为 cpp 项目设置 protobuf 和 grpc 的正确方法是什么？

Question

I have a cpp project, and I want to build everything from source, to get latest things likned in. So under my project root I've created a 3rd_party folder and assemble following script:

sudo apt-get install autoconf automake libtool curl make g++ unzip -y
git clone https://github.com/google/protobuf.git
cd protobuf
git submodule update --init --recursive
./autogen.sh
./configure
make
make check
sudo make install
sudo ldconfig
cd ..

echo installing grpc
git clone --recurse-submodules -b v1.43.0 https://github.com/grpc/grpc
export MY_INSTALL_DIR=$HOME/.local
be sure that its exists
cd grpc
mkdir -p cmake/build
pushd cmake/build
cmake -DgRPC_INSTALL=ON       -DgRPC_BUILD_TESTS=OFF       -DCMAKE_INSTALL_PREFIX=$MY_INSTALL_DIR       ../..
make -j
make install
popd

i've encountered following flaws:

• grpc v1.43.0 clones 3rd party submodule protoc v3.18, which after build has problems - protoc binary says "cpp plugin not found", when trying to generate

To overcome that I've copied sources obtained in the first part of script, to 3rd party subfolder of second part, to gurantee it to be 3.19 - then after compilation protoc working great, plugins are in place, and grpc is linked against latest version.

Very weird issue, needs understanding why it clones outdated version, and why 3.18 has no plugins under same build parameters as 3.19

• in cmakelists find_package(Protobuf REQUIRED) fails at all

• find_package( gRPC REQUIRED ) is not operating properly:

Found package configuration file:
[cmake] 
[cmake]     /home/a/.local/lib/cmake/grpc/gRPCConfig.cmake
[cmake] 
[cmake]   but it set gRPC_FOUND to FALSE so package "gRPC" is considered to be NOT
[cmake]   FOUND.  Reason given by package:
[cmake] 
[cmake]   The following imported targets are referenced, but are missing:
[cmake]   protobuf::libprotobuf protobuf::libprotoc

---

Question

How can I write script, that in an empty folder will get me everything, related to grpc 3rd party libs and tools, that I need for project?

Answer 1

Here are the steps I took:

$ mkdir .local
$ export INSTALL_PREFIX="$PWD/.local"
$ export CMAKE_GENERATOR=Ninja  # optional, but recommended

$ git clone --recurse-submodules -b v3.19.3 --depth 1 https://github.com/google/protobuf.git
$ pushd protobuf
$ ./autogen.sh
$ ./configure --prefix=$INSTALL_PREFIX
$ make -j$(nproc)
$ make install
$ popd

$ git clone --recurse-submodules -b v1.43.0 --depth 1 https://github.com/grpc/grpc.git
$ cmake -S grpc -B .build/grpc \
    -DCMAKE_BUILD_TYPE=Release \
    -DCMAKE_INSTALL_PREFIX=$INSTALL_PREFIX \
    -DCMAKE_PREFIX_PATH=$INSTALL_PREFIX \
    -DgRPC_INSTALL=ON \
    -DgRPC_BUILD_TESTS=OFF \
    -DgRPC_PROTOBUF_PROVIDER=package \
    -DABSL_PROPAGATE_CXX_STD=ON
$ cmake --build .build/grpc --target install
...

$ mkdir example
$ echo "int main () { return 0; }" > example/main.cpp
$ vim example/CMakeLists.txt
$ cat example/CMakeLists.txt
cmake_minimum_required(VERSION 3.22)
project(example)

find_package(gRPC REQUIRED)

add_executable(main main.cpp)
target_link_libraries(main PRIVATE gRPC::grpc++)

$ cmake -S example -B .build/example \
    -DCMAKE_BUILD_TYPE=Release \
    -DCMAKE_PREFIX_PATH=$INSTALL_PREFIX
$ cmake --build .build/example
...

I build protobuf separately because gRPC doesn't set up its dependencies in CMake correctly when using its internal protobuf build (I tried both ways). This involves passing --prefix to protobuf's ./configure script and passing -DgRPC_PROTOBUF_PROVIDER=package to gRPC's CMake build. The latter is a gRPC-specific variable that tells it not to build protobuf, but to search for it instead. I tell gRPC where to find protobuf by setting CMAKE_PREFIX_PATH , which is a standard variable.