import cStringIO import hashlib import json import requests import tarfile import urlparse import uuid from django.conf import settings def publish_release(source, config, target): """ Publish a new release as a Docker image Given a source image and dictionary of last-mile configuration, create a target Docker image on the registry. For example publish_release('registry.local:5000/gabrtv/myapp', {'ENVVAR': 'values'}, 'registry.local:5000/gabrtv/myapp',) results in a new Docker image at 'registry.local:5000/gabrtv/myapp:v23' which contains the new configuration as ENV entries. """ try: src_image = source.rsplit(':', 1)[0] src_tag = source.rsplit(':', 1)[1] target_image = target.rsplit(':', 1)[0] target_tag = target.rsplit(':', 1)[1] image_id = _get_tag(src_image, src_tag) except RuntimeError: if src_tag == 'latest': # no image exists yet, so let's build one! _put_first_image(src_image) image_id = _get_tag(src_image, src_tag) else: raise image = _get_image(image_id) # construct the new image image['parent'] = image['id'] image['id'] = _new_id() image['config']['Env'] = _construct_env(image['config']['Env'], config) # update and tag the new image _commit(target_image, image, _empty_tar_archive(), target_tag) # registry access def _commit(repository_path, image, layer, tag): _put_image(image) cookies = _put_layer(image['id'], layer) _put_checksum(image, cookies) _put_tag(image['id'], repository_path, tag) # point latest to the new tag _put_tag(image['id'], repository_path, 'latest') def _put_first_image(repository_path): image = { 'id': _new_id(), 'parent': '', 'config': { 'Env': [] } } # tag as v0 in the registry _commit(repository_path, image, _empty_tar_archive(), 'v0') def _api_call(endpoint, data=None, headers={}, cookies=None, request_type='GET'): # FIXME: update API calls for docker 0.10.0+ base_headers = {'user-agent': 'docker/0.9.0'} r = None if len(headers) > 0: for header, value in headers.iteritems(): base_headers[header] = value if request_type == 'GET': r = requests.get(endpoint, headers=base_headers) elif request_type == 'PUT': r = requests.put(endpoint, data=data, headers=base_headers, cookies=cookies) else: raise AttributeError("request type not supported: {}".format(request_type)) return r def _get_tag(repository, tag): path = "/v1/repositories/{repository}/tags/{tag}".format(**locals()) url = urlparse.urljoin(settings.REGISTRY_URL, path) r = _api_call(url) if not r.status_code == 200: raise RuntimeError("GET Image Error ({}: {})".format(r.status_code, r.text)) return r.json() def _get_image(image_id): path = "/v1/images/{image_id}/json".format(**locals()) url = urlparse.urljoin(settings.REGISTRY_URL, path) r = _api_call(url) if not r.status_code == 200: raise RuntimeError("GET Image Error ({}: {})".format(r.status_code, r.text)) return r.json() def _put_image(image): path = "/v1/images/{id}/json".format(**image) url = urlparse.urljoin(settings.REGISTRY_URL, path) r = _api_call(url, data=json.dumps(image), request_type='PUT') if not r.status_code == 200: raise RuntimeError("PUT Image Error ({}: {})".format(r.status_code, r.text)) return r.json() def _put_layer(image_id, layer_fileobj): path = "/v1/images/{image_id}/layer".format(**locals()) url = urlparse.urljoin(settings.REGISTRY_URL, path) r = _api_call(url, data=layer_fileobj.read(), request_type='PUT') if not r.status_code == 200: raise RuntimeError("PUT Layer Error ({}: {})".format(r.status_code, r.text)) return r.cookies def _put_checksum(image, cookies): path = "/v1/images/{id}/checksum".format(**image) url = urlparse.urljoin(settings.REGISTRY_URL, path) tarsum = TarSum(json.dumps(image)).compute() headers = {'X-Docker-Checksum': tarsum} r = _api_call(url, headers=headers, cookies=cookies, request_type='PUT') if not r.status_code == 200: raise RuntimeError("PUT Checksum Error ({}: {})".format(r.status_code, r.text)) print r.json() def _put_tag(image_id, repository_path, tag): path = "/v1/repositories/{repository_path}/tags/{tag}".format(**locals()) url = urlparse.urljoin(settings.REGISTRY_URL, path) r = _api_call(url, data=json.dumps(image_id), request_type='PUT') if not r.status_code == 200: raise RuntimeError("PUT Tag Error ({}: {})".format(r.status_code, r.text)) print r.json() # utility functions def _construct_env(env, config): "Update current environment with latest config" new_env = [] # see if we need to update existing ENV vars for e in env: k, v = e.split('=', 1) if k in config: # update values defined by config v = config.pop(k) new_env.append("{}={}".format(k, v)) # add other config ENV items for k, v in config.items(): new_env.append("{}={}".format(k, v)) return new_env def _new_id(): "Return 64-char UUID for use as Image ID" return ''.join(uuid.uuid4().hex * 2) def _empty_tar_archive(): "Return an empty tar archive (in memory)" data = cStringIO.StringIO() tar = tarfile.open(mode="w", fileobj=data) tar.close() data.seek(0) return data # # Below adapted from https://github.com/dotcloud/docker-registry/blob/master/lib/checksums.py # def sha256_file(fp, data=None): h = hashlib.sha256(data or '') if not fp: return h.hexdigest() while True: buf = fp.read(4096) if not buf: break h.update(buf) return h.hexdigest() def sha256_string(s): return hashlib.sha256(s).hexdigest() class TarSum(object): def __init__(self, json_data): self.json_data = json_data self.hashes = [] self.header_fields = ('name', 'mode', 'uid', 'gid', 'size', 'mtime', 'type', 'linkname', 'uname', 'gname', 'devmajor', 'devminor') def append(self, member, tarobj): header = '' for field in self.header_fields: value = getattr(member, field) if field == 'type': field = 'typeflag' elif field == 'name': if member.isdir() and not value.endswith('/'): value += '/' header += '{0}{1}'.format(field, value) h = None try: if member.size > 0: f = tarobj.extractfile(member) h = sha256_file(f, header) else: h = sha256_string(header) except KeyError: h = sha256_string(header) self.hashes.append(h) def compute(self): self.hashes.sort() data = self.json_data + ''.join(self.hashes) tarsum = 'tarsum+sha256:{0}'.format(sha256_string(data)) return tarsum