 .. 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

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    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
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    under the License.

.. _write-logs-azure:

Writing logs to Azure Blob Storage
----------------------------------

Airflow can be configured to read and write task logs in Azure Blob Storage. It uses an existing
Airflow connection to read or write logs. If you don't have a connection properly setup,
this process will fail.

Follow the steps below to enable Azure Blob Storage logging:

#. Airflow's logging system requires a custom ``.py`` file to be located in the :envvar:`PYTHONPATH`, so that it's importable from Airflow. Start by creating a directory to store the config file, ``$AIRFLOW_HOME/config`` is recommended.
#. Create empty files called ``$AIRFLOW_HOME/config/log_config.py`` and ``$AIRFLOW_HOME/config/__init__.py``.
#. Copy the contents of ``airflow/config_templates/airflow_local_settings.py`` into the ``log_config.py`` file created in ``Step 2``.
#. Customize the following portions of the template:

    .. code-block:: ini

        # wasb buckets should start with "wasb" just to help Airflow select correct handler
        REMOTE_BASE_LOG_FOLDER = 'wasb-<whatever you want here>'

        # Rename DEFAULT_LOGGING_CONFIG to LOGGING CONFIG
        LOGGING_CONFIG = ...


#. Make sure a Azure Blob Storage (Wasb) connection hook has been defined in Airflow. The hook should have read and write access to the Azure Blob Storage bucket defined above in ``REMOTE_BASE_LOG_FOLDER``.

#. Update ``$AIRFLOW_HOME/airflow.cfg`` to contain:

    .. code-block:: ini

        [logging]
        remote_logging = True
        logging_config_class = log_config.LOGGING_CONFIG
        remote_log_conn_id = <name of the Azure Blob Storage connection>

#. Restart the Airflow webserver and scheduler, and trigger (or wait for) a new task execution.
#. Verify that logs are showing up for newly executed tasks in the bucket you have defined.