Change back to using a docker load format

util/dockerloadformat.py

@@ -0,0 +1,115 @@
+from util.gzipwrap import GzipWrap
+from util.streamlayerformat import StreamLayerMerger
+from app import app
+
+import copy
+import json
+import tarfile
+
+def build_docker_load_stream(namespace, repository, tag, synthetic_image_id,
+                             layer_json, get_image_iterator, get_layer_iterator):
+  """ Builds and streams a synthetic .tar.gz that represents a squashed version
+      of the given layers, in `docker load` V1 format.
+  """
+  return GzipWrap(_import_format_generator(namespace, repository, tag,
+                                           synthetic_image_id, layer_json,
+                                           get_image_iterator, get_layer_iterator))
+
+
+def _import_format_generator(namespace, repository, tag, synthetic_image_id,
+                             layer_json, get_image_iterator, get_layer_iterator):
+
+  # Docker import V1 Format (.tar):
+  #  repositories - JSON file containing a repo -> tag -> image map
+  #  {image ID folder}:
+  #     json - The layer JSON
+  #     layer.tar - The TARed contents of the layer
+  #     VERSION - The docker import version: '1.0'
+  layer_merger = StreamLayerMerger(get_layer_iterator)
+  
+  # Yield the repositories file:
+  synthetic_layer_info = {}
+  synthetic_layer_info[tag + '.squash'] = synthetic_image_id
+
+  hostname = app.config['SERVER_HOSTNAME']
+  repositories = {}
+  repositories[hostname + '/' + namespace + '/' + repository] = synthetic_layer_info
+
+  yield _tar_file('repositories', json.dumps(repositories))
+
+  # Yield the image ID folder.
+  yield _tar_folder(synthetic_image_id)
+
+  # Yield the JSON layer data.
+  layer_json = _build_layer_json(layer_json, synthetic_image_id)
+  yield _tar_file(synthetic_image_id + '/json', json.dumps(layer_json))
+
+  # Yield the VERSION file.
+  yield _tar_file(synthetic_image_id + '/VERSION', '1.0')
+
+  # Yield the merged layer data's header.
+  estimated_file_size = 0
+  for image in get_image_iterator():
+    estimated_file_size += image.storage.uncompressed_size or 0
+
+  yield _tar_file_header(synthetic_image_id + '/layer.tar', estimated_file_size)
+
+  # Yield the contents of the merged layer.
+  yielded_size = 0
+  for entry in layer_merger.get_generator():
+    yield entry
+    yielded_size += len(entry)
+
+  # If the yielded size is less than the estimated size (which is likely), fill the rest with
+  # zeros.
+  if yielded_size < estimated_file_size:
+    yield '\0' * (estimated_file_size - yielded_size)
+
+  # Yield any file padding to 512 bytes that is necessary.
+  yield _tar_file_padding(estimated_file_size)
+
+  # Last two records are empty in TAR spec.
+  yield '\0' * 512
+  yield '\0' * 512
+
+
+def _build_layer_json(layer_json, synthetic_image_id):
+  updated_json = copy.deepcopy(layer_json)
+  updated_json['id'] = synthetic_image_id
+
+  if 'parent' in updated_json:
+    del updated_json['parent']
+      
+  if 'config' in updated_json and 'Image' in updated_json['config']:
+    updated_json['config']['Image'] = synthetic_image_id
+
+  if 'container_config' in updated_json and 'Image' in updated_json['container_config']:
+    updated_json['container_config']['Image'] = synthetic_image_id
+
+  return updated_json
+
+
+def _tar_file(name, contents):
+  length = len(contents)
+  tar_data = _tar_file_header(name, length)
+  tar_data += contents
+  tar_data += _tar_file_padding(length)
+  return tar_data
+
+
+def _tar_file_padding(length):
+  if length % 512 != 0:
+    return '\0' * (512 - (length % 512))
+
+
+def _tar_file_header(name, file_size):
+  info = tarfile.TarInfo(name=name)
+  info.type = tarfile.REGTYPE
+  info.size = file_size
+  return info.tobuf()
+
+
+def _tar_folder(name):
+  info = tarfile.TarInfo(name=name)
+  info.type = tarfile.DIRTYPE
+  return info.tobuf()