brew install protobuf swift-protobuf grpc-swift

git clone --depth 1 --filter=blob:none --sparse https://github.com/grpc/grpc
cd grpc && git sparse-checkout set examples

cd grpc/examples/python/helloworld/
python3 -m pip install grpcio grpcio-tools grpcio-reflection
python3 greeter_server_with_reflection.py

grpc/examples/protos/helloworld.proto

cd grpc/examples/protos/

protoc --swift_out=. --grpc-swift_out=Client=true,Server=false:. helloworld.proto

Import to Xcode files:

• helloworld.grpc.swift
• helloworld.pb.swift

File->Swift Packages->Add Package Dependency
https://github.com/grpc/grpc-swift

Add GRPC to your target

import GRPC
import NIO

        let conf = ClientConnection.Configuration.default(
            target:.hostAndPort("localhost", 50051),
            eventLoopGroup: MultiThreadedEventLoopGroup(numberOfThreads: 1))
        
        let connection: ClientConnection = ClientConnection.init(configuration: conf)
        
        let helloRequest = Helloworld_HelloRequest.with {
            $0.name = "SwiftUI"
        }
        
        let client = Helloworld_GreeterNIOClient(channel: connection)
        
        _ = client.sayHello(helloRequest).response.always { result in
            switch result {
            case let .success(helloResponse):
                print(helloResponse.message)
            case let .failure(error):
                print(error)
            }
        }