Add support for read slave databases.

tools/migrateimage.py

@@ -0,0 +1,67 @@
+import argparse
+import logging
+
+from data import model
+from data.database import ImageStoragePlacement, ImageStorageLocation
+from app import storage
+
+
+logger = logging.getLogger(__name__)
+
+
+PATHSPECS = [
+  (storage.image_json_path, True),
+  (storage.image_layer_path, True),
+  (storage.image_ancestry_path, True),
+  (storage.image_file_trie_path, False),
+  (storage.image_file_diffs_path, False),
+]
+
+
+def migrate_image(image, destination_location):
+  logger.debug('Migrating image: %s -> %s', image.docker_image_id, destination_location.name)
+  destination_location_set = {destination_location.name}
+
+  for path_func, required in PATHSPECS:
+    path = path_func(image.storage.uuid)
+
+    if storage.exists(image.storage.locations, path):
+      if not storage.exists(destination_location_set, path):
+        logger.debug('Migrating path: %s', path)
+
+        with storage.stream_read_file(image.storage.locations, path) as file_to_migrate:
+          storage.stream_write(destination_location_set, path, file_to_migrate)
+      else:
+        logger.debug('File already present in destination: %s', path)
+    elif required:
+      raise RuntimeError('Required file not present in image to migrate: %s', path)
+
+  # Successfully migrated, now write the placement
+  ImageStoragePlacement.create(location=destination_location, storage=image.storage)
+
+parser = argparse.ArgumentParser(description='Replicate an image storage.')
+parser.add_argument('--namespace', type=str, required=True,
+                    help='Namespace for the repository containing the image to be replicated')
+parser.add_argument('--repository', type=str, required=True,
+                    help='Name for the repository containing the image to be replicated')
+parser.add_argument('--imageid', type=str, default=None,
+                    help='Specific image to migrate, entire repo will be migrated if omitted')
+parser.add_argument('--to', type=str, required=True,
+                    help='Storage region to which the data should be replicated')
+
+if __name__ == "__main__":
+  logging.basicConfig(level=logging.DEBUG)
+  logging.getLogger('boto').setLevel(logging.CRITICAL)
+
+  args = parser.parse_args()
+
+  location = ImageStorageLocation.get(name=args.to)
+
+  images = []
+  if args.imageid is not None:
+    images = [model.get_image_by_id(args.namespace, args.repository, args.imageid)]
+  else:
+    images = model.get_repository_images(args.namespace, args.repository)
+
+  for img in images:
+    migrate_image(img, location)