feat: add a flask_context_manager. (#21061)

Signed-off-by: -LAN- <laipz8200@outlook.com>

api/core/workflow/graph_engine/graph_engine.py

@@ -9,7 +9,7 @@ from copy import copy, deepcopy
 from datetime import UTC, datetime
 from typing import Any, Optional, cast
 
-from flask import Flask, current_app, has_request_context
+from flask import Flask, current_app
 
 from configs import dify_config
 from core.app.apps.base_app_queue_manager import GenerateTaskStoppedError
@@ -53,6 +53,7 @@ from core.workflow.nodes.end.end_stream_processor import EndStreamProcessor
 from core.workflow.nodes.enums import ErrorStrategy, FailBranchSourceHandle
 from core.workflow.nodes.event import RunCompletedEvent, RunRetrieverResourceEvent, RunStreamChunkEvent
 from core.workflow.nodes.node_mapping import NODE_TYPE_CLASSES_MAPPING
+from libs.flask_utils import preserve_flask_contexts
 from models.enums import UserFrom
 from models.workflow import WorkflowType
 
@@ -537,24 +538,9 @@ class GraphEngine:
         """
         Run parallel nodes
         """
-        for var, val in context.items():
-            var.set(val)
 
-        # FIXME(-LAN-): Save current user before entering new app context
-        from flask import g
-
-        saved_user = None
-        if has_request_context() and hasattr(g, "_login_user"):
-            saved_user = g._login_user
-
-        with flask_app.app_context():
+        with preserve_flask_contexts(flask_app, context_vars=context):
             try:
-                # Restore user in new app context
-                if saved_user is not None:
-                    from flask import g
-
-                    g._login_user = saved_user
-
                 q.put(
                     ParallelBranchRunStartedEvent(
                         parallel_id=parallel_id,