Environment  Variables and Datacube_OWS
=======================================

The behaviour of datacube_ows can be modified by a number of environment
variables.

.. contents:: Table of Contents

Datacube_ows configuration
--------------------------

The location of the `datacube configuration object <configuration.rst>`_
is set via the ``$DATACUBE_OWS_CFG`` environment variable as described
`here <configuration.rst>`_. To enable the retrieval of a json configuration file from AWS S3,
the ``$DATACUBE_OWS_CFG_ALLOW_S3`` environment variable needs to be set to ``YES``.

Open DataCube Database Connection
---------------------------------

The preferred method of configuring the ODC database is with the ``$DB_*``
environment variables:

DB_HOSTNAME:
    The hostname or IP address of the database server. Defaults to ``localhost``.

DB_PORT:
    The port number of the database server. Defaults to ``5432``.

DB_DATABASE:
    The database name.

DB_USERNAME:
    The database user to connect as.

DB_PASSWORD:
    The database password.

Other valid methods for configuring an OpenDatacube instance (e.g. a ``.datacube.conf`` file)
should also work.

Configuring AWS Access
----------------------

Environment variables for AWS access are mostly read through the boto3 library - please
refer to their documentation for details.

Of particular note are:

AWS_DEFAULT_REGION:
    S3 access by datacube_ows will be disabled unless this is set.

AWS_NO_SIGN_REQUEST:
    S3 access will be unsigned if this environment variable is set
    to "y", "t", "yes", "true" or "1".

    If requests are signed then you will also need to ensure that
    boto3 has access to appropriate AWS credentials - typically
    the ``$AWS_ACCESS_KEY_ID`` and ``$AWS_SECRET_ACCESS_KEY`` environment
    variables.

    N.B. Signed requests are the default behaviour - explicitly
    set ``$AWS_NO_SIGN_REQUEST`` to 'yes' to use unsigned request.
    The default behaviour for this variable changed in version 1.8.17.

AWS_REQUEST_PAYER:
    Set to "requester" if accessing requester-pays S3 buckets.
    Default behaviour is to prevent access to requester-pays buckets.

AWS_S3_ENDPOINT:
    Set to the DNS host name of the S3 endpoint.  Required for accessing
    non-Amazon implementations of the S3 protocol, and for some newer AWS regions
    (e.g. Africa).

Configuring Flask
-----------------

Datacube_ows uses the
`Flask web application framework <https://palletsprojects.com/p/flask>`_
which can read from several environment variables, most notably:

FLASK_APP:
      Should point to the ``datacube_ows/ogc.py`` file in your deployment.

The ``$FLASK_ENV`` environment variable also has a significant
effect on the way datacube_ows runs. Refer to the Flask documentation
for further details.

Dev-ops Tools
-------------

The following deployment tools are configured via environment variables:

SENTRY_DSN:
    The `Sentry application monitoring and error tracking system`_
    system is activated and configured with the ``$SENTRY_DSN``
    environment variables.

prometheus_multiproc_dir:
    The `Prometheus event monitoring system <https://prometheus.io>`_ is activated by
    setting this lower case environment variable.

Dev Tools
---------

PYDEV_DEBUG:
    If set to anything other than "n", "f", "no" or "false" (case insensitive), activates PyDev remote debugging.

DEFER_CFG_PARSE:
    If set, the configuration file is not read and parsed at startup.  This
    is mostly useful for creating test fixtures.

Docker and Docker-compose
-------------------------

The provided ``Dockerfile`` and ``docker-compose.yaml`` read additional
environment variables at build time.  Please refer to the `README <https://datacube-ows.readthedocs.io/en/latest/readme.html>`_
for further details.

environment variables exclusive for docker-compose
--------------------------------------------------
OWS_CFG_DIR:
    path to a folder containing ows config files anywhere on the local machine

OWS_CFG_MOUNT_DIR:
    path the OWS_CFG_FOLDER will mount to inside docker container

PYTHONPATH:
    PYTHONPATH to ows config file