Prepare for public release

docker-children

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+#!/usr/bin/python3
+#
+# usage: python3 docker_descendants.py <image_id> ...
+
+import sys
+from subprocess import check_output
+
+
+def main(images):
+    image_ids = set(images)
+    all_images = docker_images('--all', '--quiet')
+    all_links = parse_links(docker_links(all_images))
+    descendants = desc(image_ids, all_links)
+    pred = lambda s: lambda line: s[:12] in line
+    match = list(map(pred, descendants))
+    return filter(lambda i: any(s(i) for s in match), docker_images())
+
+
+def parse_links(lines):
+    parseid = lambda s: s.replace('sha256:', '')
+    for line in reversed(list(lines)):
+        yield list(map(parseid, line.split()))
+
+
+def desc(image_ids, links):
+    if links:
+        link, *tail = links
+        if len(link) > 1:
+            image_id, parent_id = link
+            checkid = lambda i: parent_id.startswith(i)
+            if any(map(checkid, image_ids)):
+                return desc(image_ids | {image_id}, tail)
+        return desc(image_ids, tail)
+    return image_ids
+
+
+def docker_links(images):
+    cmd = [ 'docker', 'inspect', '--format={{.Id}} {{.Parent}}']
+    return run(cmd + images)
+
+
+def docker_images(*args):
+    return run(('docker', 'images') + args)
+
+
+def run(cmd):
+    return check_output(cmd, universal_newlines=True).splitlines()
+
+
+if __name__ == '__main__':
+    print('\n'.join(main(sys.argv[1:])))