Is there a way to build helloworld server code

[bharat76]

I tried extensively with following code. Get compilation error as in this post.
any help is appreciated. Thanks you @Tradias

Code

    15  #include "zprobe.grpc.pb.h"
    16
    17  #include <agrpc/asio_grpc.hpp>
    18  #include <boost/asio/co_spawn.hpp>
    19  #include <boost/asio/detached.hpp>
    20  #include <boost/asio/signal_set.hpp>
    21  #include <grpcpp/server.h>
    22  #include <grpcpp/server_builder.h>
    23
    24  #include <optional>
    25  #include <thread>
    26  namespace asio = boost::asio;
    27
    28
    29  // begin-snippet: server-side-helloworld
    30  // ---------------------------------------------------
    31  // Server-side hello world which handles exactly one request from the client before shutting down.
    32  // ---------------------------------------------------
    33  // end-snippet
    34  int main(int argc, const char** argv)
    35  {
    36      const auto port = argc >= 2 ? argv[1] : "50051";
    37      const auto host = std::string("0.0.0.0:") + port;
    38
    39      std::unique_ptr<grpc::Server> server;
    40
    41      grpc::ServerBuilder builder;
    42      agrpc::GrpcContext grpc_context{builder.AddCompletionQueue()};
    43      builder.AddListeningPort(host, grpc::InsecureServerCredentials());
    44      zprobe::ProbeService::AsyncService service;
    45      builder.RegisterService(&service);
    46      server = builder.BuildAndStart();
    47
    48      asio::co_spawn(
    49          grpc_context,
    50          [&]() -> asio::awaitable<void>
    51          {
    52              grpc::ServerContext server_context;
    53              helloworld::HelloRequest request;
    54              grpc::ServerAsyncResponseWriter<helloworld::HelloReply> writer{&server_context};
    55              co_await agrpc::request(&helloworld::Greeter::AsyncService::RequestSayHello, service, server_context,
    56                                      request, writer, asio::use_awaitable);
    57              helloworld::HelloReply response;
    58              response.set_message("Hello " + request.name());
    59              co_await agrpc::finish(writer, response, grpc::Status::OK, asio::use_awaitable);
    60          },
    61          asio::detached);
    62
    63      grpc_context.run();
    64
    65      server->Shutdown();
    66  }```

**CMAKE -- Success**
 cmake  .. "-DCMAKE_TOOLCHAIN_FILE=~/tools/vcpkg/scripts/buildsystems/vcpkg.cmake"  "-DCMAKE_PREFIX_PATH=$MY_INSTALL_DIR"

**CMakeLists.txt**
```target_link_libraries(zprobe
  PUBLIC zprobe_grpc_proto
  ${_REFLECTION}
  ${_GRPC_GRPCPP}
  ${_PROTOBUF_LIBPROTOBUF}
  asio-grpc::asio-grpc-standalone-asio)

ERROR on make

[ 83%] Building CXX object CMakeFiles/zprobe.dir/grpc_asio_server.cpp.o
/home/bbhushan/work/zprobe/grpc_asio_server.cpp:26:29: error: ‘namespace asio = boost::boost::asio;’ conflicts with a previous declaration
   26 | namespace asio = boost::asio;
      |                             ^
In file included from /home/bbhushan/tools/vcpkg/installed/x64-linux/include/asio/execution/allocator.hpp:19,
                 from /home/bbhushan/tools/vcpkg/installed/x64-linux/include/asio/execution.hpp:18,
                 from /home/bbhushan/tools/vcpkg/installed/x64-linux/include/asio/any_io_executor.hpp:22,
                 from /home/bbhushan/tools/vcpkg/installed/x64-linux/include/agrpc/detail/asio_forward.hpp:24,
                 from /home/bbhushan/tools/vcpkg/installed/x64-linux/include/agrpc/detail/default_completion_token.hpp:18,
                 from /home/bbhushan/tools/vcpkg/installed/x64-linux/include/agrpc/default_completion_token.hpp:19,
                 from /home/bbhushan/tools/vcpkg/installed/x64-linux/include/agrpc/alarm.hpp:18,
                 from /home/bbhushan/tools/vcpkg/installed/x64-linux/include/agrpc/asio_grpc.hpp:33,
                 from /home/bbhushan/work/zprobe/grpc_asio_server.cpp:17:
/home/bbhushan/tools/vcpkg/installed/x64-linux/include/asio/detail/type_traits.hpp:51:11: note: previous declaration ‘namespace asio { }’
   51 | namespace asio {
      |           ^~~~
/home/bbhushan/work/zprobe/grpc_asio_server.cpp: In function ‘int main(int, const char**)’:
/home/bbhushan/work/zprobe/grpc_asio_server.cpp:48:11: error: ‘co_spawn’ is not a member of ‘asio’
   48 |     asio::co_spawn(
      |           ^~~~~~~~
/home/bbhushan/work/zprobe/grpc_asio_server.cpp:50:24: error: ‘awaitable’ in namespace ‘asio’ does not name a template type
   50 |         [&]() -> asio::awaitable<void>
      |                        ^~~~~~~~~
/home/bbhushan/work/zprobe/grpc_asio_server.cpp:50:33: error: expected ‘{’ before ‘<’ token
   50 |         [&]() -> asio::awaitable<void>
      |                                 ^
/home/bbhushan/work/zprobe/grpc_asio_server.cpp:50:34: error: expected primary-expression before ‘void’
   50 |         [&]() -> asio::awaitable<void>
      |                                  ^~~~
/home/bbhushan/work/zprobe/grpc_asio_server.cpp:61:15: error: ‘detached’ is not a member of ‘asio’; did you mean ‘boost::asio::detached’?
   61 |         asio::detached);
      |               ^~~~~~~~
In file included from /home/bbhushan/work/zprobe/grpc_asio_server.cpp:19:
/home/bbhushan/tools/vcpkg/installed/x64-linux/include/boost/asio/detached.hpp:103:22: note: ‘boost::asio::detached’ declared here
  103 | constexpr detached_t detached;
      |                      ^~~~~~~~
make[2]: *** [CMakeFiles/zprobe.dir/build.make:76: CMakeFiles/zprobe.dir/grpc_asio_server.cpp.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:111: CMakeFiles/zprobe.dir/all] Error 2
make: *** [Makefile:91: all] Error 2

[Tradias]

Your example uses Boost.Asio, to make it use standalone Asio instead you will have to make some changes:

-    18  #include <boost/asio/co_spawn.hpp>
-    19  #include <boost/asio/detached.hpp>
-    20  #include <boost/asio/signal_set.hpp>
+    18  #include <asio/co_spawn.hpp>
+    19  #include <asio/detached.hpp>

-    26  namespace asio = boost::asio;

And of course the request that you actually want to handle. This comes from your zprobe.proto. In other words, these lines should be adjusted:

                  helloworld::HelloRequest request;
                  grpc::ServerAsyncResponseWriter<helloworld::HelloReply> writer{&server_context};
                  co_await agrpc::request(&helloworld::Greeter::AsyncService::RequestSayHello, service, server_context,
                                          request, writer, asio::use_awaitable);
                  helloworld::HelloReply response;
                  response.set_message("Hello " + request.name());

You should also be able to simplify your CMake file:

target_link_libraries(zprobe
  PUBLIC zprobe_grpc_proto
  asio-grpc::asio-grpc-standalone-asio)

[bharat76]

The following is the error after I follow above.
(It is lack of my understanding. You may please help me with this.)

I added following to CMakeLists.txt

add_definitions(-DASIO_STANDALONE)
add_definitions(-DASIO_HAS_CO_AWAIT)
add_definitions(-DASIO_SEPARATE_COMPILATION)
add_definitions(-DASIO_HAS_STD_COROUTINE)

Then I get the following error.

[ 83%] Building CXX object CMakeFiles/zprobe.dir/grpc_asio_server.cpp.o
In file included from /home/bbhushan/tools/vcpkg/installed/x64-linux/include/asio/co_spawn.hpp:22,
                 from /home/bbhushan/tools/vcpkg/installed/x64-linux/include/agrpc/detail/asio_forward.hpp:45,
                 from /home/bbhushan/tools/vcpkg/installed/x64-linux/include/agrpc/detail/default_completion_token.hpp:18,
                 from /home/bbhushan/tools/vcpkg/installed/x64-linux/include/agrpc/default_completion_token.hpp:19,
                 from /home/bbhushan/tools/vcpkg/installed/x64-linux/include/agrpc/alarm.hpp:18,
                 from /home/bbhushan/tools/vcpkg/installed/x64-linux/include/agrpc/asio_grpc.hpp:33,
                 from /home/bbhushan/work/zprobe/grpc_asio_server.cpp:17:
/home/bbhushan/tools/vcpkg/installed/x64-linux/include/asio/awaitable.hpp:23:11: fatal error: coroutine: No such file or directory
   23 | # include <coroutine>
      |

[Tradias]

I have created a minimal version of the helloworld example with standalone Asio and vcpkg here: https://github.com/Tradias/example-vcpkg-grpc/tree/asio-grpc-55. I hope that helps.

[bharat76]

@Tradias I think the example repo does not use ASIO?

[Tradias]

It uses standalone ASIO, just like in your code :), see https://github.com/Tradias/example-vcpkg-grpc/blob/asio-grpc-55/src/main.cpp

[bharat76]

Thanks @Tradias. It worked.