dify/api/services/workflow_service.py

import json
import time
from collections.abc import Sequence
from datetime import UTC, datetime
from typing import Optional, cast

from core.app.apps.advanced_chat.app_config_manager import AdvancedChatAppConfigManager
from core.app.apps.workflow.app_config_manager import WorkflowAppConfigManager
from core.model_runtime.utils.encoders import jsonable_encoder
from core.variables import Variable
from core.workflow.entities.node_entities import NodeRunResult
from core.workflow.errors import WorkflowNodeRunFailedError
from core.workflow.nodes import NodeType
from core.workflow.nodes.base.entities import BaseNodeData
from core.workflow.nodes.base.node import BaseNode
from core.workflow.nodes.enums import ErrorStrategy
from core.workflow.nodes.event import RunCompletedEvent
from core.workflow.nodes.event.event import SingleStepRetryEvent
from core.workflow.nodes.node_mapping import LATEST_VERSION, NODE_TYPE_CLASSES_MAPPING
from core.workflow.workflow_entry import WorkflowEntry
from events.app_event import app_draft_workflow_was_synced, app_published_workflow_was_updated
from extensions.ext_database import db
from models.account import Account
from models.enums import CreatedByRole
from models.model import App, AppMode
from models.workflow import (
    Workflow,
    WorkflowNodeExecution,
    WorkflowNodeExecutionStatus,
    WorkflowNodeExecutionTriggeredFrom,
    WorkflowType,
)
from services.errors.app import WorkflowHashNotEqualError
from services.workflow.workflow_converter import WorkflowConverter


class WorkflowService:
    """
    Workflow Service
    """

    def get_draft_workflow(self, app_model: App) -> Optional[Workflow]:
        """
        Get draft workflow
        """
        # fetch draft workflow by app_model
        workflow = (
            db.session.query(Workflow)
            .filter(
                Workflow.tenant_id == app_model.tenant_id, Workflow.app_id == app_model.id, Workflow.version == "draft"
            )
            .first()
        )

        # return draft workflow
        return workflow

    def get_published_workflow(self, app_model: App) -> Optional[Workflow]:
        """
        Get published workflow
        """

        if not app_model.workflow_id:
            return None

        # fetch published workflow by workflow_id
        workflow = (
            db.session.query(Workflow)
            .filter(
                Workflow.tenant_id == app_model.tenant_id,
                Workflow.app_id == app_model.id,
                Workflow.id == app_model.workflow_id,
            )
            .first()
        )

        return workflow

    def sync_draft_workflow(
        self,
        *,
        app_model: App,
        graph: dict,
        features: dict,
        unique_hash: Optional[str],
        account: Account,
        environment_variables: Sequence[Variable],
        conversation_variables: Sequence[Variable],
    ) -> Workflow:
        """
        Sync draft workflow
        :raises WorkflowHashNotEqualError
        """
        # fetch draft workflow by app_model
        workflow = self.get_draft_workflow(app_model=app_model)

        if workflow and workflow.unique_hash != unique_hash:
            raise WorkflowHashNotEqualError()

        # validate features structure
        self.validate_features_structure(app_model=app_model, features=features)

        # create draft workflow if not found
        if not workflow:
            workflow = Workflow(
                tenant_id=app_model.tenant_id,
                app_id=app_model.id,
                type=WorkflowType.from_app_mode(app_model.mode).value,
                version="draft",
                graph=json.dumps(graph),
                features=json.dumps(features),
                created_by=account.id,
                environment_variables=environment_variables,
                conversation_variables=conversation_variables,
            )
            db.session.add(workflow)
        # update draft workflow if found
        else:
            workflow.graph = json.dumps(graph)
            workflow.features = json.dumps(features)
            workflow.updated_by = account.id
            workflow.updated_at = datetime.now(UTC).replace(tzinfo=None)
            workflow.environment_variables = environment_variables
            workflow.conversation_variables = conversation_variables

        # commit db session changes
        db.session.commit()

        # trigger app workflow events
        app_draft_workflow_was_synced.send(app_model, synced_draft_workflow=workflow)

        # return draft workflow
        return workflow

    def publish_workflow(self, app_model: App, account: Account, draft_workflow: Optional[Workflow] = None) -> Workflow:
        """
        Publish workflow from draft

        :param app_model: App instance
        :param account: Account instance
        :param draft_workflow: Workflow instance
        """
        if not draft_workflow:
            # fetch draft workflow by app_model
            draft_workflow = self.get_draft_workflow(app_model=app_model)

        if not draft_workflow:
            raise ValueError("No valid workflow found.")

        # create new workflow
        workflow = Workflow(
            tenant_id=app_model.tenant_id,
            app_id=app_model.id,
            type=draft_workflow.type,
            version=str(datetime.now(UTC).replace(tzinfo=None)),
            graph=draft_workflow.graph,
            features=draft_workflow.features,
            created_by=account.id,
            environment_variables=draft_workflow.environment_variables,
            conversation_variables=draft_workflow.conversation_variables,
        )

        # commit db session changes
        db.session.add(workflow)
        db.session.flush()
        db.session.commit()

        app_model.workflow_id = workflow.id
        db.session.commit()

        # trigger app workflow events
        app_published_workflow_was_updated.send(app_model, published_workflow=workflow)

        # return new workflow
        return workflow

    def get_default_block_configs(self) -> list[dict]:
        """
        Get default block configs
        """
        # return default block config
        default_block_configs = []
        for node_class_mapping in NODE_TYPE_CLASSES_MAPPING.values():
            node_class = node_class_mapping[LATEST_VERSION]
            default_config = node_class.get_default_config()
            if default_config:
                default_block_configs.append(default_config)

        return default_block_configs

    def get_default_block_config(self, node_type: str, filters: Optional[dict] = None) -> Optional[dict]:
        """
        Get default config of node.
        :param node_type: node type
        :param filters: filter by node config parameters.
        :return:
        """
        node_type_enum = NodeType(node_type)

        # return default block config
        if node_type_enum not in NODE_TYPE_CLASSES_MAPPING:
            return None

        node_class = NODE_TYPE_CLASSES_MAPPING[node_type_enum][LATEST_VERSION]
        default_config = node_class.get_default_config(filters=filters)
        if not default_config:
            return None

        return default_config

    def run_draft_workflow_node(
        self, app_model: App, node_id: str, user_inputs: dict, account: Account
    ) -> WorkflowNodeExecution:
        """
        Run draft workflow node
        """
        # fetch draft workflow by app_model
        draft_workflow = self.get_draft_workflow(app_model=app_model)
        if not draft_workflow:
            raise ValueError("Workflow not initialized")

        # run draft workflow node
        start_at = time.perf_counter()
        retries = 0
        max_retries = 0
        should_retry = True
        retry_events = []

        try:
            while retries <= max_retries and should_retry:
                retry_start_at = time.perf_counter()
                node_instance, generator = WorkflowEntry.single_step_run(
                    workflow=draft_workflow,
                    node_id=node_id,
                    user_inputs=user_inputs,
                    user_id=account.id,
                )
                node_instance = cast(BaseNode[BaseNodeData], node_instance)
                max_retries = (
                    node_instance.node_data.retry_config.max_retries if node_instance.node_data.retry_config else 0
                )
                retry_interval = node_instance.node_data.retry_config.retry_interval_seconds
                node_run_result: NodeRunResult | None = None
                for event in generator:
                    if isinstance(event, RunCompletedEvent):
                        node_run_result = event.run_result

                        # sign output files
                        node_run_result.outputs = WorkflowEntry.handle_special_values(node_run_result.outputs)
                        break

                if not node_run_result:
                    raise ValueError("Node run failed with no run result")
                # single step debug mode error handling return
                if node_run_result.status == WorkflowNodeExecutionStatus.FAILED:
                    if (
                        retries == max_retries
                        and node_instance.node_type == NodeType.HTTP_REQUEST
                        and node_run_result.outputs
                        and not node_instance.should_continue_on_error
                    ):
                        node_run_result.status = WorkflowNodeExecutionStatus.SUCCEEDED
                        should_retry = False
                    else:
                        if node_instance.should_retry:
                            node_run_result.status = WorkflowNodeExecutionStatus.RETRY
                            retries += 1
                            node_run_result.retry_index = retries
                            retry_events.append(
                                SingleStepRetryEvent(
                                    inputs=WorkflowEntry.handle_special_values(node_run_result.inputs)
                                    if node_run_result.inputs
                                    else None,
                                    error=node_run_result.error,
                                    outputs=WorkflowEntry.handle_special_values(node_run_result.outputs)
                                    if node_run_result.outputs
                                    else None,
                                    retry_index=node_run_result.retry_index,
                                    elapsed_time=time.perf_counter() - retry_start_at,
                                    execution_metadata=WorkflowEntry.handle_special_values(node_run_result.metadata)
                                    if node_run_result.metadata
                                    else None,
                                )
                            )
                            time.sleep(retry_interval)
                        else:
                            should_retry = False
                    if node_instance.should_continue_on_error:
                        node_error_args = {
                            "status": WorkflowNodeExecutionStatus.EXCEPTION,
                            "error": node_run_result.error,
                            "inputs": node_run_result.inputs,
                            "metadata": {"error_strategy": node_instance.node_data.error_strategy},
                        }
                        if node_instance.node_data.error_strategy is ErrorStrategy.DEFAULT_VALUE:
                            node_run_result = NodeRunResult(
                                **node_error_args,
                                outputs={
                                    **node_instance.node_data.default_value_dict,
                                    "error_message": node_run_result.error,
                                    "error_type": node_run_result.error_type,
                                },
                            )
                        else:
                            node_run_result = NodeRunResult(
                                **node_error_args,
                                outputs={
                                    "error_message": node_run_result.error,
                                    "error_type": node_run_result.error_type,
                                },
                            )
                run_succeeded = node_run_result.status in (
                    WorkflowNodeExecutionStatus.SUCCEEDED,
                    WorkflowNodeExecutionStatus.EXCEPTION,
                )
                error = node_run_result.error if not run_succeeded else None
        except WorkflowNodeRunFailedError as e:
            node_instance = e.node_instance
            run_succeeded = False
            node_run_result = None
            error = e.error

        workflow_node_execution = WorkflowNodeExecution()
        workflow_node_execution.tenant_id = app_model.tenant_id
        workflow_node_execution.app_id = app_model.id
        workflow_node_execution.workflow_id = draft_workflow.id
        workflow_node_execution.triggered_from = WorkflowNodeExecutionTriggeredFrom.SINGLE_STEP.value
        workflow_node_execution.index = 1
        workflow_node_execution.node_id = node_id
        workflow_node_execution.node_type = node_instance.node_type
        workflow_node_execution.title = node_instance.node_data.title
        workflow_node_execution.elapsed_time = time.perf_counter() - start_at
        workflow_node_execution.created_by_role = CreatedByRole.ACCOUNT.value
        workflow_node_execution.created_by = account.id
        workflow_node_execution.created_at = datetime.now(UTC).replace(tzinfo=None)
        workflow_node_execution.finished_at = datetime.now(UTC).replace(tzinfo=None)
        if run_succeeded and node_run_result:
            # create workflow node execution
            inputs = WorkflowEntry.handle_special_values(node_run_result.inputs) if node_run_result.inputs else None
            process_data = (
                WorkflowEntry.handle_special_values(node_run_result.process_data)
                if node_run_result.process_data
                else None
            )
            outputs = WorkflowEntry.handle_special_values(node_run_result.outputs) if node_run_result.outputs else None

            workflow_node_execution.inputs = json.dumps(inputs)
            workflow_node_execution.process_data = json.dumps(process_data)
            workflow_node_execution.outputs = json.dumps(outputs)
            workflow_node_execution.execution_metadata = (
                json.dumps(jsonable_encoder(node_run_result.metadata)) if node_run_result.metadata else None
            )
            if node_run_result.status == WorkflowNodeExecutionStatus.SUCCEEDED:
                workflow_node_execution.status = WorkflowNodeExecutionStatus.SUCCEEDED.value
            elif node_run_result.status == WorkflowNodeExecutionStatus.EXCEPTION:
                workflow_node_execution.status = WorkflowNodeExecutionStatus.EXCEPTION.value
                workflow_node_execution.error = node_run_result.error
        else:
            # create workflow node execution
            workflow_node_execution.status = WorkflowNodeExecutionStatus.FAILED.value
            workflow_node_execution.error = error

        db.session.add(workflow_node_execution)
        db.session.commit()
        workflow_node_execution.retry_events = retry_events

        return workflow_node_execution

    def convert_to_workflow(self, app_model: App, account: Account, args: dict) -> App:
        """
        Basic mode of chatbot app(expert mode) to workflow
        Completion App to Workflow App

        :param app_model: App instance
        :param account: Account instance
        :param args: dict
        :return:
        """
        # chatbot convert to workflow mode
        workflow_converter = WorkflowConverter()

        if app_model.mode not in {AppMode.CHAT.value, AppMode.COMPLETION.value}:
            raise ValueError(f"Current App mode: {app_model.mode} is not supported convert to workflow.")

        # convert to workflow
        new_app = workflow_converter.convert_to_workflow(
            app_model=app_model,
            account=account,
            name=args.get("name", "Default Name"),
            icon_type=args.get("icon_type", "emoji"),
            icon=args.get("icon", "🤖"),
            icon_background=args.get("icon_background", "#FFEAD5"),
        )

        return new_app

    def validate_features_structure(self, app_model: App, features: dict) -> dict:
        if app_model.mode == AppMode.ADVANCED_CHAT.value:
            return AdvancedChatAppConfigManager.config_validate(
                tenant_id=app_model.tenant_id, config=features, only_structure_validate=True
            )
        elif app_model.mode == AppMode.WORKFLOW.value:
            return WorkflowAppConfigManager.config_validate(
                tenant_id=app_model.tenant_id, config=features, only_structure_validate=True
            )
        else:
            raise ValueError(f"Invalid app mode: {app_model.mode}")