Mostly convert the output of "docker inspect" into a Kubernetes ReplicationController

docker2rc.py

#! /usr/bin/env python
# -*- coding: utf-8 -*-
from __future__ import absolute_import, print_function, unicode_literals

import json
import re
import sys
import yaml


def main(argv):
    docker_fn = argv[1]
    replica_count = 1

    with open(docker_fn) as fh:
        #: :type: list[dict[unicode,object]]
        d_list = json.load(fh)
    if len(d_list) != 1:
        print('WARNING: I do not yet do anything intelligent with multiple Docker inspect entries',
              file=sys.stderr)
    d = d_list[0]
    #: :type: unicode
    container_name = d['Name']
    name = re.sub(r'/?(.*)-\d+$', r'\1', container_name)
    #: :type: dict[unicode, object|unicode|dict]
    d_config = d['Config']
    docker_image = d_config['Image']
    version = re.sub(r'.*?:([0-9\.]+)$', r'\1', docker_image)

    def env_to_dict(e_str):
        #: :type: list[unicode]
        parts = e_str.split('=')
        assert len(parts) == 2, 'Unexpected ENV value: <<{0}>>'.format(e_str)
        return {
            "name":  re.sub(r'-', '_', parts[0]),
            "value":  parts[1],
        }

    def ports_to_port(exposed_ports_dict):
        """:type exposed_ports_dict: dict[unicode, dict]"""
        #: :type: list[dict[unicode, object]]
        results = []
        #: :type: list[int]
        the_ports = []
        for k in exposed_ports_dict.keys():
            parts = k.split('/')
            assert len(parts) == 2, 'Unexpected "ExposedPorts" value <<{0}>>'.format(k)
            the_ports.append(int(parts[0]))
        the_ports.sort()
        # we're counting on the "business" port being the lower of the two
        for idx, p in enumerate(the_ports):
            results.append({
                "name": "http" if idx == 0 else "management",
                "containerPort": p,
            })
        return results

    container_ports = ports_to_port(d_config['ExposedPorts'])
    rc = {
        "apiVersion": "v1",
        "kind": "ReplicationController",
        "metadata": {
            "name": name,
            "labels": {
                "app": name,
                "version": version,
            }
        },
        "spec": {
            "replicas": replica_count,
            "template": {
                "metadata": {
                    "labels": {
                        "app": name,
                        "version": version,
                    },
                },
                "spec": {
                    "containers": [
                        {
                            "name": name,
                            "image": docker_image,
                            "env": [env_to_dict(it) for it in d_config['Env']],
                            "ports": container_ports,
                            "readinessProbe": {
                                "httpGet": {
                                    "scheme": "HTTP",
                                    "port": [it['containerPort'] for it in container_ports
                                             if it['name'] == 'management'][0],
                                    "path": "/health",
                                }
                            },
                            "resources": {
                                "limits": {
                                    "memory": '1536Mi',
                                }
                            },
                        },
                    ]
                }
            }
        }
    }
    yaml.safe_dump(rc, sys.stdout)

if __name__ == '__main__':
    main(sys.argv)