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/fixtures.py

@@ -0,0 +1,154 @@
+import copy
+import logging.config
+import os
+import shutil
+
+from tempfile import NamedTemporaryFile
+
+import pytest
+
+from Crypto import Random
+from flask import jsonify, g
+from flask_principal import Identity
+
+from app import storage
+from data.database import close_db_filter, configure, DerivedStorageForImage, QueueItem, Image
+from data import model
+from endpoints.csrf import generate_csrf_token
+from util.log import logfile_path
+
+from test.registry.liveserverfixture import LiveServerExecutor
+
+
+@pytest.fixture()
+def registry_server_executor(app):
+  def generate_csrf():
+    return generate_csrf_token()
+
+  def set_supports_direct_download(enabled):
+    storage.put_content(['local_us'], 'supports_direct_download', enabled)
+    return 'OK'
+
+  def delete_image(image_id):
+    image = Image.get(docker_image_id=image_id)
+    image.docker_image_id = 'DELETED'
+    image.save()
+    return 'OK'
+
+  def get_storage_replication_entry(image_id):
+    image = Image.get(docker_image_id=image_id)
+    QueueItem.select().where(QueueItem.queue_name ** ('%' + image.storage.uuid + '%')).get()
+    return 'OK'
+
+  def set_feature(feature_name, value):
+    import features
+    old_value = features._FEATURES[feature_name].value
+    features._FEATURES[feature_name].value = value
+    return jsonify({'old_value': old_value})
+
+  def clear_derived_cache():
+    DerivedStorageForImage.delete().execute()
+    return 'OK'
+
+  def clear_uncompressed_size(image_id):
+    image = model.image.get_image_by_id('devtable', 'newrepo', image_id)
+    image.storage.uncompressed_size = None
+    image.storage.save()
+    return 'OK'
+
+  def add_token():
+    another_token = model.token.create_delegate_token('devtable', 'newrepo', 'my-new-token',
+                                                      'write')
+    another_token.code = 'somecooltokencode'
+    another_token.save()
+    return 'OK'
+
+  def break_database():
+    # Close any existing connection.
+    close_db_filter(None)
+
+    # Reload the database config with an invalid connection.
+    config = copy.copy(app.config)
+    config['DB_URI'] = 'sqlite:///not/a/valid/database'
+    configure(config)
+
+    return 'OK'
+
+  def reload_app(server_hostname):
+    # Close any existing connection.
+    close_db_filter(None)
+
+    # Reload the database config.
+    app.config['SERVER_HOSTNAME'] = server_hostname[len('http://'):]
+    configure(app.config)
+
+    # Reload random after the process split, as it cannot be used uninitialized across forks.
+    Random.atfork()
+
+    # Required for anonymous calls to not exception.
+    g.identity = Identity(None, 'none')
+
+    if os.environ.get('DEBUGLOG') == 'true':
+      logging.config.fileConfig(logfile_path(debug=True), disable_existing_loggers=False)
+
+    return 'OK'
+
+  executor = LiveServerExecutor()
+  executor.register('generate_csrf', generate_csrf)
+  executor.register('set_supports_direct_download', set_supports_direct_download)
+  executor.register('delete_image', delete_image)
+  executor.register('get_storage_replication_entry', get_storage_replication_entry)
+  executor.register('set_feature', set_feature)
+  executor.register('clear_derived_cache', clear_derived_cache)
+  executor.register('clear_uncompressed_size', clear_uncompressed_size)
+  executor.register('add_token', add_token)
+  executor.register('break_database', break_database)
+  executor.register('reload_app', reload_app)
+  return executor
+
+
+@pytest.fixture()
+def liveserver_app(app, registry_server_executor, init_db_path):
+  registry_server_executor.apply_blueprint_to_app(app)
+
+  if os.environ.get('DEBUG', 'false').lower() == 'true':
+    app.config['DEBUG'] = True
+
+  # Copy the clean database to a new path. We cannot share the DB created by the
+  # normal app fixture, as it is already open in the local process.
+  local_db_file = NamedTemporaryFile(delete=True)
+  local_db_file.close()
+
+  shutil.copy2(init_db_path, local_db_file.name)
+  app.config['DB_URI'] = 'sqlite:///{0}'.format(local_db_file.name)
+  return app
+
+
+@pytest.fixture()
+def app_reloader(liveserver, registry_server_executor):
+  registry_server_executor.on(liveserver).reload_app(liveserver.url)
+  yield
+
+
+class FeatureFlagValue(object):
+  """ Helper object which temporarily sets the value of a feature flag.
+
+      Usage:
+
+      with FeatureFlagValue('ANONYMOUS_ACCESS', False, registry_server_executor.on(liveserver)):
+        ... Features.ANONYMOUS_ACCESS is False in this context ...
+  """
+
+  def __init__(self, feature_flag, test_value, executor):
+    self.feature_flag = feature_flag
+    self.test_value = test_value
+    self.executor = executor
+
+    self.old_value = None
+
+  def __enter__(self):
+    result = self.executor.set_feature(self.feature_flag, self.test_value)
+    self.old_value = result.json['old_value']
+
+  def __exit__(self, type, value, traceback):
+    self.executor.set_feature(self.feature_flag, self.old_value)