Running a Script in Docker
==========================

Here is a simple example of a wrapper script to call a docker image using the `docker python library <https://docker-py.readthedocs.io/en/stable/index.html>`_.

.. code-block:: python

    import argparse

    import docker

    parser = argparse.ArgumentParser(description="Docker test script")
    parser.add_argument("--phrase", type=str)

    if __name__ == "__main__":
        args = parser.parse_args()
        client = docker.from_env()
        print(client.containers.run("docker/whalesay", f"cowsay {args.phrase}").decode('utf-8'))

When running in this configuration, whatever environment the worker is running in must have access to docker.
Additionally, if you want assets generated by a dockerfile, you should mount the current working directory to
wherever the docker image outputs files to. For example, if a docker image output files to `/output`, the
above invocation would be changed to:

.. code-block:: python

    import argparse
    import os

    import docker
    from docker.types import Mount

    parser = argparse.ArgumentParser(description="Docker test script")

    if __name__ == "__main__":
        args = parser.parse_args()
        client = docker.from_env()
        # IMPORTANT #
        # This assumes we have a host directory for media storage (the MEDIA_ROOT setting) that has the same
        # path inside the container as the host (e.g. volume: /host/path:/host/path)
        wooey_data_dir = os.getcwd()
        print(
            client.containers.run(
                image="busybox",
                command=f"dd if=/dev/urandom of=/output/test.garbage bs=1M count=1",
                mounts=[Mount(target="/output", source=wooey_data_dir, type='bind')],
                ).decode(
                "utf-8"
            )
        )

If you are running Wooey inside Docker, then this becomes a bit more complicated as the data directory may
be on a mount point different on the host than inside the container. The following script shows how to handle
these scenarios:

.. code-block:: python

    import argparse
    import os

    import django
    django.setup()
    from django.conf import settings

    import docker
    from docker.types import Mount

    parser = argparse.ArgumentParser(description="Docker test script")

    if __name__ == "__main__":
        args = parser.parse_args()
        client = docker.from_env()
        # our volume is called `wooey_user_uploads`. If we had a NAS, then we could simplify this by ensuring the path
        # inside the container matches the path on the host -- in which case the above snippet is all that is needed.
        volume = client.volumes.get('wooey_user_uploads')
        volume_mount = volume.attrs['Mountpoint']
        current_dir = os.getcwd()
        wooey_data_dir = os.path.join(volume_mount.rstrip('/'), current_dir.replace(settings.MEDIA_ROOT, '').lstrip('/'))
        print(
            client.containers.run(
                image="busybox",
                command=f"dd if=/dev/urandom of=/output/test.garbage bs=1M count=1",
                mounts=[Mount(target="/output", source=wooey_data_dir, type='bind')],
                ).decode(
                "utf-8"
            )
        )