harendra247 / grpc-examples

gRPC c++ examples with cmake

grpc-examples

gRPC c++ examples with CMake.

C++ Installation

How To Install

Linux:

[sudo] apt-get install build-essential autoconf libtool pkg-config cmake
wget -O v1.48.0.tar.gz https://github.com/grpc/grpc/archive/refs/tags/v1.48.0.tar.gz
tar -xzvf v1.48.0.tar.gz
cd grpc-1.48.0
mkdir -p cmake/build
cd cmake/build
cmake ../..
make
sudo make install

Dependencies

• gRPC 1.48.0
• CMake 3.15.0+

Files

.
|-- CMakeLists.txt
|-- LICENSE
|-- README.md
|-- docker
|   `-- grpc.Dockerfile
|-- protos
|   |-- calculator.proto
|   |-- greetings.proto
|   |-- route_guide.proto
|   `-- sample_grpc.proto
|-- runtime.sh
`-- src
    |-- CMakeLists.txt
    |-- Makefile
    |-- calculator
    |   |-- CMakeLists.txt
    |   |-- calculator_async_client.cpp
    |   |-- calculator_async_server.cpp
    |   |-- calculator_client.cpp
    |   `-- calculator_server.cpp
    |-- greetings
    |   |-- CMakeLists.txt
    |   |-- greetings_client.cpp
    |   `-- greetings_server.cpp
    `-- sample_grpc
        |-- CMakeLists.txt
        |-- sample_grpc_async_client.cpp
        |-- sample_grpc_async_server.cpp
        |-- sample_grpc_client.cpp
        `-- sample_grpc_server.cpp

Working with Examples

How to define a service

Instruction

Define a service in a .proto file using the Interface Definition Language (IDL) from Protocol Buffers.

Example: Hello World service

syntax = "proto3";

option java_package = "sample_grpc.grpc";

package sample_grpc;

service SampleGRPCService {
    rpc Method (Request) returns (Response) {}
}

message Request {
    string request_field = 1;
}

message Response {
    string response_field = 1;
}

Example: Calculator service

Example: Greetings service

Note

How to generate gRPC code

Instruction

Use the protocol buffer compiler protoc to generate client and server code:

$ protoc -I=$SRC_DIR --cpp_out=$DST_DIR $SRC_DIR/sample_grpc.proto
$ protoc -I=$SRC_DIR --grpc_out=$DST_DIR --plugin=protoc-gen-grpc=/usr/local/bin/grpc_cpp_plugin $SRC_DIR/sample_grpc.proto

where:

• SRC_DIR: The source directory, or the directory contains the .proto file.
• DST_DIR: The destination directory, or the directory contains the .pb.h, .pb.cc, .grpc.pb.h and .grpc.pb.cc files.

Example: Hello World

With SRC_DIR = protos/ and DST_DIR = sample_grpc/:

$ protoc -I=protos/ --cpp_out=sample_grpc/ protos/sample_grpc.proto
$ protoc -I=protos/ --grpc_out=sample_grpc/ --plugin=protoc-gen-grpc=/usr/local/bin/grpc_cpp_plugin protos/sample_grpc.proto

Example: Calculator

With SRC_DIR = protos/ and DST_DIR = calculator/:

$ protoc -I=protos/ --cpp_out=calculator/ protos/calculator.proto
$ protoc -I=protos/ --grpc_out=calculator/ --plugin=protoc-gen-grpc=/usr/local/bin/grpc_cpp_plugin protos/calculator.proto

Note

The .pb.h, .pb.cc, .grpc.pb.h and .grpc.pb.cc files could be generated automatically by the CMake's add_custom_command command and should not be included in the actual project. See also: Hello World CMakeLists.txt, Calculator CMakeLists.txt and Greetings CMakeLists.txt.

How to write a client

Instruction

1. Create a channel.
2. Create a stub.
3. Make a unary RPC.
4. Check returned status and response.

Example: Hello World client

Example: Calculator client

Example: Greetings client

Note

How to write a server

Instruction

1. Implement the service interface.
2. Build a server exporting the service.

Example: Hello World server

Example: Calculator server

Example: Greetings server

Note

How to write an async client

Instruction

1. Create a channel.
2. Create a stub.
3. Initiate the RPC and bind it to a CompletionQueue.
4. Request to update the response and the call status upon completion of the RPC with a unique tag.
5. Wait for the completion queue to return the next tag.

Example: Hello World async client

Example: Calculator async client

Note

How to write an async server

Instruction

1. Build a server exporting the async service.
2. Request an RPC with a unique tag.
3. Wait for the completion queue to return the next tag.

Example: Hello World async server

Example: Calculator async server

Note

Usages

Build Docker Image

$ docker build -f docker/grpc.Dockerfile --build-arg GPRC_VERSION=1.44.0 --build-arg NUM_JOBS=8 --tag grpc-examples:1.44.0 .

To build for different gRPC versions and use different number of CPU threads, please pass values accordingly.

Run Docker Container

Docker container should be started for the gRPC server and the gRPC client.

$ docker container run --network host --rm --mount src=`pwd`,target=/root/examples,type=bind -it grpc-examples:1.44.0 /bin/bash

Build Examples

$ cmake -B build
$ cmake --build build --config Release --parallel 8

All the executable files would be generated in build directory.

Run Examples

Calculator

In one terminal, we start the gRPC server.

$ ./build/src/calculator/calculator_server
Server listening on 0.0.0.0:2510

In another terminal, we start the gRPC client.

$ ./build/src/calculator/calculator_client 
25 + 10 = 35
25 - 10 = 15
25 * 10 = 250
25 / 10 = 2
25 % 10 = 5

Greetings Server

In one terminal, we start the gRPC server.

$ ./build/src/greetings/greetings_server 
Server listening on 0.0.0.0:50051

In another terminal, we start the gRPC client.

$ ./build/src/greetings/greetings_client 
Please enter your user name:
harendra
gRPC returned: 
Hello harendra!
Please enter your user name:
hsingh
gRPC returned: 
Hello hsingh!
Please enter your user name:

Hello World

In one terminal, we start the gRPC server.

$ ./build/src/sample_grpc/sample_grpc_server 
Server listening on 0.0.0.0:2510

In another terminal, we start the gRPC client.

$ ./build/src/sample_grpc/sample_grpc_client 
Client received: Hello world

References