io.fabric8.kubeflix.examples.helloribbon.HelloRibbonServlet.java Source code

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Here is the source code for io.fabric8.kubeflix.examples.helloribbon.HelloRibbonServlet.java

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/*
 * Copyright (C) 2015 Red Hat, 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.fabric8.kubeflix.examples.helloribbon;

import com.netflix.hystrix.HystrixCommandGroupKey;
import com.netflix.hystrix.HystrixCommandKey;
import com.netflix.hystrix.HystrixCommandProperties;
import com.netflix.hystrix.HystrixInvokableInfo;
import com.netflix.hystrix.HystrixObservableCommand;
import com.netflix.ribbon.ClientOptions;
import com.netflix.ribbon.Ribbon;
import com.netflix.ribbon.http.HttpRequestTemplate;
import com.netflix.ribbon.http.HttpResourceGroup;
import com.netflix.ribbon.hystrix.FallbackHandler;
import io.fabric8.kubeflix.ribbon.KubernetesClientConfig;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import rx.Observable;
import rx.functions.Action1;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Map;

public class HelloRibbonServlet extends HttpServlet {

    private HttpResourceGroup group = Ribbon.createHttpResourceGroupBuilder("hello-hystrix")
            .withClientOptions(ClientOptions.from(new KubernetesClientConfig())).build();

    private HttpRequestTemplate<ByteBuf> template = group.newTemplateBuilder("HelloRibbon").withMethod("GET")
            .withUriTemplate("/hello")
            .withHystrixProperties(HystrixObservableCommand.Setter
                    .withGroupKey(HystrixCommandGroupKey.Factory.asKey("HelloRibbonGroup"))
                    .andCommandKey(HystrixCommandKey.Factory.asKey("HelloRibbon")).andCommandPropertiesDefaults(
                            HystrixCommandProperties.Setter().withExecutionTimeoutInMilliseconds(5000)))
            .withFallbackProvider(new HelloFallbackProvider()).build();

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        resp.setContentType("text/html");
        final PrintWriter out = resp.getWriter();
        template.requestBuilder().build().toObservable().toBlocking().forEach(new Action1<ByteBuf>() {
            @Override
            public void call(ByteBuf buffer) {
                byte[] bytes = new byte[buffer.readableBytes()];
                buffer.readBytes(bytes);
                String next = new String(bytes);
                out.println("<h1>" + next + "</h1>");
            }
        });
    }

    private class HelloFallbackProvider implements FallbackHandler<ByteBuf> {
        private static final String FALLBACK_MESSAGE = "Fallback Hello from HelloRibbonServlet";

        @Override
        public Observable<ByteBuf> getFallback(HystrixInvokableInfo<?> hystrixInfo,
                Map<String, Object> requestProperties) {

            return Observable.just(Unpooled.copiedBuffer(FALLBACK_MESSAGE.getBytes()));
        }
    }
}