This version is still in development and is not considered stable yet. For the latest stable version, please use Spring Cloud Gateway 4.2.0!

JsonToGrpc GatewayFilter Factory

The JSONToGRPC GatewayFilter Factory converts a JSON payload to a gRPC request.

The filter takes the following arguments:

  • protoDescriptor: Proto descriptor file.

This file can be generated using protoc and specifying the --descriptor_set_out flag:

protoc --proto_path=src/main/resources/proto/ \
--descriptor_set_out=src/main/resources/proto/hello.pb  \
src/main/resources/proto/hello.proto

  • protoFile: Proto definition file.

  • service: Short name of the service that handles the request.

  • method: Method name in the service that handles the request.

streaming is not supported.

application.yml.

@Bean
public RouteLocator routes(RouteLocatorBuilder builder) {
    return builder.routes()
            .route("json-grpc", r -> r.path("/json/hello").filters(f -> {
                String protoDescriptor = "file:src/main/proto/hello.pb";
                String protoFile = "file:src/main/proto/hello.proto";
                String service = "HelloService";
                String method = "hello";
                return f.jsonToGRPC(protoDescriptor, protoFile, service, method);
            }).uri(uri))
spring:
  cloud:
    gateway:
      routes:
        - id: json-grpc
          uri: https://localhost:6565/testhello
          predicates:
            - Path=/json/**
          filters:
            - name: JsonToGrpc
              args:
                protoDescriptor: file:proto/hello.pb
                protoFile: file:proto/hello.proto
                service: HelloService
                method: hello

When a request is made through the gateway to /json/hello, the request is transformed by using the definition provided in hello.proto, sent to HelloService/hello, and the response back is transformed to JSON.

By default, it creates a NettyChannel by using the default TrustManagerFactory. However, you can customize this TrustManager by creating a bean of type GrpcSslConfigurer:

@Configuration
public class GRPCLocalConfiguration {
    @Bean
    public GRPCSSLContext sslContext() {
		TrustManager trustManager = trustAllCerts();
        return new GRPCSSLContext(trustManager);
    }
}