FEAT: NEW WORKFLOW ENGINE (#3160)

Co-authored-by: Joel <iamjoel007@gmail.com>
Co-authored-by: Yeuoly <admin@srmxy.cn>
Co-authored-by: JzoNg <jzongcode@gmail.com>
Co-authored-by: StyleZhang <jasonapring2015@outlook.com>
Co-authored-by: jyong <jyong@dify.ai>
Co-authored-by: nite-knite <nkCoding@gmail.com>
Co-authored-by: jyong <718720800@qq.com>

api/core/workflow/nodes/start/entities.py

@@ -0,0 +1,9 @@
+from core.app.app_config.entities import VariableEntity
+from core.workflow.entities.base_node_data_entities import BaseNodeData
+
+
+class StartNodeData(BaseNodeData):
+    """
+    Start Node Data
+    """
+    variables: list[VariableEntity] = []

api/core/workflow/nodes/start/start_node.py

@@ -0,0 +1,84 @@
+from typing import cast
+
+from core.app.app_config.entities import VariableEntity
+from core.workflow.entities.base_node_data_entities import BaseNodeData
+from core.workflow.entities.node_entities import NodeRunResult, NodeType, SystemVariable
+from core.workflow.entities.variable_pool import VariablePool
+from core.workflow.nodes.base_node import BaseNode
+from core.workflow.nodes.start.entities import StartNodeData
+from models.workflow import WorkflowNodeExecutionStatus
+
+
+class StartNode(BaseNode):
+    _node_data_cls = StartNodeData
+    node_type = NodeType.START
+
+    def _run(self, variable_pool: VariablePool) -> NodeRunResult:
+        """
+        Run node
+        :param variable_pool: variable pool
+        :return:
+        """
+        node_data = self.node_data
+        node_data = cast(self._node_data_cls, node_data)
+        variables = node_data.variables
+
+        # Get cleaned inputs
+        cleaned_inputs = self._get_cleaned_inputs(variables, variable_pool.user_inputs)
+
+        for var in variable_pool.system_variables:
+            if var == SystemVariable.CONVERSATION:
+                continue
+
+            cleaned_inputs['sys.' + var.value] = variable_pool.system_variables[var]
+
+        return NodeRunResult(
+            status=WorkflowNodeExecutionStatus.SUCCEEDED,
+            inputs=cleaned_inputs,
+            outputs=cleaned_inputs
+        )
+
+    def _get_cleaned_inputs(self, variables: list[VariableEntity], user_inputs: dict):
+        if user_inputs is None:
+            user_inputs = {}
+
+        filtered_inputs = {}
+
+        for variable_config in variables:
+            variable = variable_config.variable
+
+            if variable not in user_inputs or not user_inputs[variable]:
+                if variable_config.required:
+                    raise ValueError(f"Input form variable {variable} is required")
+                else:
+                    filtered_inputs[variable] = variable_config.default if variable_config.default is not None else ""
+                    continue
+
+            value = user_inputs[variable]
+
+            if value:
+                if not isinstance(value, str):
+                    raise ValueError(f"{variable} in input form must be a string")
+
+            if variable_config.type == VariableEntity.Type.SELECT:
+                options = variable_config.options if variable_config.options is not None else []
+                if value not in options:
+                    raise ValueError(f"{variable} in input form must be one of the following: {options}")
+            else:
+                if variable_config.max_length is not None:
+                    max_length = variable_config.max_length
+                    if len(value) > max_length:
+                        raise ValueError(f'{variable} in input form must be less than {max_length} characters')
+
+            filtered_inputs[variable] = value.replace('\x00', '') if value else None
+
+        return filtered_inputs
+
+    @classmethod
+    def _extract_variable_selector_to_variable_mapping(cls, node_data: BaseNodeData) -> dict[str, list[str]]:
+        """
+        Extract variable selector to variable mapping
+        :param node_data: node data
+        :return:
+        """
+        return {}