Implement support for registry integration tests via py.test

This change implements support for registry integration tests using the new py.test-based live server test fixture. We can now parametrize the protocols we use (in prep for V2_2), and it makes the code *much* cleaner and less hacky.

Note that moving the vast majority of the tests over from the existing impl will come as a followup PR

test/registry/protocol_v1.py

@@ -0,0 +1,144 @@
+import json
+
+from cStringIO import StringIO
+from enum import Enum, unique
+
+from digest.checksums import compute_simple
+from test.registry.protocols import (RegistryProtocol, Failures, ProtocolOptions, PushResult,
+                                     PullResult)
+
+@unique
+class V1ProtocolSteps(Enum):
+  """ Defines the various steps of the protocol, for matching failures. """
+  PUT_IMAGES = 'put-images'
+  GET_IMAGES = 'get-images'
+
+
+class V1Protocol(RegistryProtocol):
+  FAILURE_CODES = {
+    V1ProtocolSteps.PUT_IMAGES: {
+      Failures.UNAUTHENTICATED: 401,
+      Failures.UNAUTHORIZED: 403,
+    },
+    V1ProtocolSteps.GET_IMAGES: {
+      Failures.UNAUTHENTICATED: 403,
+      Failures.UNAUTHORIZED: 403,
+    },
+  }
+
+  def __init__(self, jwk):
+    pass
+
+  def _auth_for_credentials(self, credentials):
+    if credentials is None:
+      return None
+
+    return credentials
+
+  def ping(self, session):
+    assert session.get('/v1/_ping').status_code == 200
+
+  def pull(self, session, namespace, repo_name, tag_names, images, credentials=None,
+           expected_failure=None, options=None):
+    options = options or ProtocolOptions()
+    auth = self._auth_for_credentials(credentials)
+    tag_names = [tag_names] if isinstance(tag_names, str) else tag_names
+    prefix = '/v1/repositories/%s/%s/' % (namespace, repo_name)
+
+    # Ping!
+    self.ping(session)
+
+    # GET /v1/repositories/{namespace}/{repository}/images
+    result = self.conduct(session, 'GET', prefix + 'images', auth=auth,
+                          expected_status=(200, expected_failure, V1ProtocolSteps.GET_IMAGES))
+    if expected_failure is not None:
+      return
+
+    # GET /v1/repositories/{namespace}/{repository}/tags
+    tags_result = self.conduct(session, 'GET', prefix + 'tags', auth=auth).json()
+    assert len(tags_result.values()) == len(tag_names)
+
+    tag_image_id = tags_result['latest']
+    if not options.munge_shas:
+      # Ensure we have a matching image ID.
+      known_ids = {image.id for image in images}
+      assert tag_image_id in known_ids
+
+    # Retrieve the ancestry of the tagged image.
+    image_prefix = '/v1/images/%s/' % tag_image_id
+    ancestors = self.conduct(session, 'GET', image_prefix + 'ancestry', auth=auth).json()
+
+    assert len(ancestors) == len(images)
+    for index, image_id in enumerate(reversed(ancestors)):
+      # /v1/images/{imageID}/{ancestry, json, layer}
+      image_prefix = '/v1/images/%s/' % image_id
+      self.conduct(session, 'GET', image_prefix + 'ancestry', auth=auth)
+
+      result = self.conduct(session, 'GET', image_prefix + 'json', auth=auth)
+      assert result.json()['id'] == image_id
+
+      # Ensure we can HEAD the image layer.
+      self.conduct(session, 'HEAD', image_prefix + 'layer', auth=auth)
+
+      # And retrieve the layer data.
+      result = self.conduct(session, 'GET', image_prefix + 'layer', auth=auth)
+      assert result.content == images[index].bytes
+
+    return PullResult(manifests=None)
+
+  def push(self, session, namespace, repo_name, tag_names, images, credentials=None,
+           expected_failure=None, options=None):
+    auth = self._auth_for_credentials(credentials)
+    tag_names = [tag_names] if isinstance(tag_names, str) else tag_names
+
+    # Ping!
+    self.ping(session)
+
+    # PUT /v1/repositories/{namespace}/{repository}/
+    result = self.conduct(session, 'PUT', '/v1/repositories/%s/%s/' % (namespace, repo_name),
+                          expected_status=(201, expected_failure, V1ProtocolSteps.PUT_IMAGES),
+                          json_data={},
+                          auth=auth)
+
+    if expected_failure is not None:
+      return
+
+    headers = {}
+    headers['Authorization'] = 'token ' + result.headers['www-authenticate']
+
+    for image in images:
+      # PUT /v1/images/{imageID}/json
+      image_json_data = {'id': image.id}
+      if image.size is not None:
+        image_json_data['Size'] = image.size
+
+      if image.parent_id is not None:
+        image_json_data['parent'] = image.parent_id
+
+      self.conduct(session, 'PUT', '/v1/images/%s/json' % image.id,
+                   json_data=image_json_data, headers=headers)
+
+      # PUT /v1/images/{imageID}/layer
+      self.conduct(session, 'PUT', '/v1/images/%s/layer' % image.id,
+                   data=StringIO(image.bytes), headers=headers)
+
+      # PUT /v1/images/{imageID}/checksum
+      checksum = compute_simple(StringIO(image.bytes), json.dumps(image_json_data))
+      checksum_headers = {'X-Docker-Checksum-Payload': checksum}
+      checksum_headers.update(headers)
+
+      self.conduct(session, 'PUT', '/v1/images/%s/checksum' % image.id,
+                   headers=checksum_headers)
+
+    # PUT /v1/repositories/{namespace}/{repository}/tags/latest
+    for tag_name in tag_names:
+      self.conduct(session, 'PUT',
+                   '/v1/repositories/%s/%s/tags/%s' % (namespace, repo_name, tag_name),
+                   data='"%s"' % images[-1].id,
+                   headers=headers)
+
+    # PUT /v1/repositories/{namespace}/{repository}/images
+    self.conduct(session, 'PUT', '/v1/repositories/%s/%s/images' % (namespace, repo_name),
+                 expected_status=204, headers=headers)
+
+    return PushResult(checksums=None, manifests=None)