alibaba/canal · error · IllegalArgumentException

at least 1 node required.

Error message

at least 1 node required.

What it means

Error "at least 1 node required." thrown in alibaba/canal.

Source

Thrown at client/src/main/java/com/alibaba/otter/canal/client/impl/SimpleNodeAccessStrategy.java:22

import java.util.ArrayList;
import java.util.List;

import com.alibaba.otter.canal.client.CanalNodeAccessStrategy;

/**
 * 简单版本的node访问实现
 * 
 * @author jianghang 2012-10-29 下午08:00:23
 * @version 1.0.0
 */
public class SimpleNodeAccessStrategy implements CanalNodeAccessStrategy {

    private List<SocketAddress> nodes = new ArrayList<>();
    private int                 index = 0;

    public SimpleNodeAccessStrategy(List<? extends SocketAddress> nodes){
        if (nodes == null || nodes.size() < 1) {
            throw new IllegalArgumentException("at least 1 node required.");
        }
        this.nodes.addAll(nodes);
    }

    @Override
    public SocketAddress nextNode() {
        try {
            return nodes.get(index);
        } finally {
            index = (index + 1) % nodes.size();
        }
    }

    @Override
    public SocketAddress currentNode() {
        return nodes.get(index);
    }

View on GitHub (pinned to 87be50e876)

Solutions

1. Provide at least one SocketAddress node when constructing SimpleNodeAccessStrategy.
2. Check that the configured canal server address list (canal.server / zk path resolution) is not empty.

When it happens

Trigger: Thrown at client/src/main/java/com/alibaba/otter/canal/client/impl/SimpleNodeAccessStrategy.java:22 when the library encounters an invalid state.

Common situations: Empty node list. Validate configuration at construction time so a zero-node strategy can never be built; reject blank addresses individually.

AI-assisted analysis of alibaba/canal@87be50e876 (2026-08-14). Data as JSON: /api/errors/25501b52abe90806. Report an issue: GitHub.