Generate python protobufs for paddle.v2.framework

Python should be able to manipulate Protobuf message because:

1. Python's `create_op_creation_methods` take the `OpProto` array to
   generate all `op_creation_methods` in RunTime.

2. All `op_creation_methods` will create an `OpDesc` and pass it to
   Paddle C++ method `CreateOp` and return the Op handle.

Here is the list of what is added in this commit:

* Add `protobuf_generate_python` if it is not defined.
  * Before cmake 3.4, `protobuf_generate_python` is not defined. Just
    copy the implementation of that function in `protobuf.cmake`
* Add `py_proto_compile` function in `cmake/generic.cmake`.
  * It follows bazel's API interface.
    * https://github.com/pubref/rules_protobuf#rules
* Add an empty package named `paddle.v2.framework`, all python code of
  `paddle::framework` will be in that package.
* Generate protobuf's python module `__init__.py` by `touch` while
  compiling.
* Change setup.py.in, make `paddle.v2.framework.proto` uses the
  generated protobuf pythons.

cmake/external/protobuf.cmake

@@ -17,6 +17,65 @@ INCLUDE(ExternalProject)
 FIND_PACKAGE(Protobuf QUIET)
 SET(PROTOBUF_FOUND "OFF")
 
+if(NOT COMMAND protobuf_generate_python)  # before cmake 3.4, protobuf_genrerate_python is not defined.
+    function(protobuf_generate_python SRCS)
+        # shameless copy from https://github.com/Kitware/CMake/blob/master/Modules/FindProtobuf.cmake
+        if(NOT ARGN)
+            message(SEND_ERROR "Error: PROTOBUF_GENERATE_PYTHON() called without any proto files")
+            return()
+        endif()
+
+        if(PROTOBUF_GENERATE_CPP_APPEND_PATH)
+            # Create an include path for each file specified
+            foreach(FIL ${ARGN})
+                get_filename_component(ABS_FIL ${FIL} ABSOLUTE)
+                get_filename_component(ABS_PATH ${ABS_FIL} PATH)
+                list(FIND _protobuf_include_path ${ABS_PATH} _contains_already)
+                if(${_contains_already} EQUAL -1)
+                    list(APPEND _protobuf_include_path -I ${ABS_PATH})
+                endif()
+            endforeach()
+        else()
+            set(_protobuf_include_path -I ${CMAKE_CURRENT_SOURCE_DIR})
+        endif()
+
+        if(DEFINED PROTOBUF_IMPORT_DIRS AND NOT DEFINED Protobuf_IMPORT_DIRS)
+            set(Protobuf_IMPORT_DIRS "${PROTOBUF_IMPORT_DIRS}")
+        endif()
+
+        if(DEFINED Protobuf_IMPORT_DIRS)
+            foreach(DIR ${Protobuf_IMPORT_DIRS})
+                get_filename_component(ABS_PATH ${DIR} ABSOLUTE)
+                list(FIND _protobuf_include_path ${ABS_PATH} _contains_already)
+                if(${_contains_already} EQUAL -1)
+                    list(APPEND _protobuf_include_path -I ${ABS_PATH})
+                endif()
+            endforeach()
+        endif()
+
+        set(${SRCS})
+        foreach(FIL ${ARGN})
+            get_filename_component(ABS_FIL ${FIL} ABSOLUTE)
+            get_filename_component(FIL_WE ${FIL} NAME_WE)
+            if(NOT PROTOBUF_GENERATE_CPP_APPEND_PATH)
+                get_filename_component(FIL_DIR ${FIL} DIRECTORY)
+                if(FIL_DIR)
+                    set(FIL_WE "${FIL_DIR}/${FIL_WE}")
+                endif()
+            endif()
+
+            list(APPEND ${SRCS} "${CMAKE_CURRENT_BINARY_DIR}/${FIL_WE}_pb2.py")
+            add_custom_command(
+                    OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/${FIL_WE}_pb2.py"
+                    COMMAND  ${Protobuf_PROTOC_EXECUTABLE} --python_out ${CMAKE_CURRENT_BINARY_DIR} ${_protobuf_include_path} ${ABS_FIL}
+                    DEPENDS ${ABS_FIL} ${Protobuf_PROTOC_EXECUTABLE}
+                    COMMENT "Running Python protocol buffer compiler on ${FIL}"
+                    VERBATIM )
+        endforeach()
+
+        set(${SRCS} ${${SRCS}} PARENT_SCOPE)
+    endfunction()
+endif()
 
 # Print and set the protobuf library information,
 # finish this cmake process and exit from this file.

cmake/generic.cmake

@@ -335,3 +335,12 @@ function(proto_library TARGET_NAME)
   protobuf_generate_cpp(proto_srcs proto_hdrs ${proto_library_SRCS})
   cc_library(${TARGET_NAME} SRCS ${proto_srcs} DEPS ${proto_library_DEPS} protobuf)
 endfunction()
+
+function(py_proto_compile TARGET_NAME)
+  set(oneValueArgs "")
+  set(multiValueArgs SRCS)
+  cmake_parse_arguments(py_proto_compile "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
+  set(py_srcs)
+  protobuf_generate_python(py_srcs ${py_proto_compile_SRCS})
+  add_custom_target(${TARGET_NAME} ALL DEPENDS ${py_srcs})
+endfunction()
\ No newline at end of file

paddle/framework/CMakeLists.txt

@@ -9,6 +9,9 @@ cc_test(enforce_test SRCS enforce_test.cc)
 proto_library(attr_type SRCS attr_type.proto)
 proto_library(op_proto SRCS op_proto.proto DEPS attr_type)
 cc_test(op_proto_test SRCS op_proto_test.cc DEPS op_proto protobuf)
-
 proto_library(op_desc SRCS op_desc.proto DEPS attr_type)
 cc_test(op_desc_test SRCS op_desc_test.cc DEPS op_desc protobuf)
+py_proto_compile(framework_py_proto SRCS attr_type.proto op_proto.proto op_desc.proto)
+# Generate an empty __init__.py to make framework_py_proto as a valid python module.
+add_custom_target(framework_py_proto_init ALL COMMAND ${CMAKE_COMMAND} -E touch __init__.py)
+add_dependencies(framework_py_proto framework_py_proto_init)

python/CMakeLists.txt

@@ -29,7 +29,7 @@ configure_file(${CMAKE_CURRENT_SOURCE_DIR}/setup.py.in
 add_custom_command(OUTPUT ${OUTPUT_DIR}/.timestamp
     COMMAND env ${py_env} ${PYTHON_EXECUTABLE} setup.py bdist_wheel
     COMMAND ${CMAKE_COMMAND} -E touch ${OUTPUT_DIR}/.timestamp
-    DEPENDS gen_proto_py ${PY_FILES} ${external_project_dependencies} ${COPY_PADDLE_MASTER})
+    DEPENDS gen_proto_py framework_py_proto ${PY_FILES} ${external_project_dependencies} ${COPY_PADDLE_MASTER})
 
 add_custom_target(paddle_python ALL DEPENDS
     ${OUTPUT_DIR}/.timestamp)
@@ -43,6 +43,7 @@ if (WITH_TESTING)
     add_subdirectory(paddle/v2/tests)
     add_subdirectory(paddle/v2/reader/tests)
     add_subdirectory(paddle/v2/plot/tests)
+    add_subdirectory(paddle/v2/framework/tests)
   endif()
 endif()
 install(DIRECTORY ${PADDLE_PYTHON_PACKAGE_DIR}

python/paddle/v2/framework/__init__.py

+__all__ = ['proto']

python/paddle/v2/framework/tests/CMakeLists.txt

+add_python_test(test_framework test_protobuf.py)

python/paddle/v2/framework/tests/test_protobuf.py

+import paddle.v2.framework.proto.op_proto_pb2
+import paddle.v2.framework.proto.attr_type_pb2
+import unittest
+
+
+class TestFrameworkProto(unittest.TestCase):
+    def test_all(self):
+        op_proto_lib = paddle.v2.framework.proto.op_proto_pb2
+        attr_type_lib = paddle.v2.framework.proto.attr_type_pb2
+        op_proto = op_proto_lib.OpProto()
+        ipt0 = op_proto.inputs.add()
+        ipt0.name = "a"
+        ipt0.comment = "the input of cosine op"
+        ipt1 = op_proto.inputs.add()
+        ipt1.name = "b"
+        ipt1.comment = "the other input of cosine op"
+        opt = op_proto.outputs.add()
+        opt.name = "output"
+        opt.comment = "the output of cosine op"
+        op_proto.comment = "cosine op, output = scale*cos(a, b)"
+        attr = op_proto.attrs.add()
+        attr.name = "scale"
+        attr.comment = "scale of cosine op"
+        attr.type = attr_type_lib.FLOAT
+        op_proto.type = "cos"
+        self.assertTrue(op_proto.IsInitialized())

python/setup.py.in

@@ -9,7 +9,9 @@ packages=['paddle',
           'paddle.v2.dataset',
           'paddle.v2.reader',
           'paddle.v2.master',
-          'paddle.v2.plot']
+          'paddle.v2.plot',
+          'paddle.v2.framework',
+          'paddle.v2.framework.proto']
 
 setup_requires=["requests",
                 "numpy",
@@ -29,6 +31,9 @@ setup(name='paddle',
       packages=packages,
       package_data={'paddle.v2.master': ['${paddle_master_LIB_NAME}'], },
       package_dir={
-          '': '${CMAKE_CURRENT_SOURCE_DIR}'
+          '': '${CMAKE_CURRENT_SOURCE_DIR}',
+          # The paddle.v2.framework.proto will be generated while compiling.
+          # So that package points to other directory.
+          'paddle.v2.framework.proto': '${CMAKE_BINARY_DIR}/paddle/framework'
       },
 )