Complete the diff generating functionality.

endpoints/registry.py

@@ -1,4 +1,3 @@
-
 import logging
 import json
 
@@ -11,7 +10,7 @@ import storage
 
 from app import app
 from auth.auth import process_auth, extract_namespace_repo_from_session
-from util import checksums
+from util import checksums, changes
 from auth.permissions import (ReadRepositoryPermission,
                               ModifyRepositoryPermission)
 from data import model
@@ -315,6 +314,49 @@ def delete_repository_storage(namespace, repository):
 
 
 def process_image_changes(namespace, repository, image_id):
-  return
+  logger.debug('Generating diffs for image: %s' % image_id)
+
+  image_diffs_path = store.image_file_diffs_path(namespace, repository,
+                                                 image_id)
+  if store.exists(image_diffs_path):
+    logger.debug('Diffs already exist for image: %s' % image_id)
+    return
+
   image = model.get_image_by_id(namespace, repository, image_id)
-  model.get_parent_images()
+  parents = model.get_parent_images(image)
+
+  # Compute the diffs and fs for the parent first if necessary
+  parent_trie_path = None
+  if parents:
+    parent_trie_path = process_image_changes(namespace, repository,
+                                             parents[-1].docker_image_id)
+
+  # Read in the collapsed layer state of the filesystem for the parent
+  parent_trie = changes.empty_fs()
+  if parent_trie_path:
+    with store.stream_read_file(parent_trie_path) as parent_trie_stream:
+      parent_trie.read(parent_trie_stream)
+
+  # Read in the file entries from the layer tar file
+  layer_path = store.image_layer_path(namespace, repository, image_id)
+  with store.stream_read_file(layer_path) as layer_tar_stream:
+    removed_files = set()
+    layer_files = changes.files_and_dirs_from_tar(layer_tar_stream,
+                                                  removed_files)
+
+    new_metadata = changes.compute_new_diffs_and_fs(parent_trie, layer_files,
+                                                    removed_files)
+  (new_trie, added, changed, removed) = new_metadata
+
+  # Write out the new trie
+  new_trie_path = store.image_file_trie_path(namespace, repository, image_id)
+  store.put_content(new_trie_path, new_trie.tobytes())
+
+  # Write out the diffs
+  diffs = {}
+  sections = ('added', 'changed', 'removed')
+  for section, source_trie in zip(sections, new_metadata[1:]):
+    diffs[section] = list(source_trie)
+  store.put_content(image_diffs_path, json.dumps(diffs, indent=2))
+
+  return new_trie_path