grpc-server.java

import com.google.rpc.Status;
import io.envoyproxy.envoy.service.auth.v2.AuthorizationGrpc;
import io.envoyproxy.envoy.service.auth.v2.CheckRequest;
import io.envoyproxy.envoy.service.auth.v2.CheckResponse;
import io.envoyproxy.envoy.service.auth.v2.DeniedHttpResponse;
import io.envoyproxy.envoy.type.HttpStatus;
import io.envoyproxy.envoy.type.StatusCode;
import io.grpc.Server;
import io.grpc.ServerBuilder;
import io.grpc.stub.StreamObserver;

import java.io.IOException;
import java.util.Map;

public class AuthServerGrpc {

    private Server server;

    private void start() throws IOException {
        int port = 3333;
        server = ServerBuilder.forPort(port)
                .addService(new AuthService())
                .build()
                .start();
        System.out.println("AuthServerGrpc started, listening on " + port);
        Runtime.getRuntime().addShutdownHook(new Thread() {
            @Override
            public void run() {
                // Use stderr here since the logger may have been reset by its JVM shutdown hook.
                System.err.println("*** shutting down gRPC server since JVM is shutting down");
                AuthServerGrpc.this.stop();
                System.err.println("*** server shut down");
            }
        });
    }

    private void stop() {
        if (server != null) {
            server.shutdown();
        }
    }

    private void blockUntilShutdown() throws InterruptedException {
        if (server != null) {
            server.awaitTermination();
        }
    }

    public static void main(String[] args) throws Exception {
        final AuthServerGrpc server = new AuthServerGrpc();
        server.start();
        server.blockUntilShutdown();
    }

    static class AuthService extends AuthorizationGrpc.AuthorizationImplBase {
        @Override
        public void check(CheckRequest request, StreamObserver<CheckResponse> responseObserver) {
            Map<String, String> headers = request.getAttributes().getRequest().getHttp().getHeadersMap();
            if (headers.containsKey("authorization")) {
                CheckResponse checkResponse = CheckResponse.newBuilder().build();
                responseObserver.onNext(checkResponse);
                responseObserver.onCompleted();
            } else {
                CheckResponse checkResponse = CheckResponse.newBuilder()
                        .setDeniedResponse(DeniedHttpResponse.newBuilder()
                                .setStatus(HttpStatus.newBuilder().setCode(StatusCode.Unauthorized).build())
                                .setBody("not allowed")
                                .build())
                        .setStatus(Status.newBuilder().setCode(StatusCode.Unauthorized_VALUE).build()).build();
                responseObserver.onNext(checkResponse);
                responseObserver.onCompleted();
            }
        }
    }

}