How to copy a file from host to container using docker-py (docker SDK)

Question

I know, there is possible way how to copy file bidirectionally between host and docker container using docker cp and also it is possible to obtain file from running container using docker-py. But I am not able to figure out how (or if it is even possible) copy file from host to running container using docker-py. Do you guys have any experiences with such kind of problem? Is it possible to do or I have to execute command using python os.system. I would like to avoid this solution.

Answer 1

Something like this should work:

import os
import tarfile
import docker

client = docker.from_env()

def copy_to(src, dst):
    name, dst = dst.split(':')
    container = client.containers.get(name)

    os.chdir(os.path.dirname(src))
    srcname = os.path.basename(src)
    tar = tarfile.open(src + '.tar', mode='w')
    try:
        tar.add(srcname)
    finally:
        tar.close()

    data = open(src + '.tar', 'rb').read()
    container.put_archive(os.path.dirname(dst), data)

And then use it like:

copy_to('/local/foo.txt', 'my-container:/tmp/foo.txt')

Answer 2

Code snippet using memory BytesIO:

def copy_to_container(container: 'Container', src: str, dst_dir: str):
    """ src shall be an absolute path """
    stream = io.BytesIO()
    with tarfile.open(fileobj=stream, mode='w|') as tar, open(src, 'rb') as f:
        info = tar.gettarinfo(fileobj=f)
        info.name = os.path.basename(src)
        tar.addfile(info, f)

    container.put_archive(dst_dir, stream.getvalue())