A small script to fetch latest pushed tags from docker hub.

latest_tags.py

#!/usr/bin/env python

# LICENSE: MIT
# (c) - Johannes Tegner

import json, sys, urllib.request

help_str = """Docker image tag fetcher.
Fetches latest tags from a public docker v2 registry api such as docker hub.

How to use:
python %cmd% image-name [registry-uri] [count]

Examples:
  python  %cmd% jitesoft/node-base https://registry.hub.docker.com/v2 3
  # Returns the 3 latest tags of jitesoft/node-base on docker hub.
  
  python %cmd% jitesoft/node-base
  # Will do as the above, as default registry is docker hub, and default count is 3.
"""

if len(sys.argv) == 1:
    print(help_str.replace('%cmd%', sys.argv[0]))
    sys.exit(1)

if len(sys.argv) < 2:
    sys.stderr.write('No image passed')
    sys.exit(5)

registry = 'https://registry.hub.docker.com/v2'
if len(sys.argv) >= 3:
    registry = str(sys.argv[2])


output_count = 3
if len(sys.argv) >= 4:
    output_count = int(sys.argv[3])

def get_json (uri):
    with urllib.request.urlopen(uri) as res:
        return json.loads(res.read())


image = sys.argv[1]
base_uri = 'https://registry.hub.docker.com/v2/repositories/'
image_uri = base_uri + image + '/tags'

# How many tags are there?
count_data = get_json(image_uri)
count = count_data['count']

# Now fetch all the tags!
full_data = get_json(image_uri + '?page_size=' + str(count))

# With the full data we find all the amd64 tags (as I know that there is _always_ an amd64 tag).
tag_set = full_data['results'] # This is an array.

unique_shas = {}

for tag in tag_set:
    for image in tag['images']:
        if image['architecture'] == 'amd64':
           unique_shas[ (image['digest']) ] = { "date": tag['tag_last_pushed'], "tags": [] }


for sha in unique_shas:
    # For each sha, get all images that have it...
    for tag in tag_set:
        for image in tag['images']:
            if image['architecture'] == 'amd64' and image['digest'] == sha:
                unique_shas[sha]['tags'].append(tag['name'])

all_tags = unique_shas.values()
all_tags = sorted(all_tags, key=lambda tag: tag['date'], reverse=True)
for tag in all_tags[0:output_count]:
    print(', '.join(tag['tags']))

Test it!

curl -SsL https://gist.githubusercontent.com/Johannestegner/af4754606b56fc7c5eeee21ee6717049/raw/latest_tags.py | python3 - jitesoft/node