swarmbucket: allow overriding config

appengine/cr-buildbucket/protoutil.py

Index: appengine/cr-buildbucket/protoutil.py
diff --git a/appengine/cr-buildbucket/protoutil.py b/appengine/cr-buildbucket/protoutil.py
new file mode 100644
index 0000000000000000000000000000000000000000..fbab8b78239fabac3666f2acc9884b7008e16954
--- /dev/null
+++ b/appengine/cr-buildbucket/protoutil.py
@@ -0,0 +1,62 @@
+# Copyright 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Converts proto messages from JSONPB."""
+
+from google.protobuf import descriptor
+
+
+SCALAR_TYPES = {
+  descriptor.FieldDescriptor.TYPE_BOOL,
+  descriptor.FieldDescriptor.TYPE_BYTES,
+  descriptor.FieldDescriptor.TYPE_DOUBLE,
+  descriptor.FieldDescriptor.TYPE_FIXED32,
+  descriptor.FieldDescriptor.TYPE_FIXED64,
+  descriptor.FieldDescriptor.TYPE_FLOAT,
+  descriptor.FieldDescriptor.TYPE_INT32,
+  descriptor.FieldDescriptor.TYPE_INT64,
+  descriptor.FieldDescriptor.TYPE_SFIXED32,
+  descriptor.FieldDescriptor.TYPE_SFIXED64,
+  descriptor.FieldDescriptor.TYPE_SINT32,
+  descriptor.FieldDescriptor.TYPE_SINT64,
+  descriptor.FieldDescriptor.TYPE_STRING,
+  descriptor.FieldDescriptor.TYPE_UINT32,
+  descriptor.FieldDescriptor.TYPE_UINT64,
+}
+
+
+def merge_dict(data, msg):
+  """Merges |data| dict into |msg|, recursively.
+
+  Raises:
+    TypeError if a field in |data| is not defined in |msg| or has an
+    unsupported type.
+  """
+  if not isinstance(data, dict):
+    raise TypeError('data is not a dict')
+  for name, value in data.iteritems():
+    f = msg.DESCRIPTOR.fields_by_name.get(name)
+    if not f:
+      raise TypeError('unexpected property %r' % name)
+    scalar_f = f.type in SCALAR_TYPES
+    msg_f = f.type == descriptor.FieldDescriptor.TYPE_MESSAGE
+    if not scalar_f and not msg_f:  # pragma: no cover
+      raise TypeError('field %s has unsupported type %r', name, f.type)
+
+    try:
+      if f.label == descriptor.FieldDescriptor.LABEL_REPEATED:
+        container = getattr(msg, name)
+        for v in value:
+          if scalar_f:
+            container.append(v)
+          else:
+            submsg = container.add()
+            merge_dict(v, submsg)
+      else:
+        if scalar_f:
+          setattr(msg, name, value)
+        else:
+          merge_dict(value, getattr(msg, name))
+    except TypeError as ex:
+      raise TypeError('%s: %s' % (name, ex))