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gRPC with Quarkus!

In Quarkus 1.5, we shipped the first version of the gRPC Quarkus extension.

If you are not familiar with gRPC, it’s a highly efficient Remote Procedure Call mechanism relying on HTTP/2 and Protobuf. You can implement and consume gRPC services from any language such as Go, JavaScript, Python, and Java. gRPC supports bi-directional streams of data as well as the more classical request-reply interation scheme. gRPC is particularly well suited for microservices. It provides support for authentication, tracing, and health, 3 major concerns when building microservice systems.

gRPC services are described in proto files listing the different methods (Hello in the following example) and defining the exchanged messages (HelloRequest and HelloReply):

syntax = "proto3";

option java_multiple_files = true;
option java_package = "io.quarkus.grpc.examples.helloworld";
option java_outer_classname = "HelloWorld";

package io.quarkus.grpc.example;

service Greeter {
    rpc Hello (HelloRequest) returns (HelloReply) {}
}

message HelloRequest {
    string name = 1;
}

message HelloReply {
    string message = 1;
}

protoc, the Proto Compiler, generates the stub (client) and base implementations (service) from these proto files for the different targetted languages:

Protoc generation

To enable the gRPC support in Quarkus, add the quarkus-grpc extension. You can do that by adding the following dependency to your project or run the following command.

The quarkus-grpc dependency
<dependency>
  <groupId>io.quarkus</groupId>
  <artifactId>quarkus-grpc</artifactId>
</dependency>
Add the quarkus-grpc extension to an existing project
mvn quarkus:add-extension -Dextension=quarkus-grpc

Of course, you can also select gRPC from the project generator.

At the moment, the extension does not cover the protoc generation, and you need to configure your project to do so. You can find an example here.

The gRPC extension supports:

  • implementing gRPC services

  • consuming of gRPC services

  • plain-text and TLS

  • mutual authentication

  • the gRPC health and reflection services

  • the gRPC "bare" Java API and a Mutiny API that integrates with the reactive APIS from Quarkus.

Enough blabla, time to see it in action:

The code shown in this video is available from this GitHub project.

More to come!

That’s just the first step. We have plenty of ideas to make it better. First, we want to cover the protoc generation and improve the hot-reload experience by allowing modifying these proto files at development time. The support of custom compressors, load-balancers, and name resolvers are also on the roadmap.

We value your feedback a lot so please report bugs, ask for improvements…​

If you are a Quarkus user or just curious, don’t be shy and join our community: