dify/api/services/trigger/workflow_plugin_trigger_service.py

from pydantic import BaseModel
from sqlalchemy import select
from sqlalchemy.orm import Session

from core.workflow.enums import NodeType
from extensions.ext_database import db
from extensions.ext_redis import redis_client
from models.model import App
from models.workflow import Workflow, WorkflowPluginTrigger


class WorkflowPluginTriggerService:
    """Service for managing workflow plugin triggers"""

    __PLUGIN_TRIGGER_NODE_CACHE_KEY__ = "plugin_trigger_nodes"
    MAX_PLUGIN_TRIGGER_NODES_PER_WORKFLOW = 5  # Maximum allowed plugin trigger nodes per workflow

    @classmethod
    def delete_plugin_trigger_by_subscription(
        cls,
        session: Session,
        tenant_id: str,
        subscription_id: str,
    ) -> None:
        """Delete a plugin trigger by tenant_id and subscription_id within an existing session

        Args:
            session: Database session
            tenant_id: The tenant ID
            subscription_id: The subscription ID

        Raises:
            NotFound: If plugin trigger not found
        """
        # Find plugin trigger using indexed columns
        plugin_trigger = session.scalar(
            select(WorkflowPluginTrigger).where(
                WorkflowPluginTrigger.tenant_id == tenant_id,
                WorkflowPluginTrigger.subscription_id == subscription_id,
            )
        )

        if not plugin_trigger:
            return

        session.delete(plugin_trigger)

    @classmethod
    def sync_plugin_trigger_relationships(cls, app: App, workflow: Workflow):
        """
        Sync plugin trigger relationships in DB.

        1. Check if the workflow has any plugin trigger nodes
        2. Fetch the nodes from DB, see if there were any plugin trigger records already
        3. Diff the nodes and the plugin trigger records, create/update/delete the records as needed

        Approach:
        Frequent DB operations may cause performance issues, using Redis to cache it instead.
        If any record exists, cache it.

        Limits:
        - Maximum 5 plugin trigger nodes per workflow
        """

        class Cache(BaseModel):
            """
            Cache model for plugin trigger nodes
            """

            record_id: str
            node_id: str
            provider_id: str
            event_name: str
            subscription_id: str

        # Walk nodes to find plugin triggers
        nodes_in_graph = []
        for node_id, node_config in workflow.walk_nodes(NodeType.TRIGGER_PLUGIN):
            # Extract plugin trigger configuration from node
            plugin_id = node_config.get("plugin_id", "")
            provider_id = node_config.get("provider_id", "")
            event_name = node_config.get("event_name", "")
            subscription_id = node_config.get("subscription_id", "")

            if not subscription_id:
                continue

            nodes_in_graph.append(
                {
                    "node_id": node_id,
                    "plugin_id": plugin_id,
                    "provider_id": provider_id,
                    "event_name": event_name,
                    "subscription_id": subscription_id,
                }
            )

        # Check plugin trigger node limit
        if len(nodes_in_graph) > cls.MAX_PLUGIN_TRIGGER_NODES_PER_WORKFLOW:
            raise ValueError(
                f"Workflow exceeds maximum plugin trigger node limit. "
                f"Found {len(nodes_in_graph)} plugin trigger nodes, "
                f"maximum allowed is {cls.MAX_PLUGIN_TRIGGER_NODES_PER_WORKFLOW}"
            )

        not_found_in_cache: list[dict] = []
        for node_info in nodes_in_graph:
            node_id = node_info["node_id"]
            # firstly check if the node exists in cache
            if not redis_client.get(f"{cls.__PLUGIN_TRIGGER_NODE_CACHE_KEY__}:{node_id}"):
                not_found_in_cache.append(node_info)
                continue

        with Session(db.engine) as session:
            try:
                # lock the concurrent plugin trigger creation
                redis_client.lock(f"{cls.__PLUGIN_TRIGGER_NODE_CACHE_KEY__}:apps:{app.id}:lock", timeout=10)
                # fetch the non-cached nodes from DB
                all_records = session.scalars(
                    select(WorkflowPluginTrigger).where(
                        WorkflowPluginTrigger.app_id == app.id,
                        WorkflowPluginTrigger.tenant_id == app.tenant_id,
                    )
                ).all()

                nodes_id_in_db = {node.node_id: node for node in all_records}
                nodes_id_in_graph = {node["node_id"] for node in nodes_in_graph}

                # get the nodes not found both in cache and DB
                nodes_not_found = [
                    node_info for node_info in not_found_in_cache if node_info["node_id"] not in nodes_id_in_db
                ]

                # create new plugin trigger records
                for node_info in nodes_not_found:
                    plugin_trigger = WorkflowPluginTrigger(
                        app_id=app.id,
                        tenant_id=app.tenant_id,
                        node_id=node_info["node_id"],
                        provider_id=node_info["provider_id"],
                        event_name=node_info["event_name"],
                        subscription_id=node_info["subscription_id"],
                    )
                    session.add(plugin_trigger)
                    session.flush()  # Get the ID for caching

                    cache = Cache(
                        record_id=plugin_trigger.id,
                        node_id=node_info["node_id"],
                        provider_id=node_info["provider_id"],
                        event_name=node_info["event_name"],
                        subscription_id=node_info["subscription_id"],
                    )
                    redis_client.set(
                        f"{cls.__PLUGIN_TRIGGER_NODE_CACHE_KEY__}:{node_info['node_id']}",
                        cache.model_dump_json(),
                        ex=60 * 60,
                    )
                session.commit()

                # Update existing records if subscription_id changed
                for node_info in nodes_in_graph:
                    node_id = node_info["node_id"]
                    if node_id in nodes_id_in_db:
                        existing_record = nodes_id_in_db[node_id]
                        if (
                            existing_record.subscription_id != node_info["subscription_id"]
                            or existing_record.provider_id != node_info["provider_id"]
                            or existing_record.event_name != node_info["event_name"]
                        ):
                            existing_record.subscription_id = node_info["subscription_id"]
                            existing_record.provider_id = node_info["provider_id"]
                            existing_record.event_name = node_info["event_name"]
                            session.add(existing_record)

                            # Update cache
                            cache = Cache(
                                record_id=existing_record.id,
                                node_id=node_id,
                                provider_id=node_info["provider_id"],
                                event_name=node_info["event_name"],
                                subscription_id=node_info["subscription_id"],
                            )
                            redis_client.set(
                                f"{cls.__PLUGIN_TRIGGER_NODE_CACHE_KEY__}:{node_id}",
                                cache.model_dump_json(),
                                ex=60 * 60,
                            )
                session.commit()

                # delete the nodes not found in the graph
                for node_id in nodes_id_in_db:
                    if node_id not in nodes_id_in_graph:
                        session.delete(nodes_id_in_db[node_id])
                        redis_client.delete(f"{cls.__PLUGIN_TRIGGER_NODE_CACHE_KEY__}:{node_id}")
                session.commit()
            except Exception:
                import logging

                logger = logging.getLogger(__name__)
                logger.exception("Failed to sync plugin trigger relationships for app %s", app.id)
                raise
            finally:
                redis_client.delete(f"{cls.__PLUGIN_TRIGGER_NODE_CACHE_KEY__}:apps:{app.id}:lock")