feat: start node support json schema (#29053)

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

@@ -1,3 +1,8 @@
+from typing import Any
+
+from jsonschema import Draft7Validator, ValidationError
+
+from core.app.app_config.entities import VariableEntityType
 from core.workflow.constants import SYSTEM_VARIABLE_NODE_ID
 from core.workflow.enums import NodeExecutionType, NodeType, WorkflowNodeExecutionStatus
 from core.workflow.node_events import NodeRunResult
@@ -15,6 +20,7 @@ class StartNode(Node[StartNodeData]):
 
     def _run(self) -> NodeRunResult:
         node_inputs = dict(self.graph_runtime_state.variable_pool.user_inputs)
+        self._validate_and_normalize_json_object_inputs(node_inputs)
         system_inputs = self.graph_runtime_state.variable_pool.system_variables.to_dict()
 
         # TODO: System variables should be directly accessible, no need for special handling
@@ -24,3 +30,27 @@ class StartNode(Node[StartNodeData]):
         outputs = dict(node_inputs)
 
         return NodeRunResult(status=WorkflowNodeExecutionStatus.SUCCEEDED, inputs=node_inputs, outputs=outputs)
+
+    def _validate_and_normalize_json_object_inputs(self, node_inputs: dict[str, Any]) -> None:
+        for variable in self.node_data.variables:
+            if variable.type != VariableEntityType.JSON_OBJECT:
+                continue
+
+            key = variable.variable
+            value = node_inputs.get(key)
+
+            if value is None and variable.required:
+                raise ValueError(f"{key} is required in input form")
+
+            if not isinstance(value, dict):
+                raise ValueError(f"{key} must be a JSON object")
+
+            schema = variable.json_schema
+            if not schema:
+                continue
+
+            try:
+                Draft7Validator(schema).validate(value)
+            except ValidationError as e:
+                raise ValueError(f"JSON object for '{key}' does not match schema: {e.message}")
+            node_inputs[key] = value