Java gRPC拦截器简单实现分布式日志链路追踪器过程详解

    <dependencies>
        <dependency>
            <groupId>io.grpc</groupId>
            <artifactId>grpc-all</artifactId>
            <version>${grpc.version}</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>net.devh</groupId>
            <artifactId>grpc-server-spring-boot-starter</artifactId>
            <version>${grpc.starter.version}</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>net.devh</groupId>
            <artifactId>grpc-client-spring-boot-starter</artifactId>
            <version>${grpc.starter.version}</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>io.github.redick01</groupId>
            <artifactId>log-helper-spring-boot-starter-common</artifactId>
            <version>1.0.3-RELEASE</version>
        </dependency>
    </dependencies>

@Slf4j
@GrpcGlobalClientInterceptor
@GrpcGlobalServerInterceptor
public class GrpcInterceptor extends AbstractInterceptor implements ServerInterceptor, ClientInterceptor {
    // 链路追踪参数traceId
    private static final Metadata.Key<String> TRACE = Metadata.Key.of("traceId", Metadata.ASCII_STRING_MARSHALLER)
    // 链路追踪参数spanId
    private static final Metadata.Key<String> SPAN = Metadata.Key.of("spanId", Metadata.ASCII_STRING_MARSHALLER);
    // 链路追踪参数parentId
    private static final Metadata.Key<String> PARENT = Metadata.Key.of("parentId", Metadata.ASCII_STRING_MARSHALLER);
    @Override
    public <ReqT, RespT> ClientCall<ReqT, RespT> interceptCall(
            MethodDescriptor<ReqT, RespT> methodDescriptor, CallOptions callOptions,
            Channel channel) {
        StopWatch stopWatch = new StopWatch();
        stopWatch.start();
        try {
            return new ForwardingClientCall.SimpleForwardingClientCall<ReqT, RespT>(channel.newCall(methodDescriptor, callOptions)) {
                @Override
                public void start(Listener<RespT> responseListener, Metadata headers) {
                    // 客户端传递链路追中数据，将数据放到headers中
                    String traceId = traceId();
                    if (StringUtils.isNotBlank(traceId)) {
                        headers.put(TRACE, traceId);
                        headers.put(SPAN, spanId());
                        headers.put(PARENT, parentId());
                    }
                    // 继续下一步
                    super.start(new ForwardingClientCallListener.SimpleForwardingClientCallListener<RespT>(responseListener) {
                        @Override
                        public void onHeaders(Metadata headers) {
                            // 服务端传递回来的header
                            super.onHeaders(headers);
                        }
                    }, headers);
                }
            };
        } finally {
            stopWatch.stop();
            log.info(LogUtil.marker(stopWatch.getTime()), "GRPC调用耗时");
        }
    }
    @Override
    public <ReqT, RespT> Listener<ReqT> interceptCall(ServerCall<ReqT, RespT> serverCall,
            Metadata headers, ServerCallHandler<ReqT, RespT> serverCallHandler) {
        // 服务端从headers中获取到链路追踪参数
        String traceId = headers.get(TRACE);
        String spanId = headers.get(SPAN);
        String parentId = headers.get(PARENT);
        // 构建当前进程的链路追踪数据并体现在日志中
        Tracer.trace(traceId, spanId, parentId);
        log.info(LogUtil.marker(), "开始处理");
        return serverCallHandler.startCall(new ForwardingServerCall.SimpleForwardingServerCall<ReqT, RespT>(serverCall) {
            @Override
            public void sendHeaders(Metadata responseHeaders) {
                super.sendHeaders(responseHeaders);
            }
            @Override
            public void close(Status status, Metadata trailers) {
                super.close(status, trailers);
            }
        }, headers);
    }
}

@RestController
public class TestController {
    @GrpcClient("userClient")
    private UserServiceGrpc.UserServiceBlockingStub userService;
    @Autowired
    private GrpcInterceptor grpcInterceptor;
    //@LogMarker(businessDescription = "获取用户名")
    @GetMapping("/getUser")
    public String getUser()     {
        User user = User.newBuilder()
                .setUserId(100)
                .putHobbys("pingpong", "play pingpong")
                .setCode(200)
                .build();
        Channel channel = ClientInterceptors.intercept(userService.getChannel(), grpcInterceptor);
        userService = UserServiceGrpc.newBlockingStub(channel);
        User u = userService.getUser(user);
        return u.getName();
    }
}