Testing Plugin Manager State Isolation in Apache Airflow

apache/airflow

tests_common/test_utils/mock_plugins.py

            
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from __future__ import annotations

from contextlib import ExitStack, contextmanager
from unittest import mock

from airflow import __version__ as airflow_version

PLUGINS_MANAGER_NULLABLE_ATTRIBUTES = [
    "plugins",
    "macros_modules",
    "admin_views",
    "flask_blueprints",
    "fastapi_apps",
    "menu_links",
    "flask_appbuilder_views",
    "flask_appbuilder_menu_links",
    "global_operator_extra_links",
    "operator_extra_links",
    "registered_operator_link_classes",
    "timetable_classes",
    "hook_lineage_reader_classes",
]


PLUGINS_MANAGER_NULLABLE_ATTRIBUTES_V2_10 = [
    "plugins",
    "macros_modules",
    "admin_views",
    "flask_blueprints",
    "menu_links",
    "flask_appbuilder_views",
    "flask_appbuilder_menu_links",
    "global_operator_extra_links",
    "operator_extra_links",
    "registered_operator_link_classes",
    "timetable_classes",
    "hook_lineage_reader_classes",
]


@contextmanager
def mock_plugin_manager(plugins=None, **kwargs):
    """
    Protects the initial state and sets the default state for the airflow.plugins module.

    You can also overwrite variables by passing a keyword argument.

    airflow.plugins_manager uses many global variables. To avoid side effects, this decorator performs
    the following operations:

    1. saves variables state,
    2. set variables to default value,
    3. executes context code,
    4. restores the state of variables to the state from point 1.

    Use this context if you want your test to not have side effects in airflow.plugins_manager, and
    other tests do not affect the results of this test.
    """
    illegal_arguments = set(kwargs.keys()) - set(PLUGINS_MANAGER_NULLABLE_ATTRIBUTES) - {"import_errors"}
    if illegal_arguments:
        raise TypeError(
            f"TypeError: mock_plugin_manager got an unexpected keyword arguments: {illegal_arguments}"
        )
    # Handle plugins specially
    with ExitStack() as exit_stack:

        def mock_loaded_plugins():
            exit_stack.enter_context(mock.patch("airflow.plugins_manager.plugins", plugins or []))

        exit_stack.enter_context(
            mock.patch(
                "airflow.plugins_manager.load_plugins_from_plugin_directory", side_effect=mock_loaded_plugins
            )
        )

        if airflow_version <= "3":
            ATTR_TO_PATCH = PLUGINS_MANAGER_NULLABLE_ATTRIBUTES_V2_10
        else:
            ATTR_TO_PATCH = PLUGINS_MANAGER_NULLABLE_ATTRIBUTES

        for attr in ATTR_TO_PATCH:
            exit_stack.enter_context(mock.patch(f"airflow.plugins_manager.{attr}", kwargs.get(attr)))

        # Always start the block with an empty plugins, so ensure_plugins_loaded runs.
        exit_stack.enter_context(mock.patch("airflow.plugins_manager.plugins", None))
        exit_stack.enter_context(
            mock.patch("airflow.plugins_manager.import_errors", kwargs.get("import_errors", {}))
        )

        yield