cmake "superbuild" example using externalprojects

2 files changed, 152 insertions, 33 deletions

diff --git a/examples/cpp/helloworld/CMakeLists.txt b/examples/cpp/helloworld/CMakeLists.txt
index c3ce4d5ba6..4f7d3fdddb 100644
--- a/examples/cpp/helloworld/CMakeLists.txt
+++ b/examples/cpp/helloworld/CMakeLists.txt
@@ -1,7 +1,24 @@
-# Minimum CMake required

+# Copyright 2018 gRPC authors.

+#

+# Licensed under the Apache License, Version 2.0 (the "License");

+# you may not use this file except in compliance with the License.

+# You may obtain a copy of the License at

+#

+#     http://www.apache.org/licenses/LICENSE-2.0

+#

+# Unless required by applicable law or agreed to in writing, software

+# distributed under the License is distributed on an "AS IS" BASIS,

+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

+# See the License for the specific language governing permissions and

+# limitations under the License.

+#

+# cmake build file for C++ helloworld example.

+# Assumes protobuf and gRPC have been installed using cmake.

+# See cmake_externalproject/CMakeLists.txt for all-in-one cmake build

+# that automatically builds all the dependencies before building helloworld.

+

 cmake_minimum_required(VERSION 2.8)

 

-# Project

 project(HelloWorld C CXX)

 

 if(NOT MSVC)

@@ -10,57 +27,43 @@ else()
   add_definitions(-D_WIN32_WINNT=0x600)

 endif()

 

-# Protobuf

-# NOTE: we cannot use "CONFIG" mode here because protobuf-config.cmake

-# is broken when used with CMAKE_INSTALL_PREFIX

-find_package(Protobuf REQUIRED)

+# Find Protobuf installation

+# Looks for protobuf-config.cmake file installed by Protobuf's cmake installation.

+set(protobuf_MODULE_COMPATIBLE TRUE)

+find_package(Protobuf CONFIG REQUIRED)

 message(STATUS "Using protobuf ${protobuf_VERSION}")

 

-# {Protobuf,PROTOBUF}_FOUND is defined based on find_package type ("MODULE" vs "CONFIG").

-# For "MODULE", the case has also changed between cmake 3.5 and 3.6.

-# We use the legacy uppercase version for *_LIBRARIES AND *_INCLUDE_DIRS variables

-# as newer cmake versions provide them too for backward compatibility.

-if(Protobuf_FOUND OR PROTOBUF_FOUND)

-  if(TARGET protobuf::libprotobuf)

-    set(_PROTOBUF_LIBPROTOBUF protobuf::libprotobuf)

-  else()

-    set(_PROTOBUF_LIBPROTOBUF ${PROTOBUF_LIBRARIES})

-    include_directories(${PROTOBUF_INCLUDE_DIRS})

-  endif()

-  if(TARGET protobuf::protoc)

-    set(_PROTOBUF_PROTOC $<TARGET_FILE:protobuf::protoc>)

-  else()

-    set(_PROTOBUF_PROTOC ${PROTOBUF_PROTOC_EXECUTABLE})

-  endif()

-else()

-  message(WARNING "Failed to locate libprotobuf and protoc!")

-endif()

+set(_PROTOBUF_LIBPROTOBUF protobuf::libprotobuf)

+set(_PROTOBUF_PROTOC $<TARGET_FILE:protobuf::protoc>)

 

-# gRPC

+# Find gRPC installation

+# Looks for gRPCConfig.cmake file installed by gRPC's cmake installation.

 find_package(gRPC CONFIG REQUIRED)

 message(STATUS "Using gRPC ${gRPC_VERSION}")

 

 # gRPC C++ plugin

-get_target_property(gRPC_CPP_PLUGIN_EXECUTABLE gRPC::grpc_cpp_plugin

-    IMPORTED_LOCATION_RELEASE)

+set(_GRPC_CPP_PLUGIN_EXECUTABLE $<TARGET_FILE:gRPC::grpc_cpp_plugin>)

 

 # Proto file

 get_filename_component(hw_proto "../../protos/helloworld.proto" ABSOLUTE)

 get_filename_component(hw_proto_path "${hw_proto}" PATH)

 

 # Generated sources

-protobuf_generate_cpp(hw_proto_srcs hw_proto_hdrs "${hw_proto}")

+set(hw_proto_srcs "${CMAKE_CURRENT_BINARY_DIR}/helloworld.pb.cc")

+set(hw_proto_hdrs "${CMAKE_CURRENT_BINARY_DIR}/helloworld.pb.h")

 set(hw_grpc_srcs "${CMAKE_CURRENT_BINARY_DIR}/helloworld.grpc.pb.cc")

 set(hw_grpc_hdrs "${CMAKE_CURRENT_BINARY_DIR}/helloworld.grpc.pb.h")

 add_custom_command(

-      OUTPUT "${hw_grpc_srcs}" "${hw_grpc_hdrs}"

+      OUTPUT "${hw_proto_srcs}" "${hw_proto_hdrs}" "${hw_grpc_srcs}" "${hw_grpc_hdrs}"

       COMMAND ${_PROTOBUF_PROTOC}

-      ARGS --grpc_out "${CMAKE_CURRENT_BINARY_DIR}" -I "${hw_proto_path}"

-        --plugin=protoc-gen-grpc="${gRPC_CPP_PLUGIN_EXECUTABLE}"

+      ARGS --grpc_out "${CMAKE_CURRENT_BINARY_DIR}"

+        --cpp_out "${CMAKE_CURRENT_BINARY_DIR}"

+        -I "${hw_proto_path}"

+        --plugin=protoc-gen-grpc="${_GRPC_CPP_PLUGIN_EXECUTABLE}"

         "${hw_proto}"

       DEPENDS "${hw_proto}")

 

-# Generated include directory

+# Include generated *.pb.h files

 include_directories("${CMAKE_CURRENT_BINARY_DIR}")

 

 # Targets greeter_[async_](client|server)

diff --git a/examples/cpp/helloworld/cmake_externalproject/CMakeLists.txt b/examples/cpp/helloworld/cmake_externalproject/CMakeLists.txt
new file mode 100644
index 0000000000..9fbdf071a8
--- /dev/null
+++ b/examples/cpp/helloworld/cmake_externalproject/CMakeLists.txt
@@ -0,0 +1,116 @@
+# Copyright 2018 gRPC authors.

+#

+# Licensed under the Apache License, Version 2.0 (the "License");

+# you may not use this file except in compliance with the License.

+# You may obtain a copy of the License at

+#

+#     http://www.apache.org/licenses/LICENSE-2.0

+#

+# Unless required by applicable law or agreed to in writing, software

+# distributed under the License is distributed on an "AS IS" BASIS,

+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

+# See the License for the specific language governing permissions and

+# limitations under the License.

+#

+# cmake "superbuild" file for C++ helloworld example.

+# This build file demonstrates how to build the helloworld project

+# and all its dependencies in a single cmake build (hence "superbuild")

+# that is easy to build and maintain.

+# cmake's ExternalProject_Add() is used to import all the sub-projects,

+# including the "helloworld" project itself.

+# See https://blog.kitware.com/cmake-superbuilds-git-submodules/

+

+cmake_minimum_required(VERSION 2.8)

+

+# Project

+project(HelloWorld-SuperBuild C CXX)

+

+include(ExternalProject)

+

+# Builds c-ares project from the git submodule.

+# Note: For all external projects, instead of using checked-out code, one could

+# specify GIT_REPOSITORY and GIT_TAG to have cmake download the dependency directly,

+# without needing to add a submodule to your project.

+ExternalProject_Add(c-ares

+  PREFIX c-ares

+  SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../../../../third_party/cares/cares"

+  CMAKE_CACHE_ARGS

+        -DCARES_SHARED:BOOL=OFF

+        -DCARES_STATIC:BOOL=ON

+        -DCARES_STATIC_PIC:BOOL=ON

+        -DCMAKE_INSTALL_PREFIX:PATH=${CMAKE_CURRENT_BINARY_DIR}/c-ares

+)

+

+# Builds protobuf project from the git submodule.

+ExternalProject_Add(protobuf

+  PREFIX protobuf

+  SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../../../../third_party/protobuf/cmake"

+  CMAKE_CACHE_ARGS

+        -Dprotobuf_BUILD_TESTS:BOOL=OFF

+        -Dprotobuf_WITH_ZLIB:BOOL=OFF

+        -Dprotobuf_MSVC_STATIC_RUNTIME:BOOL=OFF

+        -DCMAKE_INSTALL_PREFIX:PATH=${CMAKE_CURRENT_BINARY_DIR}/protobuf

+)

+

+# Builds zlib project from the git submodule.

+ExternalProject_Add(zlib

+  PREFIX zlib

+  SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../../../../third_party/zlib"

+  CMAKE_CACHE_ARGS

+        -DCMAKE_INSTALL_PREFIX:PATH=${CMAKE_CURRENT_BINARY_DIR}/zlib

+)

+

+# the location where protobuf-config.cmake will be installed varies by platform

+if (WIN32)

+  set(_FINDPACKAGE_PROTOBUF_CONFIG_DIR "${CMAKE_CURRENT_BINARY_DIR}/protobuf/cmake")

+else()

+  set(_FINDPACKAGE_PROTOBUF_CONFIG_DIR "${CMAKE_CURRENT_BINARY_DIR}/protobuf/lib/cmake/protobuf")

+endif()

+

+# if OPENSSL_ROOT_DIR is set, propagate that hint path to the external projects with OpenSSL dependency.

+set(_CMAKE_ARGS_OPENSSL_ROOT_DIR "")

+if (OPENSSL_ROOT_DIR)

+  set(_CMAKE_ARGS_OPENSSL_ROOT_DIR "-DOPENSSL_ROOT_DIR:PATH=${OPENSSL_ROOT_DIR}")

+endif()

+

+# Builds gRPC based on locally checked-out sources and set arguments so that all the dependencies

+# are correctly located.

+ExternalProject_Add(grpc

+  PREFIX grpc

+  SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../../../.."

+  CMAKE_CACHE_ARGS

+        -DgRPC_INSTALL:BOOL=ON

+        -DgRPC_BUILD_TESTS:BOOL=OFF

+        -DgRPC_PROTOBUF_PROVIDER:STRING=package

+        -DgRPC_PROTOBUF_PACKAGE_TYPE:STRING=CONFIG

+        -DProtobuf_DIR:PATH=${_FINDPACKAGE_PROTOBUF_CONFIG_DIR}

+        -DgRPC_ZLIB_PROVIDER:STRING=package

+        -DZLIB_ROOT:STRING=${CMAKE_CURRENT_BINARY_DIR}/zlib

+        -DgRPC_CARES_PROVIDER:STRING=package

+        -Dc-ares_DIR:PATH=${CMAKE_CURRENT_BINARY_DIR}/c-ares/lib/cmake/c-ares

+        -DgRPC_SSL_PROVIDER:STRING=package

+        ${_CMAKE_ARGS_OPENSSL_ROOT_DIR}

+        -DCMAKE_INSTALL_PREFIX:PATH=${CMAKE_CURRENT_BINARY_DIR}/grpc

+  DEPENDS c-ares protobuf zlib

+)

+

+# Build the helloworld projects itself using a CMakeLists.txt that assumes all the dependencies

+# have already been installed.

+# Even though helloworld is not really an "external project" from perspective of this build,

+# we are still importing it using ExternalProject_Add because that allows us to use find_package()

+# to locate all the dependencies (if we were building helloworld directly in this build we,

+# we would have needed to manually import the libraries as opposed to reusing targets exported by

+# gRPC and protobuf).

+ExternalProject_Add(helloworld

+  PREFIX helloworld

+  SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/.."

+  BINARY_DIR "${CMAKE_CURRENT_BINARY_DIR}/helloworld"

+  INSTALL_COMMAND ""

+  CMAKE_CACHE_ARGS

+        -DProtobuf_DIR:PATH=${_FINDPACKAGE_PROTOBUF_CONFIG_DIR}

+        -Dc-ares_DIR:PATH=${CMAKE_CURRENT_BINARY_DIR}/c-ares/lib/cmake/c-ares

+        -DZLIB_ROOT:STRING=${CMAKE_CURRENT_BINARY_DIR}/zlib

+        ${_CMAKE_ARGS_OPENSSL_ROOT_DIR}

+        -DgRPC_DIR:PATH=${CMAKE_CURRENT_BINARY_DIR}/grpc/lib/cmake/grpc

+  DEPENDS protobuf grpc

+)