Implementation:Apache Dolphinscheduler NettyRemotingClient SendSync

Knowledge Sources	Apache DolphinScheduler Netty Framework
Domains	Distributed_Systems, RPC
Last Updated	2026-02-10 00:00 GMT

Overview

Concrete tool for executing synchronous RPC calls using NettyRemotingClient.sendSync() with Transporter wire protocol and ResponseFuture blocking.

Description

NettyRemotingClient manages Netty channels to remote servers and provides sendSync() for blocking RPC calls. It maintains a channel cache per host, automatically reconnecting on channel inactivity. The sendSync() method creates a ResponseFuture, sends the Transporter message via the channel, and blocks until the response arrives. SyncClientMethodInvoker bridges the proxy invocation to sendSync().

Usage

Used internally by ClientInvocationHandler when a proxy method is called. Not typically invoked directly by application code.

Code Reference

Source Location

Repository: dolphinscheduler
File: dolphinscheduler-extract/dolphinscheduler-extract-base/src/main/java/org/apache/dolphinscheduler/extract/base/client/NettyRemotingClient.java (L115-191)
File: dolphinscheduler-extract/dolphinscheduler-extract-base/src/main/java/org/apache/dolphinscheduler/extract/base/protocal/Transporter.java (L34-48)
File: dolphinscheduler-extract/dolphinscheduler-extract-base/src/main/java/org/apache/dolphinscheduler/extract/base/client/SyncClientMethodInvoker.java (L34-38)

Signature

public class NettyRemotingClient implements AutoCloseable {
    public NettyRemotingClient(NettyClientConfig clientConfig);

    public IRpcResponse sendSync(SyncRequestDto syncRequestDto);

    private void doSendSync(Host host, Transporter transporter,
                            ResponseFuture responseFuture);

    public Channel getOrCreateChannel(Host host);
    private Channel createChannel(Host host);
    public void onChannelInactive(Host host);
    @Override public void close();
}

@Data
public class Transporter {
    private TransporterHeader header;
    private byte[] body;

    public static Transporter of(TransporterHeader header, byte[] body);
    public static Transporter of(TransporterHeader header, StandardRpcRequest request);
    public static Transporter of(TransporterHeader header, StandardRpcResponse response);
}

Import

import org.apache.dolphinscheduler.extract.base.client.NettyRemotingClient;
import org.apache.dolphinscheduler.extract.base.protocal.Transporter;

I/O Contract

Inputs

Name	Type	Required	Description
syncRequestDto	SyncRequestDto	Yes	Contains Transporter, target Host, and timeout
transporter	Transporter	Yes	Wire-format message with header and serialized body

Outputs

Name	Type	Description
IRpcResponse	Interface	Response containing serialized return value or exception
RemoteException	Exception	Thrown on connection failure
RemoteTimeoutException	Exception	Thrown when ResponseFuture times out

Usage Examples

Internal Sync Call Flow

// Inside SyncClientMethodInvoker.invoke():
SyncRequestDto syncRequestDto = SyncRequestDto.builder()
    .transporter(Transporter.of(header, standardRpcRequest))
    .serverHost(Host.of(hostAddress))
    .timeoutMills(rpcMethod.timeout())
    .build();

IRpcResponse response = nettyRemotingClient.sendSync(syncRequestDto);
// Deserialize response body to method return type
return JsonSerializer.deserialize(response.getBody(), returnType);

Related Pages

Implements Principle

Principle:Apache_Dolphinscheduler_Synchronous_RPC_Execution

Requires Environment

Uses Heuristic

Heuristic:Apache_Dolphinscheduler_Netty_Thread_Sizing

Page Connections

Double-click a node to navigate. Hold to expand connections.

Principle

Implementation

Heuristic

Environment