Question

I have a typical netty server setup just a bit confused on the “proper” way to implement or rather add an OrderedMemoryAwareThreadPoolExecutor to a pipelinefactory for specific types of requests. For most requests the typical NIO request/response is fine. However for a specific type of request I’d like to use traditional threaded I/O (ala OMATPE) because of the potential for it being a long running request. What I’m doing now is parsing the URI to get the specific type of request. Short requests will be processed normally and requests of type “/long/running/request” I continue to send upstream which passes through an OMATPE which is then passed to an appropriate handler. Is this the way to go? The pipeline looks something like the following:

 public ChannelPipeline getPipeline() {
     return Channels.pipeline(
             new HttpMessageEncoder(),
             new HttpMessageDecoder(),
             new shortLivedRequestHandler(),
             executionHandler,
             new longLivedRequestHandler());
 }

In the ‘shortLivedRequestHandler’ those URI’s matching a “short-lived” regex will be processed and then sent downstream. If those URI’s happend to match a “long-lived” regex then we pass upstream to the “longLivedRequestHandler” which will in theory process in a non-blocking I/O thread and send response downstream when done.

Answer 1

You can try not using OMATPE and manually configuring and using your own ThreadPool.

// Stored as a private field in your pipeline and passed into the constructor of your handler
Executor executor = Executors.newFixedThreadPool(16); 

// In your handler
public class MyRequestHandler extends SimpleChannelUpstreamHandler {
    private Executor _executor = null;

    public MyRequestHandler (Executor executor) {
        _executor = executor;
    }

    public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {
        if (requestThatUseThreadPool) {
            _executor.execute(new Runnable() {
                @Override
                public void run() {
                   // Do some work in another thread
                   HttpResponse res = new DefaultHttpResponse(HTTP_1_1, OK);
                   res.setContent(ChannelBuffers.copiedBuffer("hello".toString(), UTF_8_CHARSET));
                   ChannelFuture f = ctx.getChannel().write(res);
                }
            });
        } else {
            // Do some work in this thread
            HttpResponse res = new DefaultHttpResponse(HTTP_1_1, OK);
            res.setContent(ChannelBuffers.copiedBuffer("hello".toString(), UTF_8_CHARSET));
            ChannelFuture f = ctx.getChannel().write(res);
        }
    }
}

Hope this helps.