Revert "Remove completely create_data_config_proto"

This reverts commit ab279bee.

python/paddle/trainer/config_parser.py

@@ -894,6 +894,30 @@ class MaxOut(Cfg):
         self.add_keys(locals())
 
 
+def create_data_config_proto(async_load_data=False,
+             constant_slots=None,
+             data_ratio=1,
+             is_main_data=True,
+             usage_ratio=None):
+    # default: all sub dataproviders are treat as "main data".
+    # see proto/DataConfig.proto for is_main_data
+    data_config = DataConfig()
+
+    data_config.async_load_data = async_load_data
+
+    if constant_slots:
+        data_config.constant_slots.extend(constant_slots)
+    data_config.data_ratio = data_ratio
+    data_config.is_main_data = is_main_data
+
+    usage_ratio = default(usage_ratio, settings_deprecated["usage_ratio"])
+    config_assert(usage_ratio >= 0 and usage_ratio <= 1,
+                  "The range of usage_ratio is [0, 1]")
+    data_config.usage_ratio = usage_ratio
+
+    return data_config
+
+
 @config_func
 def SimpleData(files=None,
                feat_dim=None,

python/paddle/trainer_config_helpers/data_sources.py

@@ -14,7 +14,6 @@
 """
 Data Sources are helpers to define paddle training data or testing data.
 """
-import paddle.proto.DataConfig_pb2
 from paddle.trainer.config_parser import *
 from .utils import deprecated
 
@@ -196,7 +195,7 @@ def define_py_data_sources2(train_list, test_list, module, obj, args=None):
 
     def py_data2(files, load_data_module, load_data_object, load_data_args,
                  **kwargs):
-        data = paddle.proto.DataConfig_pb2.DataConfig()
+        data = create_data_config_proto()
         data.type = 'py2'
         data.files = files
         data.load_data_module = load_data_module