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,

api/core/workflow/nodes/iteration/iteration_node.py

@@ -7,7 +7,7 @@ from datetime import UTC, datetime
 from queue import Empty, Queue
 from typing import TYPE_CHECKING, 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.variables import ArrayVariable, IntegerVariable, NoneVariable
@@ -37,6 +37,7 @@ from core.workflow.nodes.base import BaseNode
 from core.workflow.nodes.enums import NodeType
 from core.workflow.nodes.event import NodeEvent, RunCompletedEvent
 from core.workflow.nodes.iteration.entities import ErrorHandleMode, IterationNodeData
+from libs.flask_utils import preserve_flask_contexts
 
 from .exc import (
     InvalidIteratorValueError,
@@ -583,23 +584,8 @@ class IterationNode(BaseNode[IterationNodeData]):
         """
         run single iteration in parallel mode
         """
-        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():
-            # Restore user in new app context
-            if saved_user is not None:
-                from flask import g
-
-                g._login_user = saved_user
 
+        with preserve_flask_contexts(flask_app, context_vars=context):
             parallel_mode_run_id = uuid.uuid4().hex
             graph_engine_copy = graph_engine.create_copy()
             variable_pool_copy = graph_engine_copy.graph_runtime_state.variable_pool