refactor: move workflow package to dify_graph (#32844)

api/dify_graph/graph_engine/command_processing/command_handlers.py

@@ -0,0 +1,56 @@
+import logging
+from typing import final
+
+from typing_extensions import override
+
+from dify_graph.entities.pause_reason import SchedulingPause
+from dify_graph.runtime import VariablePool
+
+from ..domain.graph_execution import GraphExecution
+from ..entities.commands import AbortCommand, GraphEngineCommand, PauseCommand, UpdateVariablesCommand
+from .command_processor import CommandHandler
+
+logger = logging.getLogger(__name__)
+
+
+@final
+class AbortCommandHandler(CommandHandler):
+    @override
+    def handle(self, command: GraphEngineCommand, execution: GraphExecution) -> None:
+        assert isinstance(command, AbortCommand)
+        logger.debug("Aborting workflow %s: %s", execution.workflow_id, command.reason)
+        execution.abort(command.reason or "User requested abort")
+
+
+@final
+class PauseCommandHandler(CommandHandler):
+    @override
+    def handle(self, command: GraphEngineCommand, execution: GraphExecution) -> None:
+        assert isinstance(command, PauseCommand)
+        logger.debug("Pausing workflow %s: %s", execution.workflow_id, command.reason)
+        # Convert string reason to PauseReason if needed
+        reason = command.reason
+        pause_reason = SchedulingPause(message=reason)
+        execution.pause(pause_reason)
+
+
+@final
+class UpdateVariablesCommandHandler(CommandHandler):
+    def __init__(self, variable_pool: VariablePool) -> None:
+        self._variable_pool = variable_pool
+
+    @override
+    def handle(self, command: GraphEngineCommand, execution: GraphExecution) -> None:
+        assert isinstance(command, UpdateVariablesCommand)
+        for update in command.updates:
+            try:
+                variable = update.value
+                self._variable_pool.add(variable.selector, variable)
+                logger.debug("Updated variable %s for workflow %s", variable.selector, execution.workflow_id)
+            except ValueError as exc:
+                logger.warning(
+                    "Skipping invalid variable selector %s for workflow %s: %s",
+                    getattr(update.value, "selector", None),
+                    execution.workflow_id,
+                    exc,
+                )