In a microservices architecture, gRPC can be used to allow microservices to communicate with each other efficiently and securely.
Each microservice can implement a gRPC server that exposes a set of methods that can be called by other microservices.
The methods can be defined in a Protocol Buffer service definition file, which specifies the input and output types for each method.
The microservices can then use a gRPC client to call the methods exposed by other microservices.
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public class ProductService extends ProductServiceGrpc.ProductServiceImplBase {
private final ProductRepository productRepository;
public ProductService() {
this.productRepository = new ProductRepository();
}
@Override
public void getProduct(
GetProductRequest request, StreamObserver<GetProductResponse> responseObserver) {
var productId = request.getProductId();
Optional<ProductInfo> productInfo = productRepository.get(productId);
if (productInfo.isPresent()) {
var product = productInfo.get();
var getProductResponse =
GetProductResponse.newBuilder()
.setName(product.getName())
.setDescription(product.getDescription())
.setPrice(product.getPrice())
.build();
responseObserver.onNext(getProductResponse);
responseObserver.onCompleted();
} else {
responseObserver.onError(new StatusException(Status.NOT_FOUND));
}
}
}