Tool to remove unused volumes

rmvol.py

#!/usr/bin/env python
"""
Check all existing Docker containers for their mapped paths, and then purge any
zombie directories in docker's volumes directory which don't correspond to an
existing container.
FROM https://github.com/docker/docker/issues/6354#issuecomment-114688663
Modified by metalivedev to work with Docker 1.6.x
"""
import logging
import os
import sys
from shutil import rmtree

# pip install docker-py for this package
import docker


DOCKER_VOLUMES_DIR = "/var/lib/docker/vfs/dir"


def get_immediate_subdirectories(a_dir):
    return [os.path.join(a_dir, name) for name in os.listdir(a_dir)
            if os.path.isdir(os.path.join(a_dir, name))]


def main():
    logging.basicConfig(level=logging.INFO)
    # Specify the 1.6.x client version
    client = docker.Client(version="1.18")

    valid_dirs = []
    for container in client.containers(all=True):
        volumes = client.inspect_container(container['Id'])['Volumes']
        if not volumes:
            continue

        for _, real_path in volumes.iteritems():
            if real_path.startswith(DOCKER_VOLUMES_DIR):
                valid_dirs.append(real_path)

    all_dirs = get_immediate_subdirectories(DOCKER_VOLUMES_DIR)
    invalid_dirs = set(all_dirs).difference(valid_dirs)

    logging.info("Purging %s dangling Docker volumes out of %s total volumes found.",
                 len(invalid_dirs), len(all_dirs))
    for invalid_dir in invalid_dirs:
        logging.info("Purging directory: %s", invalid_dir)
        rmtree(invalid_dir)

    logging.info("All done.")


if __name__ == "__main__":
    sys.exit(main())