/**
* Copyright 2012 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 com.netflix.hystrix.examples.demo;
import java.math.BigDecimal;
import java.net.HttpCookie;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.SynchronousQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import com.netflix.config.ConfigurationManager;
import com.netflix.hystrix.HystrixCommandKey;
import com.netflix.hystrix.HystrixCommandMetrics;
import com.netflix.hystrix.HystrixCommandMetrics.HealthCounts;
import com.netflix.hystrix.HystrixRequestLog;
import com.netflix.hystrix.strategy.concurrency.HystrixRequestContext;
/**
* Executable client that demonstrates the lifecycle, metrics, request log and behavior of HystrixCommands.
*/
public class HystrixCommandDemo {
public static void main(String args[]) {
new HystrixCommandDemo().startDemo();
}
public HystrixCommandDemo() {
/*
* Instead of using injected properties we'll set them via Archaius
* so the rest of the code behaves as it would in a real system
* where it picks up properties externally provided.
*/
ConfigurationManager.getConfigInstance().setProperty("hystrix.threadpool.default.coreSize", 8);
ConfigurationManager.getConfigInstance().setProperty("hystrix.command.CreditCardCommand.execution.isolation.thread.timeoutInMilliseconds", 3000);
ConfigurationManager.getConfigInstance().setProperty("hystrix.command.GetUserAccountCommand.execution.isolation.thread.timeoutInMilliseconds", 50);
// set the rolling percentile more granular so we see data change every second rather than every 10 seconds as is the default
ConfigurationManager.getConfigInstance().setProperty("hystrix.command.default.metrics.rollingPercentile.numBuckets", 60);
}
/*
* Thread-pool to simulate HTTP requests.
*
* Use CallerRunsPolicy so we can just keep iterating and adding to it and it will block when full.
*/
private final ThreadPoolExecutor pool = new ThreadPoolExecutor(5, 5, 5, TimeUnit.DAYS, new SynchronousQueue<Runnable>(), new ThreadPoolExecutor.CallerRunsPolicy());
public void startDemo() {
startMetricsMonitor();
while (true) {
runSimulatedRequestOnThread();
}
}
public void runSimulatedRequestOnThread() {
pool.execute(new Runnable() {
@Override
public void run() {
HystrixRequestContext context = HystrixRequestContext.initializeContext();
try {
executeSimulatedUserRequestForOrderConfirmationAndCreditCardPayment();
System.out.println("Request => " + HystrixRequestLog.getCurrentRequest().getExecutedCommandsAsString());
} catch (Exception e) {
e.printStackTrace();
} finally {
context.shutdown();
}
}
});
}
public void executeSimulatedUserRequestForOrderConfirmationAndCreditCardPayment() throws InterruptedException, ExecutionException {
/* fetch user object with http cookies */
UserAccount user = new GetUserAccountCommand(new HttpCookie("mockKey", "mockValueFromHttpRequest")).execute();
/* fetch the payment information (asynchronously) for the user so the credit card payment can proceed */
Future<PaymentInformation> paymentInformation = new GetPaymentInformationCommand(user).queue();
/* fetch the order we're processing for the user */
int orderIdFromRequestArgument = 13579;
Order previouslySavedOrder = new GetOrderCommand(orderIdFromRequestArgument).execute();
CreditCardCommand credit = new CreditCardCommand(previouslySavedOrder, paymentInformation.get(), new BigDecimal(123.45));
credit.execute();
}
public void startMetricsMonitor() {
Thread t = new Thread(new Runnable() {
@Override
public void run() {
while (true) {
/**
* Since this is a simple example and we know the exact HystrixCommandKeys we are interested in
* we will retrieve the HystrixCommandMetrics objects directly.
*
* Typically you would instead retrieve metrics from where they are published which is by default
* done using Servo: https://github.com/Netflix/Hystrix/wiki/Metrics-and-Monitoring
*/
// wait 5 seconds on each loop
try {
Thread.sleep(5000);
} catch (Exception e) {
// ignore
}
// we are using default names so can use class.getSimpleName() to derive the keys
HystrixCommandMetrics creditCardMetrics = HystrixCommandMetrics.getInstance(HystrixCommandKey.Factory.asKey(CreditCardCommand.class.getSimpleName()));
HystrixCommandMetrics orderMetrics = HystrixCommandMetrics.getInstance(HystrixCommandKey.Factory.asKey(GetOrderCommand.class.getSimpleName()));
HystrixCommandMetrics userAccountMetrics = HystrixCommandMetrics.getInstance(HystrixCommandKey.Factory.asKey(GetUserAccountCommand.class.getSimpleName()));
HystrixCommandMetrics paymentInformationMetrics = HystrixCommandMetrics.getInstance(HystrixCommandKey.Factory.asKey(GetPaymentInformationCommand.class.getSimpleName()));
// print out metrics
StringBuilder out = new StringBuilder();
out.append("\n");
out.append("#####################################################################################").append("\n");
out.append("# CreditCardCommand: " + getStatsStringFromMetrics(creditCardMetrics)).append("\n");
out.append("# GetOrderCommand: " + getStatsStringFromMetrics(orderMetrics)).append("\n");
out.append("# GetUserAccountCommand: " + getStatsStringFromMetrics(userAccountMetrics)).append("\n");
out.append("# GetPaymentInformationCommand: " + getStatsStringFromMetrics(paymentInformationMetrics)).append("\n");
out.append("#####################################################################################").append("\n");
System.out.println(out.toString());
}
}
private String getStatsStringFromMetrics(HystrixCommandMetrics metrics) {
StringBuilder m = new StringBuilder();
if (metrics != null) {
HealthCounts health = metrics.getHealthCounts();
m.append("Requests: ").append(health.getTotalRequests()).append(" ");
m.append("Errors: ").append(health.getErrorCount()).append(" (").append(health.getErrorPercentage()).append("%) ");
m.append("Mean: ").append(metrics.getExecutionTimePercentile(50)).append(" ");
m.append("75th: ").append(metrics.getExecutionTimePercentile(75)).append(" ");
m.append("90th: ").append(metrics.getExecutionTimePercentile(90)).append(" ");
m.append("99th: ").append(metrics.getExecutionTimePercentile(99)).append(" ");
}
return m.toString();
}
});
t.setDaemon(true);
t.start();
}
}