forked from BigfootDev/flatbuffers
da67c0a71f
* Rework flatbuffers + gRPC integration - Introduce `flatbuffers::grpc::Message<T>`, a `grpc_slice`-backed message buffer that handles refcounting and allows flatbuffers to transfer ownership to gRPC efficiently. This replaces `flatbuffers::BufferRef<T>`, which required a copy call and was also unsafe w.r.t. buffer lifetime. - Introduce `flatbuffers::grpc::MessageBuilder`, a gRPC-specific builder that forces a `grpc_slice`-backed allocator and also adds some helpful `Message<T>`-related methods. - Update serializers accordingly (now zero-copy between flatbuffers and gRPC). * gRPC: verify messages by default, but allow user to override * gRPC: fix some formatting issues * Disable verification by default, but add helper method * Make FlatBufferBuilder fields protected + remove vec accessor * Use bool add_ref parameter to toggle refcount incr * Remove unnecessary inline specifiers * Fix formatting * Use auto * Remove empty lines * Use grpc_slice helper macros * Simplify reset code * Disable Message copy ctor and assignment by default * Remove unused member * Enable gRPC verification by default * Use auto * Bake in message verification (remove template specialization) * Add RoundUp func * Consolidate gRPC message copy flag * Make vector_downward allocations fully lazy * Test message verification failure code/message * Add grpctest verification test comments * Simplify reallocate implementation * Make initial_size a size_t * Use ternary op for growth_policy * Use truthiness rather than dont explicit nullptr check * Indent preprocessor directives * Remove grpc message copy/assignment * Fix a few bugs * Add gRPC example * Add basic gRPC docs * Use doxygen EXAMPLE_PATH + @include * Reference example fbs in grpc docs * Move gRPC examples into grpc/samples * Fix pointer/reference formatting * Use std::function rather than templated callback func * Create fresh message builder for each request * Use Clear() in Reset() impl * Use FLATBUFFERS_CONSTEXPR
81 lines
2.7 KiB
C++
81 lines
2.7 KiB
C++
#include "greeter.grpc.fb.h"
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#include "greeter_generated.h"
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#include <grpc++/grpc++.h>
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#include <iostream>
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#include <memory>
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#include <string>
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class GreeterServiceImpl final : public Greeter::Service {
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virtual grpc::Status SayHello(
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grpc::ServerContext *context,
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const flatbuffers::grpc::Message<HelloRequest> *request_msg,
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flatbuffers::grpc::Message<HelloReply> *response_msg) override {
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// flatbuffers::grpc::MessageBuilder mb_;
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// We call GetRoot to "parse" the message. Verification is already
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// performed by default. See the notes below for more details.
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const HelloRequest *request = request_msg->GetRoot();
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// Fields are retrieved as usual with FlatBuffers
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const std::string &name = request->name()->str();
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// `flatbuffers::grpc::MessageBuilder` is a `FlatBufferBuilder` with a
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// special allocator for efficient gRPC buffer transfer, but otherwise
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// usage is the same as usual.
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auto msg_offset = mb_.CreateString("Hello, " + name);
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auto hello_offset = CreateHelloReply(mb_, msg_offset);
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mb_.Finish(hello_offset);
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// The `ReleaseMessage<T>()` function detaches the message from the
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// builder, so we can transfer the resopnse to gRPC while simultaneously
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// detaching that memory buffer from the builer.
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*response_msg = mb_.ReleaseMessage<HelloReply>();
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assert(response_msg->Verify());
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// Return an OK status.
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return grpc::Status::OK;
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}
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virtual grpc::Status SayManyHellos(
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grpc::ServerContext *context,
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const flatbuffers::grpc::Message<ManyHellosRequest> *request_msg,
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grpc::ServerWriter<flatbuffers::grpc::Message<HelloReply>> *writer)
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override {
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// The streaming usage below is simply a combination of standard gRPC
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// streaming with the FlatBuffers usage shown above.
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const ManyHellosRequest *request = request_msg->GetRoot();
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const std::string &name = request->name()->str();
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int num_greetings = request->num_greetings();
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for (int i = 0; i < num_greetings; i++) {
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auto msg_offset = mb_.CreateString("Many hellos, " + name);
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auto hello_offset = CreateHelloReply(mb_, msg_offset);
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mb_.Finish(hello_offset);
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writer->Write(mb_.ReleaseMessage<HelloReply>());
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}
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return grpc::Status::OK;
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}
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flatbuffers::grpc::MessageBuilder mb_;
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};
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void RunServer() {
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std::string server_address("0.0.0.0:50051");
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GreeterServiceImpl service;
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grpc::ServerBuilder builder;
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builder.AddListeningPort(server_address, grpc::InsecureServerCredentials());
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builder.RegisterService(&service);
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std::unique_ptr<grpc::Server> server(builder.BuildAndStart());
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std::cerr << "Server listening on " << server_address << std::endl;
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server->Wait();
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}
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int main(int argc, const char *argv[]) {
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RunServer();
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return 0;
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}
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