Script to generate Dockerfile from container.

dockerfile-generator.py

#!/usr/bin/env python
# coding: utf-8

import docker
import jsondiff as jd
import re
import uuid


CLIENT = docker.from_env(timeout=600)

def gen_dockerfile(container_id):
    contents = []
    container = CLIENT.containers.get(container_id)
    # FROM
    contents.append("FROM {}".format(container.attrs.get("Config").get("Image")))
    # RUN
    contents.extend(get_run_command(container))
    # write Dockerfile
    with open("Dockerfile", "w", encoding="utf-8") as f:
        f.write("\n".join(contents))


def get_run_command(container):
    runs = []
    # get diff of images' history
    tmp_image_name = container.name + str(uuid.uuid4())
    tmp_image = container.commit(tmp_image_name)
    base_image = CLIENT.images.get(container.attrs.get("Config").get("Image"))
    commands = sorted(
        jd.diff(base_image.history(), tmp_image.history()).get(jd.insert), key=lambda x: x[1].get("Created")
    )
    for command in commands:
        created_by = command[1].get("CreatedBy")
        runs.append("RUN {}".format(created_by))
    # delete tmp image
    CLIENT.images.remove(tmp_image_name)
    return runs

if __name__ == "__main__":
    container_id = input(">> ")
    gen_dockerfile(container_id)