airflow/__init__.py

#
# 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.
"""
Init setup.

Authentication is implemented using flask_login and different environments can
implement their own login mechanisms by providing an `airflow_login` module
in their PYTHONPATH. airflow_login should be based off the `airflow.www.login`

isort:skip_file
"""
from __future__ import annotations

__version__ = "2.7.0.dev0"

# flake8: noqa: F401

import os
import sys
from typing import Callable

if os.environ.get("_AIRFLOW_PATCH_GEVENT"):
    # If you are using gevents and start airflow webserver, you might want to run gevent monkeypatching
    # as one of the first thing when Airflow is started. This allows gevent to patch networking and other
    # system libraries to make them gevent-compatible before anything else patches them (for example boto)
    from gevent.monkey import patch_all

    patch_all()

# The configuration module initializes and validates the conf object as a side effect the first
# time it is imported. If it is not imported before importing the settings module, the conf
# object will then be initted/validated as a side effect of it being imported in settings,
# however this can cause issues since those modules are very tightly coupled and can
# very easily cause import cycles in the conf init/validate code (since downstream code from
# those functions likely import settings).
# configuration is therefore initted early here, simply by importing it.
from airflow import configuration
from airflow import settings

__all__ = ["__version__", "login", "DAG", "PY36", "PY37", "PY38", "PY39", "PY310", "XComArg"]

# Make `airflow` an namespace package, supporting installing
# airflow.providers.* in different locations (i.e. one in site, and one in user
# lib.)
__path__ = __import__("pkgutil").extend_path(__path__, __name__)  # type: ignore


# Perform side-effects unless someone has explicitly opted out before import
# WARNING: DO NOT USE THIS UNLESS YOU REALLY KNOW WHAT YOU'RE DOING.
if not os.environ.get("_AIRFLOW__AS_LIBRARY", None):
    settings.initialize()

login: Callable | None = None

PY36 = sys.version_info >= (3, 6)
PY37 = sys.version_info >= (3, 7)
PY38 = sys.version_info >= (3, 8)
PY39 = sys.version_info >= (3, 9)
PY310 = sys.version_info >= (3, 10)
PY311 = sys.version_info >= (3, 11)

# Things to lazy import in form {local_name: ('target_module', 'target_name')}
__lazy_imports: dict[str, tuple[str, str]] = {
    "DAG": (".models.dag", "DAG"),
    "Dataset": (".datasets", "Dataset"),
    "XComArg": (".models.xcom_arg", "XComArg"),
    "AirflowException": (".exceptions", "AirflowException"),
    "version": (".version", ""),
}


def __getattr__(name: str):
    # PEP-562: Lazy loaded attributes on python modules
    module_path, attr_name = __lazy_imports.get(name, ("", ""))
    if not module_path:
        raise AttributeError(f"module {__name__!r} has no attribute {name!r}")

    import importlib

    mod = importlib.import_module(module_path, __name__)
    if attr_name:
        val = getattr(mod, attr_name)
    else:
        val = mod

    # Store for next time
    globals()[name] = val
    return val


if not settings.LAZY_LOAD_PLUGINS:
    from airflow import plugins_manager

    plugins_manager.ensure_plugins_loaded()

if not settings.LAZY_LOAD_PROVIDERS:
    from airflow import providers_manager

    manager = providers_manager.ProvidersManager()
    manager.initialize_providers_list()
    manager.initialize_providers_hooks()
    manager.initialize_providers_extra_links()


# This is never executed, but tricks static analyzers (PyDev, PyCharm,)
# into knowing the types of these symbols, and what
# they contain.
STATICA_HACK = True
globals()["kcah_acitats"[::-1].upper()] = False
if STATICA_HACK:  # pragma: no cover
    from airflow.models.dag import DAG
    from airflow.models.xcom_arg import XComArg
    from airflow.exceptions import AirflowException
    from airflow.models.dataset import Dataset