Bootstrap a EmbeddedChannel failed

I found EmbeddedChannel will registered itself in its constructor at EmbeddedChannel.java#L178. And Bootstrap connect will try register channel after create it and found it had been registered and throw exception AbstractBootstrap.java#L332.

Because it was just for some test purpose, so it’s not a big deal. But it would be better if we can bootstrap a EmbeddedChannel! Some of my idea: maybe we can ignore register if registered at EmbeddedEventLoop.java#L130, because EmbeddedChannel never blocked.

Expected behavior

Following code should pass.

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.embedded.EmbeddedChannel;
import org.junit.Test;

import static org.junit.Assert.assertTrue;

public class BootstrapEmbeddedChannel {
    @Test
    public void shouldGetEmbeddedChanenl() {
        EmbeddedChannel firstCh = new EmbeddedChannel();

        ChannelFuture secondChFuture = new Bootstrap()
                .group(firstCh.eventLoop())
                .channel(firstCh.getClass())
                .handler(new ChannelInitializer<Channel>() {
                    @Override
                    protected void initChannel(Channel ch) throws Exception {

                    }
                }).connect("localhost", 9999);

        assertTrue(secondChFuture.isSuccess());
    }
}

Actual behavior

java.lang.IllegalStateException: registered to an event loop already
	at io.netty.channel.AbstractChannel$AbstractUnsafe.register(AbstractChannel.java:460)
	at io.netty.channel.embedded.EmbeddedEventLoop.register(EmbeddedEventLoop.java:130)
	at io.netty.channel.embedded.EmbeddedEventLoop.register(EmbeddedEventLoop.java:124)
	at io.netty.bootstrap.AbstractBootstrap.initAndRegister(AbstractBootstrap.java:332)
	at io.netty.bootstrap.Bootstrap.doResolveAndConnect(Bootstrap.java:163)
	at io.netty.bootstrap.Bootstrap.connect(Bootstrap.java:145)
	at io.netty.bootstrap.Bootstrap.connect(Bootstrap.java:126)

Steps to reproduce

Minimal yet complete reproducer code (or URL to code)

Same above.

Netty version

4.1.9.Final

JVM version (e.g. java -version)

1.8.0_65

OS version (e.g. uname -a)

Darwin Kernel Version 16.4.0: Thu Dec 22 22:53:21 PST 2016; root:xnu-3789.41.3~3/RELEASE_X86_64 x86_64

[asarkar]

@chhsiao90 Hmm. I couldn’t get bootstrap working in unit test so I took it out using a factory class. It’s cleaner design, but still bothering me. Netty has good examples, but sadly no accompanying unit testing samples.

Here my learning project: https://github.com/asarkar/kotlin/tree/master/netty-learning/proxy

[chhsiao90]

@asarkar - agreed! that’s what I’m doing too, create a channel factory instead of using bootstrap directly. And writing unit test is always hard…