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gRPCサービスの実装

gRPC service implementations exposed as CDI beans are automatically registered and served by quarkus-grpc.

gRPC サービスを実装するには、gRPC クラスを生成する必要があります。 proto ファイルを src/main/proto に置き、 mvn compile を実行します。

Generated Code

Quarkus generates a few implementation classes for services declared in the proto file:

  1. A service interface using the Mutiny API

    • the class name is ${JAVA_PACKAGE}.${NAME_OF_THE_SERVICE}

  2. An implementation base class using the gRPC API

    • the class name is structured as follows: ${JAVA_PACKAGE}.${NAME_OF_THE_SERVICE}Grpc.${NAME_OF_THE_SERVICE}ImplBase

For example, if you use the following proto file snippet:

option java_package = "hello"; (1)

service Greeter { (2)
    rpc SayHello (HelloRequest) returns (HelloReply) {}
}
1 hello is the java package for the generated classes.
2 Greeter is the service name.

Then the service interface is hello.Greeter and the implementation base is the abstract static nested class: hello.GreeterGrpc.GreeterImplBase.

You’ll need to implement the service interface or extend the base class with your service implementation bean as described in the following sections.

Implementing a Service with the Mutiny API

To implement a gRPC service using the Mutiny API, create a class that implements the service interface. Then, implement the methods defined in the service interface. If you don’t want to implement a service method just throw an java.lang.UnsupportedOperationException from the method body (the exception will be automatically converted to the appropriate gRPC exception). Finally, implement the service and add the @GrpcService annotation:

import io.quarkus.grpc.GrpcService;
import hello.Greeter;

@GrpcService (1)
public class HelloService implements Greeter { (2)

    @Override
    public Uni<HelloReply> sayHello(HelloRequest request) {
        return Uni.createFrom().item(() ->
                HelloReply.newBuilder().setMessage("Hello " + request.getName()).build()
        );
    }
}
1 A gRPC service implementation bean must be annotated with the @GrpcService annotation and should not declare any other CDI qualifier. All gRPC services have the javax.inject.Singleton scope. Additionally, the request context is always active during a service call.
2 hello.Greeter is the generated service interface.
The service implementation bean can also extend the Mutiny implementation base, where the class name is structured as follows: Mutiny${NAME_OF_THE_SERVICE}Grpc.${NAME_OF_THE_SERVICE}ImplBase.

Implementing a Service with the default gRPC API

To implement a gRPC service using the default gRPC API, create a class that extends the default implementation base. Then, override the methods defined in the service interface. Finally, implement the service and add the @GrpcService annotation:

import io.quarkus.grpc.GrpcService;

@GrpcService
public class HelloService extends GreeterGrpc.GreeterImplBase {

    @Override
    public void sayHello(HelloRequest request, StreamObserver<HelloReply> responseObserver) {
        String name = request.getName();
        String message = "Hello " + name;
        responseObserver.onNext(HelloReply.newBuilder().setMessage(message).build());
        responseObserver.onCompleted();
    }
}

Blocking Service Implementation

デフォルトでは、gRPCサービスからのすべてのメソッドはイベントループ上で実行されます。そのため、ブロックしては いけません 。サービスロジックをブロックする必要がある場合は、メソッドに io.smallrye.common.annotation.Blocking アノテーションを追加します。

@Override
@Blocking
public Uni<HelloReply> sayHelloBlocking(HelloRequest request) {
    // Do something blocking before returning the Uni
}

Handling Streams

gRPCでは、ストリームを受信して返すことができます。

service Streaming {
    rpc Source(Empty) returns (stream Item) {} // Returns a stream
    rpc Sink(stream Item) returns (Empty) {}   // Reads a stream
    rpc Pipe(stream Item) returns (stream Item) {}  // Reads a streams and return a streams
}

Mutinyを使うと、以下のように実装できます。

import io.quarkus.grpc.GrpcService;

@GrpcService
public class StreamingService implements Streaming {

    @Override
    public Multi<Item> source(Empty request) {
        // Just returns a stream emitting an item every 2ms and stopping after 10 items.
        return Multi.createFrom().ticks().every(Duration.ofMillis(2))
                .select().first(10)
                .map(l -> Item.newBuilder().setValue(Long.toString(l)).build());
    }

    @Override
    public Uni<Empty> sink(Multi<Item> request) {
        // Reads the incoming streams, consume all the items.
        return request
                .map(Item::getValue)
                .map(Long::parseLong)
                .collect().last()
                .map(l -> Empty.newBuilder().build());
    }

    @Override
    public Multi<Item> pipe(Multi<Item> request) {
        // Reads the incoming stream, compute a sum and return the cumulative results
        // in the outbound stream.
        return request
                .map(Item::getValue)
                .map(Long::parseLong)
                .onItem().scan(() -> 0L, Long::sum)
                .onItem().transform(l -> Item.newBuilder().setValue(Long.toString(l)).build());
    }
}

Health Check

実装されたサービスでは、Quarkus gRPCは以下の形式でヘルスチェックを公開しています。

syntax = "proto3";

package grpc.health.v1;

message HealthCheckRequest {
  string service = 1;
}

message HealthCheckResponse {
  enum ServingStatus {
    UNKNOWN = 0;
    SERVING = 1;
    NOT_SERVING = 2;
  }
  ServingStatus status = 1;
}

service Health {
  rpc Check(HealthCheckRequest) returns (HealthCheckResponse);

  rpc Watch(HealthCheckRequest) returns (stream HealthCheckResponse);
}

クライアントは、特定のサービスのヘルス状態を取得するために完全修飾されたサービス名を指定したり、gRPCサーバーの一般的な状態を取得するためにサービス名の指定を省略することができます。

詳細については、 gRPCのドキュメント を確認してください。

さらに、Quarkus SmallRye Healthがアプリケーションに追加された場合、gRPCサービスの状態に関するレディネスチェックがMicroProfile Healthエンドポイントレスポンスに追加されます( /q/health )。

リフレクションサービス

Quarkus gRPC Serverは、 リフレクションサービス を実装しています。このサービスを使用すると、 grpcurlgrpcox などのツールがサービスと対話できるようになります。

リフレクションサービスは、 開発 モードではデフォルトで有効になっています。テストモードやプロダクションモードでは、 quarkus.grpc.server.enable-reflection-servicetrue に設定して明示的に有効にする必要があります。

スケーリング

デフォルトでは、quarkus-grpcは単一のイベントループ上で動作する単一のgRPCサーバーを起動します。

サーバーをスケールさせたい場合は、 quarkus.grpc.server.instances を設定することで、サーバーのインスタンス数をセットできます。

Server Configuration

ビルド時に固定される設定プロパティ - それ以外の設定プロパティは実行時に上書き可能

Configure the gRPC server

タイプ

デフォルト

The gRPC Server port.

Environment variable: QUARKUS_GRPC_SERVER_PORT

int

9000

The gRPC Server port used for tests.

Environment variable: QUARKUS_GRPC_SERVER_TEST_PORT

int

9001

The gRPC server host.

Environment variable: QUARKUS_GRPC_SERVER_HOST

string

0.0.0.0

The gRPC handshake timeout.

Environment variable: QUARKUS_GRPC_SERVER_HANDSHAKE_TIMEOUT

Duration

The max inbound message size in bytes.

Environment variable: QUARKUS_GRPC_SERVER_MAX_INBOUND_MESSAGE_SIZE

int

The max inbound metadata size in bytes

Environment variable: QUARKUS_GRPC_SERVER_MAX_INBOUND_METADATA_SIZE

int

The classpath path or file path to a server certificate or certificate chain in PEM format.

Environment variable: QUARKUS_GRPC_SERVER_SSL_CERTIFICATE

path

The classpath path or file path to the corresponding certificate private key file in PEM format.

Environment variable: QUARKUS_GRPC_SERVER_SSL_KEY

path

An optional key store which holds the certificate information instead of specifying separate files. The key store can be either on classpath or an external file.

Environment variable: QUARKUS_GRPC_SERVER_SSL_KEY_STORE

path

An optional parameter to specify the type of the key store file. If not given, the type is automatically detected based on the file name.

Environment variable: QUARKUS_GRPC_SERVER_SSL_KEY_STORE_TYPE

string

A parameter to specify the password of the key store file. If not given, the default ("password") is used.

Environment variable: QUARKUS_GRPC_SERVER_SSL_KEY_STORE_PASSWORD

string

password

An optional trust store which holds the certificate information of the certificates to trust The trust store can be either on classpath or an external file.

Environment variable: QUARKUS_GRPC_SERVER_SSL_TRUST_STORE

path

An optional parameter to specify type of the trust store file. If not given, the type is automatically detected based on the file name.

Environment variable: QUARKUS_GRPC_SERVER_SSL_TRUST_STORE_TYPE

string

A parameter to specify the password of the trust store file.

Environment variable: QUARKUS_GRPC_SERVER_SSL_TRUST_STORE_PASSWORD

string

The cipher suites to use. If none is given, a reasonable default is selected.

Environment variable: QUARKUS_GRPC_SERVER_SSL_CIPHER_SUITES

list of string

The list of protocols to explicitly enable.

Environment variable: QUARKUS_GRPC_SERVER_SSL_PROTOCOLS

list of string

TLSv1.3,TLSv1.2

Configures the engine to require/request client authentication. NONE, REQUEST, REQUIRED

Environment variable: QUARKUS_GRPC_SERVER_SSL_CLIENT_AUTH

none, request, required

none

Disables SSL, and uses plain text instead. If disabled, configure the ssl configuration.

Environment variable: QUARKUS_GRPC_SERVER_PLAIN_TEXT

boolean

true

Whether ALPN should be used.

Environment variable: QUARKUS_GRPC_SERVER_ALPN

boolean

true

The path to the certificate file.

Environment variable: QUARKUS_GRPC_SERVER_TRANSPORT_SECURITY_CERTIFICATE

string

The path to the private key file.

Environment variable: QUARKUS_GRPC_SERVER_TRANSPORT_SECURITY_KEY

string

Enables the gRPC Reflection Service. By default, the reflection service is only exposed in dev mode. This setting allows overriding this choice and enable the reflection service every time.

Environment variable: QUARKUS_GRPC_SERVER_ENABLE_REFLECTION_SERVICE

boolean

false

Number of gRPC server verticle instances. This is useful for scaling easily across multiple cores. The number should not exceed the amount of event loops.

Environment variable: QUARKUS_GRPC_SERVER_INSTANCES

int

1

Sets a custom keep-alive duration. This configures the time before sending a keepalive ping when there is no read activity.

Environment variable: QUARKUS_GRPC_SERVER_NETTY_KEEP_ALIVE_TIME

Duration

gRPC compression, e.g. "gzip"

Environment variable: QUARKUS_GRPC_SERVER_COMPRESSION

string

期間フォーマットについて

期間のフォーマットは標準の java.time.Duration フォーマットを使用します。詳細は Duration#parse() javadoc を参照してください。

数値で始まる期間の値を指定することもできます。この場合、値が数値のみで構成されている場合、コンバーターは値を秒として扱います。そうでない場合は、 PT が暗黙的に値の前に付加され、標準の java.time.Duration 形式が得られます。

Example of Configuration

TLSを有効にする

TLSを有効にするには、以下の設定を使用します。

設定のすべてのパスは、クラスパス上のリソース (通常は src/main/resources やそのサブフォルダーから) か外部ファイルを指定することに注意してください。

quarkus.grpc.server.ssl.certificate=tls/server.pem
quarkus.grpc.server.ssl.key=tls/server.key
SSL/TLSを設定すると、 plain-text は自動的に無効になります。

相互認証付きTLS

相互認証付きのTLSを使用するには、以下の設定を使用します。

quarkus.grpc.server.ssl.certificate=tls/server.pem
quarkus.grpc.server.ssl.key=tls/server.key
quarkus.grpc.server.ssl.trust-store=tls/ca.jks
quarkus.grpc.server.ssl.trust-store-password=*****
quarkus.grpc.server.ssl.client-auth=REQUIRED

サーバーインターセプター

gRPC server interceptors let you perform logic, such as authentication, before your service is invoked.

You can implement a gRPC server interceptor by creating an @ApplicationScoped bean implementing io.grpc.ServerInterceptor:

@ApplicationScoped
// add @GlobalInterceptor for interceptors meant to be invoked for every service
public class MyInterceptor implements ServerInterceptor {

    @Override
    public <ReqT, RespT> ServerCall.Listener<ReqT> interceptCall(ServerCall<ReqT, RespT> serverCall,
            Metadata metadata, ServerCallHandler<ReqT, RespT> serverCallHandler) {
        // ...
    }
}
ServerInterceptor JavaDoc をチェックして、インターセプターを適切に実装してください。

To apply an interceptor to all exposed services, annotate it with @io.quarkus.grpc.GlobalInterceptor. To apply an interceptor to a single service, register it on the service with @io.quarkus.grpc.RegisterInterceptor:

import io.quarkus.grpc.GrpcService;
import io.quarkus.grpc.RegisterInterceptor;

@GrpcService
@RegisterInterceptor(MyInterceptor.class)
public class StreamingService implements Streaming {
    // ...
}

When you have multiple server interceptors, you can order them by implementing the javax.enterprise.inject.spi.Prioritized interface. Please note that all the global interceptors are invoked before the service-specific interceptors.

@ApplicationScoped
public class MyInterceptor implements ServerInterceptor, Prioritized {

    @Override
    public <ReqT, RespT> ServerCall.Listener<ReqT> interceptCall(ServerCall<ReqT, RespT> serverCall,
            Metadata metadata, ServerCallHandler<ReqT, RespT> serverCallHandler) {
        // ...
    }

    @Override
    public int getPriority() {
        return 10;
    }
}

最高の優先度を持つインターセプターが最初に呼び出されます。インターセプターが Prioritized インターフェイスを実装していない場合に使用されるデフォルトの優先度は 0 です。

Testing your services

The easiest way to test a gRPC service is to use a gRPC client as described in Consuming a gRPC Service.

Please note that in the case of using a client to test an exposed service that does not use TLS, there is no need to provide any configuration. E.g. to test the HelloService defined above, one could create the following test:

public class HelloServiceTest implements Greeter {

    @GrpcClient
    Greeter client;

    @Test
    void shouldReturnHello() {
        CompletableFuture<String> message = new CompletableFuture<>();
        client.sayHello(HelloRequest.newBuilder().setName("Quarkus").build())
                .subscribe().with(reply -> message.complete(reply.getMessage()));
        assertThat(message.get(5, TimeUnit.SECONDS)).isEqualTo("Hello Quarkus");
    }
}

Trying out your services manually

In the dev mode, you can try out your gRPC services in the Quarkus Dev UI. Just go to http://localhost:8080/q/dev and click on Services under the gRPC tile.

Please note that your application needs to expose the "normal" HTTP port for the Dev UI to be accessible. If your application does not expose any HTTP endpoints, you can create a dedicated profile with a dependency on quarkus-vertx-http:

    <profiles>
        <profile>
            <id>development</id>
            <dependencies>
                <dependency>
                    <groupId>io.quarkus</groupId>
                    <artifactId>quarkus-vertx-http</artifactId>
                </dependency>
            </dependencies>
        </profiles>
    </profile>

Having it, you can run the dev mode with: mvn quarkus:dev -Pdevelopment.

If you use Gradle, you can simply add a dependency for the quarkusDev task:

dependencies {
    quarkusDev 'io.quarkus:quarkus-vertx-http'
}

gRPC Server metrics

Enabling metrics collection

gRPC server metrics are automatically enabled when the application also uses the quarkus-micrometer extension. Micrometer collects the metrics of all the gRPC services implemented by the application.

As an example, if you export the metrics to Prometheus, you will get:

# HELP grpc_server_responses_sent_messages_total The total number of responses sent
# TYPE grpc_server_responses_sent_messages_total counter
grpc_server_responses_sent_messages_total{method="SayHello",methodType="UNARY",service="helloworld.Greeter",} 6.0
# HELP grpc_server_processing_duration_seconds The total time taken for the server to complete the call
# TYPE grpc_server_processing_duration_seconds summary
grpc_server_processing_duration_seconds_count{method="SayHello",methodType="UNARY",service="helloworld.Greeter",statusCode="OK",} 6.0
grpc_server_processing_duration_seconds_sum{method="SayHello",methodType="UNARY",service="helloworld.Greeter",statusCode="OK",} 0.016216771
# HELP grpc_server_processing_duration_seconds_max The total time taken for the server to complete the call
# TYPE grpc_server_processing_duration_seconds_max gauge
grpc_server_processing_duration_seconds_max{method="SayHello",methodType="UNARY",service="helloworld.Greeter",statusCode="OK",} 0.007985236
# HELP grpc_server_requests_received_messages_total The total number of requests received
# TYPE grpc_server_requests_received_messages_total counter
grpc_server_requests_received_messages_total{method="SayHello",methodType="UNARY",service="helloworld.Greeter",} 6.0

The service name, method and type can be found in the tags.

Disabling metrics collection

To disable the gRPC server metrics when quarkus-micrometer is used, add the following property to the application configuration:

quarkus.micrometer.binder.grpc-server.enabled=false