Get comments history of image

docker-log.py

#!/usr/bin/env python

import json
import sys, subprocess

def get_history_ids(image_id):
    p = subprocess.Popen("docker history -q " + image_id,
                         stdout=subprocess.PIPE,
                         shell=True)
    (out, _err) = p.communicate()
    ids = out.split()
    return ids

def get_image_info(image_id):
    p = subprocess.Popen("docker inspect " + image_id,
                         stdout=subprocess.PIPE,
                         shell=True)
    (out, _err) = p.communicate()
    info = json.loads(out)[0]
    full_info = get_full_image_info(info, image_id)
    return full_info

def get_full_image_info(info, image_id_or_name):
    """Fill empty (in docker 1.3.1) Image field"""
    if image_id_or_name == info['Id'][:len(image_id_or_name)]:
        # id given, need to determine name
        image_id = image_id_or_name
        info['Image'] = get_image_name(image_id)
    else:
        # name given
        image_name = image_id_or_name
        info['Image'] = image_name
    return info

def get_image_name(image_id):
    p = subprocess.Popen("docker images | grep " + image_id,
                         stdout=subprocess.PIPE,
                         shell=True)
    (out, _err) = p.communicate()
    chunks = out.split()
    if chunks:
        return chunks[0] + ":" + chunks[1]
    else:
        return ''

def get_image_repo_tag(info):
    repo_tag = info['Image'].split(':')
    if repo_tag == ['']:
        return ['<none>','<none>']
    elif repo_tag == ['', '']:
        return ['<none>','<none>']
    else:
        return repo_tag

def print_table(table):
    col_width = [max(len(x) for x in col) for col in zip(*table)]
    for line in table:
        print "     ".join("{:{}}".format(x, col_width[i])
                           for i, x in enumerate(line))

if __name__ == '__main__':
    if len(sys.argv) > 1:
        image_id = sys.argv[1].strip()
        ids = get_history_ids(image_id)
        table = [['REPOSITORY', 'TAG', 'IMAGE ID', 'COMMENT']]
        for id in ids:
            info = get_image_info(id)
            [repo, tag] = get_image_repo_tag(info)
            comment = info['Comment']
            table.append([repo, tag, id, comment])
        print_table(table)
    else:
        print 'Usage: docker-log IMAGE'
        sys.exit(1)