Fix cluster client uptime calculation

- Add connected_at timestamp to track when client first connected
- Calculate uptime from connection time instead of last seen time
- Update database schema and API to use proper uptime tracking

vidai/database.py

@@ -373,6 +373,7 @@ def init_db(conn) -> None:
                 gpu_info TEXT,
                 available_backends TEXT,
                 connected BOOLEAN DEFAULT 1,
+                connected_at TIMESTAMP NULL,
                 last_seen TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
                 created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
             ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci
@@ -389,6 +390,7 @@ def init_db(conn) -> None:
                 gpu_info TEXT,
                 available_backends TEXT,
                 connected BOOLEAN DEFAULT 1,
+                connected_at TIMESTAMP,
                 last_seen TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
                 created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
             )
@@ -1641,8 +1643,8 @@ def save_cluster_client(client_id: str, token: str, hostname: str, ip_address: s
     config = get_db_config()
     if config['type'] == 'mysql':
         cursor.execute('''
-            INSERT INTO cluster_clients (client_id, token, hostname, ip_address, weight, gpu_info, available_backends, connected, last_seen)
-            VALUES (?, ?, ?, ?, ?, ?, ?, 1, CURRENT_TIMESTAMP)
+            INSERT INTO cluster_clients (client_id, token, hostname, ip_address, weight, gpu_info, available_backends, connected, connected_at, last_seen)
+            VALUES (?, ?, ?, ?, ?, ?, ?, 1, CURRENT_TIMESTAMP, CURRENT_TIMESTAMP)
             ON DUPLICATE KEY UPDATE
                 hostname = VALUES(hostname),
                 ip_address = VALUES(ip_address),
@@ -1655,8 +1657,8 @@ def save_cluster_client(client_id: str, token: str, hostname: str, ip_address: s
     else:
         cursor.execute('''
             INSERT OR REPLACE INTO cluster_clients
-            (client_id, token, hostname, ip_address, weight, gpu_info, available_backends, connected, last_seen)
-            VALUES (?, ?, ?, ?, ?, ?, ?, 1, CURRENT_TIMESTAMP)
+            (client_id, token, hostname, ip_address, weight, gpu_info, available_backends, connected, connected_at, last_seen)
+            VALUES (?, ?, ?, ?, ?, ?, ?, 1, CURRENT_TIMESTAMP, CURRENT_TIMESTAMP)
         ''', (client_id, token, hostname, ip_address, weight, gpu_info_json, available_backends_json))
 
     conn.commit()

vidai/web.py

@@ -440,14 +440,14 @@ def api_cluster_nodes():
                     gpu_memory.extend([f"ROCm Device {i}: 16GB VRAM" for i in range(rocm_devices)])
                     total_memory += rocm_devices * 16
 
-            # Calculate uptime from last_seen
-            last_seen = client.get('last_seen')
-            if last_seen:
-                if isinstance(last_seen, str):
+            # Calculate uptime from connected_at (when client first connected)
+            connected_at = client.get('connected_at')
+            if connected_at:
+                if isinstance(connected_at, str):
                     # Parse timestamp string
                     import datetime
-                    last_seen = datetime.datetime.fromisoformat(last_seen.replace('Z', '+00:00')).timestamp()
-                uptime_seconds = current_time - last_seen
+                    connected_at = datetime.datetime.fromisoformat(connected_at.replace('Z', '+00:00')).timestamp()
+                uptime_seconds = current_time - connected_at
             else:
                 uptime_seconds = 0
 
@@ -470,7 +470,7 @@ def api_cluster_nodes():
                 'total_memory': total_memory,
                 'ip_address': client.get('ip_address', '127.0.0.1'),
                 'connected': client.get('connected', True),
-                'last_seen': last_seen or 0,
+                'last_seen': client.get('last_seen'),
                 'uptime_seconds': uptime_seconds,
                 'active_jobs': 0,  # Placeholder
                 'completed_jobs': 0,  # Placeholder