Fix handling of four byte utf8 manifests

- Adds the charset: utf-8 to all the manifest responses
- Makes sure we connect to MySQL in utf8mb4 mode, to ensure we can properly read and write 4-byte utf8 strings
- Adds tests for all of the above

data/registry_model/test/test_interface.py

@@ -1,3 +1,5 @@
+# -*- coding: utf-8 -*-
+
 import hashlib
 import json
 import uuid
@@ -864,3 +866,33 @@ def test_known_issue_schema1(registry_model):
   assert found.digest == digest
   assert found.internal_manifest_bytes.as_encoded_str() == manifest.bytes.as_encoded_str()
   assert found.get_parsed_manifest().digest == digest
+
+
+def test_unicode_emoji(registry_model):
+  builder = DockerSchema1ManifestBuilder('devtable', 'simple', 'latest')
+  builder.add_layer('sha256:abcde', json.dumps({
+    'id': 'someid',
+    'author': u'😱',
+  }, ensure_ascii=False))
+
+  manifest = builder.build(ensure_ascii=False)
+  manifest._validate()
+
+  for blob_digest in manifest.local_blob_digests:
+    _populate_blob(blob_digest)
+
+  # Create the manifest in the database.
+  repository_ref = registry_model.lookup_repository('devtable', 'simple')
+  created_manifest, _ = registry_model.create_manifest_and_retarget_tag(repository_ref, manifest,
+                                                                        'latest', storage)
+  assert created_manifest
+  assert created_manifest.digest == manifest.digest
+  assert (created_manifest.internal_manifest_bytes.as_encoded_str() ==
+          manifest.bytes.as_encoded_str())
+
+  # Look it up again and validate.
+  found = registry_model.lookup_manifest_by_digest(repository_ref, manifest.digest, allow_dead=True)
+  assert found
+  assert found.digest == manifest.digest
+  assert found.internal_manifest_bytes.as_encoded_str() == manifest.bytes.as_encoded_str()
+  assert found.get_parsed_manifest().digest == manifest.digest