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Auto Configuration

Dependencies​

implementation("io.github.danielliu1123:grpc-server-boot-starter")

Register Services​

After adding the dependencies, the application will start a gRPC server at 9090, and it will automatically scan and register gRPC services. You only need to add @Component based annotation to your service implementations.

@Component
public class SimpleServiceImpl extends SimpleServiceGrpc.SimpleServiceImplBase {
    @Override
    public void unaryRpc(SimpleRequest request, StreamObserver<SimpleResponse> responseObserver) {
        var response = SimpleResponse.newBuilder().setResponseMessage("Hello " + request.getRequestMessage()).build();
        responseObserver.onNext(response);
        responseObserver.onCompleted();
    }
}
info

The framework provides a @GrpcService annotation to better distinguish bean types. But it is not necessary, you can use Spring's built-in @Component/@Service/@Controller instead.

In-process Server​

gRPC server supports in-process transport, which is useful for testing scenarios.

grpc:
  server:
    in-process:
      name: whatever

Build-in Services​

io.grpc:grpc-services provides a series of built-in services.

Health​

Health service is enabled by default.

Use the following configuration to disable it:

grpc:
  server:
    health:
      enabled: false

You can customize the health check logic by implementing the HealthChecker interface.

There are some build-in HealthChecker implementations:

Use the following configuration to disable them:

grpc:
  server:
    health:
      datasource:
        enabled: false
      redis:
        enabled: false

Starting from version 3.4.0, to better support Kubernetes Probes, three special services were introduced: startup, readiness, and liveness.

For startup and readiness, the system will return the SERVING status only when all HealthCheckers pass their checks (return true), as they rely on the state of external services.

For liveness, it always returns the SERVING status, as it does not rely on the state of external services.

This is suitable for most applications. If you need more customization, you can implement the health service yourself:

@Component
public class HealthService extends HealthGrpc.HealthImplBase {
    @Override
    public void check(HealthCheckRequest request, StreamObserver<HealthCheckResponse> responseObserver) {
        // Your custom health check logic
        var result = HealthCheckResponse.ServingStatus.SERVING;
        responseObserver.onNext(
                HealthCheckResponse.newBuilder().setStatus(result).build());
        responseObserver.onCompleted();
    }
}

Reflection​

Reflection is disabled by default, it's often used in development and debugging scenarios.

Use the following configuration to enable it:

grpc:
  server:
    reflection:
      enabled: true

Channelz​

Channelz is disabled by default.

Use the following configuration to enable it:

grpc:
  server:
    channelz:
      enabled: true

Virtual Threads Support​

Starting from version 3.5.3.2, gRPC server supports virtual threads when using Java 21+.

When spring.threads.virtual.enabled is set to true, the gRPC server will automatically use virtual threads to handle requests, providing better performance for I/O-bound operations.

spring:
  threads:
    virtual:
      enabled: true
info

Virtual threads are only available in Java 21+. This feature will be ignored on older Java versions.

Configurations​

Full configuration is available in the GrpcServerProperties.