grpc

Background

gRPC is a modern, open source, high-performance remote procedure call (RPC) framework that can run anywhere. gRPC enables client and server applications to communicate transparently, and simplifies the building of connected systems.

gRPC was released right around the time I started at CTC, and I have yet to actually use the technology. Additionally, flatbuffers has recently added gRPC support and I had a long weekend to kill ...

Asynchronous Example

The C++ flatbuffer gRPC example follows the protobuf documentation and demonstrates how to implement a single-threaded RPC client / server. The protobuf examples extend this with async client and server, however the flatbuffer examples neglect to include these... I (think) I was able to figure out how to do the asynchronous bits using flatbuffers. (I should submit a PR...)

Building

As with the other more recent repositiories up here I'm using the VS Code Docker integration for my development. Look at the .devcontainer/Dockerfile for the project dependencies if you want to roll your own.

git clone git@github.com:mattygiedt/grpc.git
cd grpc
code . <open project inside dev container>
mkdir build
cd build
cmake ..
make -j4

Client / Server

Split your Terminal in half, and then start-up the server ...

root@:/workspaces/grpc/build# ./src/cpp/server 0.0.0.0:50051
[2022-09-06 23:21:54.486] [info] Server listening on 0.0.0.0:50051

And then play around with the client.

root@:/workspaces/grpc/build# ./src/cpp/client localhost:50051
[2022-09-06 23:22:19.095] [info] server addr: localhost:50051
[2022-09-06 23:22:19.098] [info] SayHello request: World, response: Hello, World
[2022-09-06 23:22:19.098] [info] SayManyHellos received: Many hellos, World
[2022-09-06 23:22:19.098] [info] SayManyHellos received: Many hellos, World
[2022-09-06 23:22:19.098] [info] SayManyHellos received: Many hellos, World
[2022-09-06 23:22:19.098] [info] SayManyHellos received: Many hellos, World
[2022-09-06 23:22:19.098] [info] SayManyHellos received: Many hellos, World
[2022-09-06 23:22:19.098] [info] SayManyHellos received: Many hellos, World
[2022-09-06 23:22:19.098] [info] SayManyHellos received: Many hellos, World
[2022-09-06 23:22:19.098] [info] SayManyHellos received: Many hellos, World
[2022-09-06 23:22:19.099] [info] SayManyHellos received: Many hellos, World
[2022-09-06 23:22:19.099] [info] SayManyHellos received: Many hellos, World
root@:/workspaces/grpc/build#

Asynchronous Client / Server

Start the server first:

root@:/workspaces/grpc/build# ./src/cpp/async_server 0.0.0.0:50051
[2022-09-06 23:24:59.129] [info] Server listening on 0.0.0.0:50051

And then connect the client:

root@:/workspaces/grpc/build# ./src/cpp/async_client localhost:50051
[2022-09-06 23:25:21.035] [info] server addr: localhost:50051
[2022-09-06 23:25:21.037] [info] SayHelloAsync request: World, response: Hello, World

Last thoughts

I fully recognize that this is just a small drop in the gRPC ocean. There is a lot more to learn within gRPC. For instance, I'd like to spend some more time on the streaming capabilities. Which feels odd -- why would I want an RPC framework providing me PUB / SUB?

Anyway, I continue to be a big fan of flatbuffers and now have at least of modicum of experience with gRPC!