Add async support and update flag mechanism for shared storage

• Use asyncio.Lock  instead of thread lock for single process mode
• Add storage update notification system

lightrag/kg/shared_storage.py

@@ -1,7 +1,7 @@
 import os
 import sys
+import asyncio
 from multiprocessing.synchronize import Lock as ProcessLock
-from threading import Lock as ThreadLock
 from multiprocessing import Manager
 from typing import Any, Dict, Optional, Union
 
@@ -15,16 +15,18 @@ def direct_log(message, level="INFO"):
     print(f"{level}: {message}", file=sys.stderr, flush=True)
 
 
-LockType = Union[ProcessLock, ThreadLock]
+LockType = Union[ProcessLock, asyncio.Lock]
 
+is_multiprocess = None
+_workers = None
 _manager = None
 _initialized = None
-is_multiprocess = None
 _global_lock: Optional[LockType] = None
 
 # shared data for storage across processes
 _shared_dicts: Optional[Dict[str, Any]] = None
 _init_flags: Optional[Dict[str, bool]] = None  # namespace -> initialized
+_update_flags: Optional[Dict[str, bool]] = None # namespace -> updated
 
 
 def initialize_share_data(workers: int = 1):
@@ -47,12 +49,14 @@ def initialize_share_data(workers: int = 1):
     """
     global \
         _manager, \
+        _workers, \
         is_multiprocess, \
         is_multiprocess, \
         _global_lock, \
         _shared_dicts, \
         _init_flags, \
-        _initialized
+        _initialized, \
+        _update_flags
 
     # Check if already initialized
     if _initialized:
@@ -62,20 +66,23 @@ def initialize_share_data(workers: int = 1):
         return
 
     _manager = Manager()
+    _workers = workers
 
     if workers > 1:
         is_multiprocess = True
         _global_lock = _manager.Lock()
         _shared_dicts = _manager.dict()
         _init_flags = _manager.dict()
+        _update_flags = _manager.dict()
         direct_log(
             f"Process {os.getpid()} Shared-Data created for Multiple Process (workers={workers})"
         )
     else:
         is_multiprocess = False
-        _global_lock = ThreadLock()
+        _global_lock = asyncio.Lock()
         _shared_dicts = {}
         _init_flags = {}
+        _update_flags = {}
         direct_log(f"Process {os.getpid()} Shared-Data created for Single Process")
 
     # Mark as initialized
@@ -86,7 +93,6 @@ def initialize_share_data(workers: int = 1):
 
     # Create a shared list object for history_messages
     history_messages = _manager.list() if is_multiprocess else []
-
     pipeline_namespace.update(
         {
             "busy": False,  # Control concurrent processes
@@ -102,6 +108,58 @@ def initialize_share_data(workers: int = 1):
     )
 
 
+async def get_update_flags(namespace: str):
+    """
+    Create a updated flags of a specific namespace.
+    Caller must store the dict object locally and use it to determine when to update the storage.
+    """
+    global _update_flags
+    if _update_flags is None:
+        raise ValueError("Try to create namespace before Shared-Data is initialized")
+
+    if is_multiprocess:
+        with _global_lock:
+            if namespace not in _update_flags:
+                if _manager is not None:
+                    _update_flags[namespace] = _manager.list()
+                    direct_log(f"Process {os.getpid()} initialized updated flags for namespace: [{namespace}]")
+            
+            if _manager is not None:
+                new_update_flag = _manager.Value('b', False)
+                _update_flags[namespace].append(new_update_flag)
+                return new_update_flag
+    else:
+        async with _global_lock:
+            if namespace not in _update_flags:
+                _update_flags[namespace] = []
+                direct_log(f"Process {os.getpid()} initialized updated flags for namespace: [{namespace}]")
+            
+            new_update_flag = False
+            _update_flags[namespace].append(new_update_flag)
+            return new_update_flag
+
+async def set_update_flag(namespace: str):
+    """Set all update flag of namespace to indicate storage needs updating"""
+    global _update_flags
+    if _update_flags is None:
+        raise ValueError("Try to create namespace before Shared-Data is initialized")
+    
+    if is_multiprocess:
+        with _global_lock:
+            if namespace not in _update_flags:
+                raise ValueError(f"Namespace {namespace} not found in update flags")
+            # Update flags for multiprocess mode
+            for i in range(len(_update_flags[namespace])):
+                _update_flags[namespace][i].value = True
+    else:
+        async with _global_lock:
+            if namespace not in _update_flags:
+                raise ValueError(f"Namespace {namespace} not found in update flags")
+            # Update flags for single process mode
+            for i in range(len(_update_flags[namespace])):
+                _update_flags[namespace][i] = True
+
+
 def try_initialize_namespace(namespace: str) -> bool:
     """
     Try to initialize a namespace. Returns True if the current process gets initialization permission.
@@ -129,7 +187,7 @@ def get_storage_lock() -> LockType:
     return _global_lock
 
 
-def get_namespace_data(namespace: str) -> Dict[str, Any]:
+async def get_namespace_data(namespace: str) -> Dict[str, Any]:
     """get storage space for specific storage type(namespace)"""
     if _shared_dicts is None:
         direct_log(
@@ -138,12 +196,14 @@ def get_namespace_data(namespace: str) -> Dict[str, Any]:
         )
         raise ValueError("Shared dictionaries not initialized")
 
-    lock = get_storage_lock()
-    with lock:
+    if is_multiprocess:
+        with _global_lock:
             if namespace not in _shared_dicts:
-            if is_multiprocess and _manager is not None:
+                if _manager is not None:
                     _shared_dicts[namespace] = _manager.dict()
     else:
+        async with _global_lock:
+            if namespace not in _shared_dicts:
                 _shared_dicts[namespace] = {}
 
     return _shared_dicts[namespace]