io.reactivex.netty.examples.http.loadbalancing.HttpLoadBalancer Maven / Gradle / Ivy
/*
* Copyright 2016 Netflix, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package io.reactivex.netty.examples.http.loadbalancing;
import io.netty.handler.codec.http.HttpResponseStatus;
import io.reactivex.netty.client.events.ClientEventListener;
import io.reactivex.netty.examples.tcp.loadbalancing.AbstractLoadBalancer;
import io.reactivex.netty.protocol.http.client.events.HttpClientEventsListener;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.concurrent.TimeUnit;
/**
* This is an implementation of {@link AbstractLoadBalancer} for HTTP clients.
*
* This load balancer uses a naive failure detector that removes the host on the first 503 HTTP response. The
* intention here is just to demonstrate how to write complex load balancing logic using lower level constructs in the
* client.
*
* @param Type of Objects written on the connections created by this load balancer.
* @param Type of Objects read from the connections created by this load balancer.
*
* @see AbstractLoadBalancer
* @see HttpLoadBalancingClient
*/
public class HttpLoadBalancer extends AbstractLoadBalancer {
private static final Logger logger = LoggerFactory.getLogger(HttpLoadBalancer.class);
public HttpLoadBalancer() {
super();
}
@Override
protected ClientEventListener newListener() {
return new ClientEventListenerImpl();
}
@Override
protected long getWeight(ClientEventListener eventListener) {
return ((ClientEventListenerImpl)eventListener).weight;
}
private static class ClientEventListenerImpl extends HttpClientEventsListener {
private volatile long weight = Long.MAX_VALUE;
@Override
public void onConnectFailed(long duration, TimeUnit timeUnit, Throwable throwable) {
weight = Long.MIN_VALUE;
}
@Override
public void onByteRead(long bytesRead) {
super.onByteRead(bytesRead);
}
@Override
public void onResponseHeadersReceived(int responseCode, long duration, TimeUnit timeUnit) {
logger.error("Response code: " + responseCode);
if (HttpResponseStatus.SERVICE_UNAVAILABLE.code() == responseCode) {
weight = Long.MIN_VALUE;
}
}
}
}