/*
* Copyright 2013 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 feign.ribbon;
import com.google.common.base.Throwables;
import com.netflix.client.ClientException;
import com.netflix.client.ClientFactory;
import com.netflix.client.config.IClientConfig;
import com.netflix.loadbalancer.ILoadBalancer;
import java.io.IOException;
import java.net.URI;
import javax.inject.Inject;
import javax.inject.Named;
import javax.inject.Singleton;
import dagger.Provides;
import feign.Client;
import feign.Request;
import feign.Response;
/**
* Adding this module will override URL resolution of {@link feign.Client Feign's client},
* adding smart routing and resiliency capabilities provided by Ribbon.
* <br>
* When using this, ensure the {@link feign.Target#url()} is set to as {@code http://clientName}
* or {@code https://clientName}. {@link com.netflix.client.config.IClientConfig#getClientName() clientName}
* will lookup the real url and port of your service dynamically.
* <br>
* Ex.
* <pre>
* MyService api = Feign.create(MyService.class, "http://myAppProd", new RibbonModule());
* </pre>
* Where {@code myAppProd} is the ribbon client name and {@code myAppProd.ribbon.listOfServers} configuration
* is set.
*/
@dagger.Module(overrides = true, library = true, complete = false)
public class RibbonModule {
@Provides @Named("delegate") Client delegate(Client.Default delegate) {
return delegate;
}
@Provides @Singleton Client httpClient(RibbonClient ribbon) {
return ribbon;
}
@Singleton
static class RibbonClient implements Client {
private final Client delegate;
@Inject
public RibbonClient(@Named("delegate") Client delegate) {
this.delegate = delegate;
}
@Override public Response execute(Request request, Request.Options options) throws IOException {
try {
URI asUri = URI.create(request.url());
String clientName = asUri.getHost();
URI uriWithoutSchemeAndPort = URI.create(request.url().replace(asUri.getScheme() + "://" + asUri.getHost(), ""));
LBClient.RibbonRequest ribbonRequest = new LBClient.RibbonRequest(request, uriWithoutSchemeAndPort);
return lbClient(clientName).executeWithLoadBalancer(ribbonRequest).toResponse();
} catch (ClientException e) {
if (e.getCause() instanceof IOException) {
throw IOException.class.cast(e.getCause());
}
throw Throwables.propagate(e);
}
}
private LBClient lbClient(String clientName) {
IClientConfig config = ClientFactory.getNamedConfig(clientName);
ILoadBalancer lb = ClientFactory.getNamedLoadBalancer(clientName);
return new LBClient(delegate, lb, config);
}
}
}