jason810496 commented on code in PR #51586: URL: https://github.com/apache/airflow/pull/51586#discussion_r2142863942
########## airflow-core/tests/unit/core/test_db_discovery.py: ########## @@ -0,0 +1,165 @@ +# 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 + +import contextlib +import logging +import os +import shutil +import socket +import time +from unittest.mock import patch + +import pytest +from sqlalchemy import text + +from airflow import settings +from airflow.utils import db_discovery +from airflow.utils.db_discovery import DbDiscoveryStatus + +from tests_common.test_utils.config import conf_vars + +log = logging.getLogger(__name__) + + +def dispose_connection_pool(): + """Dispose any cached sockets so that the next query will force a new connect.""" + settings.engine.dispose() + # Wait for SqlAlchemy. + time.sleep(0.5) + + +def make_db_test_call(): + """ + Create a session and execute a query. + + It will establish a new connection if there isn't one available. + New connections use DNS lookup. + """ + from airflow.utils.session import create_session + + with create_session() as session: + session.execute(text("SELECT 1")) + + +def assert_query_raises_exc(expected_error_msg: str, expected_status: str, expected_retry_num: int): + with pytest.raises(socket.gaierror, match=expected_error_msg): + make_db_test_call() + + assert len(db_discovery.db_health_status) == 2 + + assert db_discovery.db_health_status[0] == expected_status + assert db_discovery.db_retry_count == expected_retry_num + + +@pytest.mark.backend("postgres") +class TestDbDiscoveryIntegration: Review Comment: How about adding 2 fixtures: 1. for `db_discovery` module setup/ teardown, maybe called ( `prepare_db_discovery` ) Somehow like: ```python dispose_connection_pool() yield # Reset the values for the next tests. db_discovery.db_health_status = (DbDiscoveryStatus.OK, 0.0) db_discovery.db_retry_count = 0 ``` 2. another fixture is for dns resolution config Then all the case can use these fixture with `@pytest.mark.usefixtures` if needed. ########## airflow-core/src/airflow/utils/session.py: ########## @@ -38,6 +40,20 @@ def create_session(scoped: bool = True) -> Generator[SASession, None, None]: Session = getattr(settings, "NonScopedSession", None) if Session is None: raise RuntimeError("Session must be set before!") + + check_db_discovery = conf.getboolean("database", "check_db_discovery") + db_discovery_retries = conf.getint("database", "max_db_discovery_retries") + db_discovery_initial_wait = conf.getfloat("database", "db_discovery_initial_wait_time") + db_discovery_max_wait = conf.getfloat("database", "db_discovery_max_wait_time") + # If there is an exception, it will be raised + # in order to prevent the session from unnecessarily being created. + if check_db_discovery: + check_db_discovery_with_retries( + retry_num=db_discovery_retries, + initial_retry_wait=db_discovery_initial_wait, + max_retry_wait=db_discovery_max_wait, + ) Review Comment: nit: ```suggestion # If there is an exception, it will be raised # in order to prevent the session from unnecessarily being created. if conf.getboolean("database", "check_db_discovery"): check_db_discovery_with_retries( retry_num=conf.getint("database", "max_db_discovery_retries"), initial_retry_wait=conf.getfloat("database", "db_discovery_initial_wait_time"), max_retry_wait=conf.getfloat("database", "db_discovery_max_wait_time"), ) ``` ########## airflow-core/src/airflow/utils/db_discovery.py: ########## @@ -0,0 +1,127 @@ +# 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 + +import logging +import socket +import time + +import tenacity +from sqlalchemy.engine.url import make_url + +from airflow.configuration import conf + +logger = logging.getLogger(__name__) + + +class DbDiscoveryStatus: + """Enum with the return value for `check_db_discovery_if_needed()`.""" + + # The hostname resolves. + OK = "ok" + # There has been some temporary DNS lookup blip and the connection will probably recover. + # Causes: a dns timeout or a temporary network issue. + TEMPORARY_ERROR = "dns_temporary_failure" + # Unknown hostname or service, this is permanent and the connection can't be recovered. + # Causes: a cmd or config typo, a hostname that doesn't exist. + UNKNOWN_HOSTNAME = "unknown_hostname" + # Unknown hostname or service, this is permanent and the connection can't be recovered. + # Causes: Failed DNS server or config typo. + PERMANENT_ERROR = "dns_permanent_failure" + # Some other error. + UNKNOWN_ERROR = "unknown_error" + + +# db status - how long ago it was retrieved +db_health_status: tuple[str, float] = (DbDiscoveryStatus.OK, 0.0) + +# TODO: For now, this is used for testing +# but it can also be used to add stats. +db_retry_count: int = 0 + + +def _is_temporary_dns_error(ex: BaseException) -> bool: + return isinstance(ex, socket.gaierror) and ex.errno == socket.EAI_AGAIN Review Comment: How about make this util a lambda ? -- This is an automated message from the Apache Git Service. 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