potiuk commented on code in PR #54796: URL: https://github.com/apache/airflow/pull/54796#discussion_r2439301932
########## airflow-core/src/airflow/models/callback.py: ########## @@ -0,0 +1,207 @@ +# Licensed to the Apache Software Foundation (ASF) under one +# or more contributor license agreements. See the NOTICE file +# distributed with this work for additional information +# regarding copyright ownership. The ASF licenses this file +# to you under the Apache License, Version 2.0 (the +# "License"); you may not use this file except in compliance +# with the License. You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, +# software distributed under the License is distributed on an +# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +# KIND, either express or implied. See the License for the +# specific language governing permissions and limitations +# under the License. +from __future__ import annotations + +from enum import Enum +from importlib import import_module +from typing import TYPE_CHECKING, Any, Protocol, runtime_checkable + +import structlog +import uuid6 +from sqlalchemy import ForeignKey, Integer, String, Text +from sqlalchemy.orm import Mapped, relationship +from sqlalchemy_utils import UUIDType + +from airflow._shared.timezones import timezone +from airflow.models import Base +from airflow.utils.sqlalchemy import ExtendedJSON, UtcDateTime, mapped_column + +if TYPE_CHECKING: + from sqlalchemy.orm import Session + + from airflow.callbacks.callback_requests import CallbackRequest + from airflow.triggers.base import TriggerEvent + +log = structlog.get_logger(__name__) + + +class CallbackState(str, Enum): + """All possible states of callbacks.""" + + PENDING = "pending" + QUEUED = "queued" + RUNNING = "running" + SUCCESS = "success" + FAILED = "failed" + + +class CallbackType(str, Enum): + """ + Types of Callbacks. + + Used for figuring out what class to instantiate while deserialization. + """ + + TRIGGERER = "triggerer" + EXECUTOR = "executor" + DAG_PROCESSOR = "dag_processor" + + +class CallbackFetchMethod(str, Enum): + """Methods used to fetch callback at runtime.""" + + # For future use once Dag Processor callbacks (on_success_callback/on_failure_callback) get moved to executors + DAG_ATTRIBUTE = "dag_attribute" + + # For deadline callbacks since they import callbacks through the import path + IMPORT_PATH = "import_path" + + +class CallbackDefinitionProtocol(Protocol): + """Protocol for TaskSDK Callback definition.""" + + def serialize(self) -> dict[str, Any]: + """Serialize to a dictionary.""" + ... + + +@runtime_checkable +class ImportPathCallbackDefProtocol(CallbackDefinitionProtocol, Protocol): + """Protocol for callbacks that use the import path fetch method.""" + + path: str + kwargs: dict | None + + +@runtime_checkable +class ImportPathExecutorCallbackDefProtocol(ImportPathCallbackDefProtocol, Protocol): + """Protocol for callbacks that use the import path fetch method and have an executor attribute to specify the executor to run them on.""" + + executor: str | None + + +class Callback(Base): + """Base class for callbacks.""" + + __tablename__ = "callback" + + id: Mapped[str] = mapped_column(UUIDType(binary=False), primary_key=True, default=uuid6.uuid7) + + # This is used by SQLAlchemy to be able to deserialize DB rows to subclasses + __mapper_args__ = { + "polymorphic_identity": "callback", + "polymorphic_on": "type", + } + type: Mapped[str] = mapped_column(String(20), nullable=False) + + # Method used to fetch the callback, of type: CallbackFetchMethod + fetch_method: Mapped[str] = mapped_column(String(20), nullable=False) + + # Used by subclasses to store information about how to run the callback + data: Mapped[dict] = mapped_column(ExtendedJSON) + + # State of the Callback of type: CallbackState. Can be null for instances of DagProcessorCallback. + state: Mapped[str | None] = mapped_column(String(10)) + + # Return value of the callback if successful, otherwise exception details + output: Mapped[str | None] = mapped_column(Text, nullable=True) + + # Used for prioritization. Higher weight -> higher priority + priority_weight: Mapped[int] = mapped_column(Integer, nullable=False) + + # Creation time of the callback + created_at: Mapped[UtcDateTime] = mapped_column(UtcDateTime, default=timezone.utcnow, nullable=False) + + # Used for callbacks of type CallbackType.TRIGGERER + trigger_id: Mapped[int] = mapped_column(Integer, ForeignKey("trigger.id"), nullable=True) + trigger = relationship("Trigger", back_populates="callback", uselist=False) + + def __init__(self, priority_weight: int = 1): + self.state = CallbackState.PENDING + self.priority_weight = priority_weight + + def queue(self): + self.state = CallbackState.QUEUED + + @staticmethod + def create_from_sdk_def(callback_def: CallbackDefinitionProtocol) -> Callback: + # Cannot check actual type using isinstance() because that would require SDK import + match type(callback_def).__name__: + case "AsyncCallback": + if TYPE_CHECKING: + assert isinstance(callback_def, ImportPathCallbackDefProtocol) + return TriggererCallback(callback_def) + + case "SyncCallback": + if TYPE_CHECKING: + assert isinstance(callback_def, ImportPathExecutorCallbackDefProtocol) + return ExecutorCallback(callback_def, fetch_method=CallbackFetchMethod.IMPORT_PATH) + + case _: + raise ValueError(f"Cannot handle Callback of type {type(callback_def)}") + + +class TriggererCallback(Callback): + """Callbacks that run on the Triggerer (must be async).""" + + __mapper_args__ = {"polymorphic_identity": CallbackType.TRIGGERER} + + def __init__(self, callback_def: ImportPathCallbackDefProtocol, **kwargs): + super().__init__(**kwargs) + self.fetch_method = CallbackFetchMethod.IMPORT_PATH + self.data = callback_def.serialize() + + def queue(self): + # TODO: queue the trigger Review Comment: (IF so - I think we need to descrihbe what's missing and what are consequences if we do not complete it before merge) -- This is an automated message from the Apache Git Service. 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