/**
* 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.Random;
import java.util.concurrent.CountDownLatch;
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.HystrixContextRunnable;
import com.netflix.hystrix.strategy.concurrency.HystrixRequestContext;
import rx.Observable;
import rx.Subscriber;
import rx.functions.Action0;
import rx.functions.Action1;
import rx.functions.Func1;
import rx.functions.Func2;
import rx.plugins.RxJavaPlugins;
import rx.plugins.RxJavaSchedulersHook;
/**
* Executable client that demonstrates the lifecycle, metrics, request log and behavior of HystrixCommands.
*/
public class HystrixCommandAsyncDemo {
// public static void main(String args[]) {
// new HystrixCommandAsyncDemo().startDemo(true);
// }
static class ContextAwareRxSchedulersHook extends RxJavaSchedulersHook {
@Override
public Action0 onSchedule(final Action0 initialAction) {
final Runnable initialRunnable = new Runnable() {
@Override
public void run() {
initialAction.call();
}
};
final Runnable wrappedRunnable =
new HystrixContextRunnable(initialRunnable);
return new Action0() {
@Override
public void call() {
wrappedRunnable.run();
}
};
}
}
public HystrixCommandAsyncDemo() {
/*
* 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);
RxJavaPlugins.getInstance().registerSchedulersHook(new ContextAwareRxSchedulersHook());
}
public void startDemo(final boolean shouldLog) {
startMetricsMonitor(shouldLog);
while (true) {
final HystrixRequestContext context = HystrixRequestContext.initializeContext();
Observable<CreditCardAuthorizationResult> o = observeSimulatedUserRequestForOrderConfirmationAndCreditCardPayment();
final CountDownLatch latch = new CountDownLatch(1);
o.subscribe(new Subscriber<CreditCardAuthorizationResult>() {
@Override
public void onCompleted() {
latch.countDown();
context.shutdown();
}
@Override
public void onError(Throwable e) {
e.printStackTrace();
latch.countDown();
context.shutdown();
}
@Override
public void onNext(CreditCardAuthorizationResult creditCardAuthorizationResult) {
if (shouldLog) {
System.out.println("Request => " + HystrixRequestLog.getCurrentRequest().getExecutedCommandsAsString());
}
}
});
try {
latch.await(5000, TimeUnit.MILLISECONDS);
} catch (InterruptedException ex) {
System.out.println("INTERRUPTED!");
}
}
}
private final static Random r = new Random();
private class Pair<A, B> {
private final A a;
private final B b;
Pair(A a, B b) {
this.a = a;
this.b = b;
}
A a() {
return this.a;
}
B b() {
return this.b;
}
}
public Observable<CreditCardAuthorizationResult> observeSimulatedUserRequestForOrderConfirmationAndCreditCardPayment() {
/* fetch user object with http cookies */
try {
Observable<UserAccount> user = new GetUserAccountCommand(new HttpCookie("mockKey", "mockValueFromHttpRequest")).observe();
/* fetch the payment information (asynchronously) for the user so the credit card payment can proceed */
Observable<PaymentInformation> paymentInformation = user.flatMap(new Func1<UserAccount, Observable<PaymentInformation>>() {
@Override
public Observable<PaymentInformation> call(UserAccount userAccount) {
return new GetPaymentInformationCommand(userAccount).observe();
}
});
/* fetch the order we're processing for the user */
int orderIdFromRequestArgument = 13579;
final Observable<Order> previouslySavedOrder = new GetOrderCommand(orderIdFromRequestArgument).observe();
return Observable.zip(paymentInformation, previouslySavedOrder, new Func2<PaymentInformation, Order, Pair<PaymentInformation, Order>>() {
@Override
public Pair<PaymentInformation, Order> call(PaymentInformation paymentInformation, Order order) {
return new Pair<PaymentInformation, Order>(paymentInformation, order);
}
}).flatMap(new Func1<Pair<PaymentInformation, Order>, Observable<CreditCardAuthorizationResult>>() {
@Override
public Observable<CreditCardAuthorizationResult> call(Pair<PaymentInformation, Order> pair) {
return new CreditCardCommand(pair.b(), pair.a(), new BigDecimal(123.45)).observe();
}
});
} catch (IllegalArgumentException ex) {
return Observable.error(ex);
}
}
public void startMetricsMonitor(final boolean shouldLog) {
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()));
if (shouldLog) {
// 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();
}
}