ function detectActive() {
 
 function selectCam(id) {
     activeCam = id;
+    document.getElementById("waiting-msg").style.display = "none";
+    document.getElementById("frame-overlay").style.display = "block";
+    document.getElementById("frame-img").style.display = "block";
     renderCamList();
     refreshNow();
 }
@@ -141,6 +148,13 @@ function refreshNow() {
     document.getElementById("frame-img").src = "/shm/" + activeCam + "/frame.jpg?t=" + t;
 }
 
+function showWaiting(msg) {
+    document.getElementById("waiting-msg").textContent = msg;
+    document.getElementById("waiting-msg").style.display = "block";
+    document.getElementById("frame-overlay").style.display = "none";
+    document.getElementById("frame-img").style.display = "none";
+}
+
 function setOffline() {
     document.getElementById("cam-tag").textContent = activeCam + " \u2022 OFFLINE";
     document.getElementById("cam-tag").className = "tag off";