add Leader election

api/controllers/console/app/online_user.py

@@ -70,10 +70,17 @@ def handle_user_connect(sid, data):
     redis_client.hset(f"workflow_online_users:{workflow_id}", user_id, json.dumps(user_info))
     redis_client.set(f"ws_sid_map:{sid}", json.dumps({"workflow_id": workflow_id, "user_id": user_id}))
 
+    # Leader election: first user becomes the leader
+    leader_id = get_or_set_leader(workflow_id, user_id)
+    is_leader = leader_id == user_id
+
     sio.enter_room(sid, workflow_id)
     broadcast_online_users(workflow_id)
+    
+    # Notify user of their status
+    sio.emit("status", {"isLeader": is_leader}, room=sid)
 
-    return {"msg": "connected", "user_id": user_id, "sid": sid}
+    return {"msg": "connected", "user_id": user_id, "sid": sid, "isLeader": is_leader}
 
 
 @sio.on("disconnect")
@@ -89,9 +96,83 @@ def handle_disconnect(sid):
         redis_client.hdel(f"workflow_online_users:{workflow_id}", user_id)
         redis_client.delete(f"ws_sid_map:{sid}")
 
+        # Handle leader re-election if the leader disconnected
+        handle_leader_disconnect(workflow_id, user_id)
+        
         broadcast_online_users(workflow_id)
 
 
+def get_or_set_leader(workflow_id, user_id):
+    """
+    Get current leader or set the user as leader if no leader exists.
+    Returns the leader user_id.
+    """
+    leader_key = f"workflow_leader:{workflow_id}"
+    current_leader = redis_client.get(leader_key)
+    
+    if not current_leader:
+        # No leader exists, make this user the leader
+        redis_client.set(leader_key, user_id, ex=3600)  # Expire in 1 hour
+        return user_id
+    
+    return current_leader.decode('utf-8') if isinstance(current_leader, bytes) else current_leader
+
+
+def handle_leader_disconnect(workflow_id, disconnected_user_id):
+    """
+    Handle leader re-election when a user disconnects.
+    """
+    leader_key = f"workflow_leader:{workflow_id}"
+    current_leader = redis_client.get(leader_key)
+    
+    if current_leader:
+        current_leader = current_leader.decode('utf-8') if isinstance(current_leader, bytes) else current_leader
+        
+        if current_leader == disconnected_user_id:
+            # Leader disconnected, elect a new leader
+            users_json = redis_client.hgetall(f"workflow_online_users:{workflow_id}")
+            
+            if users_json:
+                # Get the first remaining user as new leader
+                new_leader_id = list(users_json.keys())[0]
+                if isinstance(new_leader_id, bytes):
+                    new_leader_id = new_leader_id.decode('utf-8')
+                    
+                redis_client.set(leader_key, new_leader_id, ex=3600)
+                
+                # Notify all users about the new leader
+                broadcast_leader_change(workflow_id, new_leader_id)
+            else:
+                # No users left, remove leader
+                redis_client.delete(leader_key)
+
+
+def broadcast_leader_change(workflow_id, new_leader_id):
+    """
+    Broadcast leader change to all users in the workflow.
+    """
+    users_json = redis_client.hgetall(f"workflow_online_users:{workflow_id}")
+    
+    for user_id, user_info_json in users_json.items():
+        try:
+            user_info = json.loads(user_info_json)
+            user_sid = user_info.get("sid")
+            if user_sid:
+                is_leader = (user_id.decode('utf-8') if isinstance(user_id, bytes) else user_id) == new_leader_id
+                sio.emit("status", {"isLeader": is_leader}, room=user_sid)
+        except Exception:
+            continue
+
+
+def get_current_leader(workflow_id):
+    """
+    Get the current leader for a workflow.
+    """
+    leader_key = f"workflow_leader:{workflow_id}"
+    leader = redis_client.get(leader_key)
+    return leader.decode('utf-8') if leader and isinstance(leader, bytes) else leader
+
+
 def broadcast_online_users(workflow_id):
     """
     broadcast online users to the workflow room
@@ -103,7 +184,15 @@ def broadcast_online_users(workflow_id):
             users.append(json.loads(user_info_json))
         except Exception:
             continue
-    sio.emit("online_users", {"workflow_id": workflow_id, "users": users}, room=workflow_id)
+    
+    # Get current leader
+    leader_id = get_current_leader(workflow_id)
+    
+    sio.emit("online_users", {
+        "workflow_id": workflow_id, 
+        "users": users,
+        "leader": leader_id
+    }, room=workflow_id)
 
 
 @sio.on("collaboration_event")