dstandish commented on code in PR #28300: URL: https://github.com/apache/airflow/pull/28300#discussion_r1058624408
########## docs/apache-airflow/administration-and-deployment/public-airflow-interface.rst: ########## @@ -0,0 +1,87 @@ + .. 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. + +Public Interface of Airflow +=========================== + +The Public Interface of Apache Airflow is a set of programmatic interfaces that allow developers to interact +with and access certain features of the Apache Airflow system. This includes operations such as +creating and managing DAGs (directed acyclic graphs), managing tasks and their dependencies, +and extending Airflow capabilities by writing new executors, plugins, operators and providers. The +Public Interface can be useful for building custom tools and integrations with other systems, +and for automating certain aspects of the Airflow workflow. + +You can extend Airflow in three ways: + +* By writing new custom Python code (via Operators, Plugins, Provider) +* By using the `Stable REST API <stable-rest-api-ref>`_ (based on the OpenAPI specification) +* By using the `Airflow Command Line Interface (CLI) <cli-and-env-variables-ref.rst>`_ + +How can you extend Apache Airflow with custom Python Code? +========================================================== + +The Public Interface of Airflow consists of a number of different classes and packages that provide access +to the core features and functionality of the system. + +The classes and packages that may be considered as the Public Interface include: + +* The :class:`~airflow.DAG`, which provides a way to define and manage DAGs in Airflow. +* The :class:`~airflow.models.baseoperator.BaseOperator`, which provides a way write custom operators. +* The :class:`~airflow.hooks.base.BaseHook`, which provides a way write custom hooks. +* The :class:`~airflow.models.connection.Connection`, which provides access to external service credentials and configuration. +* The :class:`~airflow.models.variable.Variable`, which provides access to Airflow configuration variables. +* The :class:`~airflow.models.xcom.XCom` which are used to access to inter-task communication data. +* The :class:`~airflow.secrets.BaseSecretsBackend` which are used to define custom secret managers. +* The :class:`~airflow.plugins_manager.AirflowPlugin` which are used to define custom plugins. +* The :class:`~airflow.triggers.base.BaseTrigger`, which are used to implement custom Custom Deferrable Operators (based on ``asyncio``). +* The :class:`~airflow.decorators.base.TaskDecorator`, which provides a way write custom decorators. +* The :class:`~airflow.listeners.listener.ListenerManager` class which provides hooks that can be implemented to respond to DAG/Task lifecycle events. + +.. versionadded:: 2.5 + + Listener public interface has been added in version 2.5. + +* The :class:`~airflow.executors.base_executor.BaseExecutor` - the Executors are the components of Airflow + that are responsible for executing tasks. + +.. versionadded:: 2.6 + + There are a number of different executor implementations built-in Airflow, each with its own unique + characteristics and capabilities. Executor interface was available in earlier version of Airflow but + only as of version 2.6 executors are fully decoupled and Airflow does not rely on built-in set of executors. + You could have implemented (and succeeded) with implementing Executors before Airflow 2.6 and a number + of people succeeded in doing so, but there were some hard-coded behaviours that preferred in-built + executors, and custom executors could not provide full functionality that built-in executors had. + + +What is not part of the Public Interface of Apache Airflow? +=========================================================== + +Everything not mentioned in this document should be considered as non-Public Interface. Review Comment: This doesn't address providers, or how we can include "private" e.g. helper code in otherwise "public" modules / classes. Is it sufficient to include `:meta private:`? Or must we prefix with underscore? -- This is an automated message from the Apache Git Service. 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