Add metrics logging to demo

hystrix-examples/src/main/java/com/netflix/hystrix/examples/demo/HystrixCommandDemo.java

@@ -1,12 +1,12 @@
 /**
  * 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
- *
+ * 
+ * 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.
@@ -23,6 +23,9 @@
 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;
 
@@ -40,9 +43,10 @@ public static void main(String args[]) {
         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);
 
-        new HystrixCommandDemo().run();
-
+        new HystrixCommandDemo().startDemo();
     }
 
     /*
@@ -52,7 +56,8 @@ public static void main(String args[]) {
      */
     private final ThreadPoolExecutor pool = new ThreadPoolExecutor(5, 5, 5, TimeUnit.DAYS, new SynchronousQueue<Runnable>(), new ThreadPoolExecutor.CallerRunsPolicy());
 
-    public void run() {
+    public void startDemo() {
+        startMetricsMonitor();
         while (true) {
             executeSimulatedUserRequestForOrderConfirmationAndCreditCardPayment();
         }
@@ -85,8 +90,65 @@ public void run() {
                     context.shutdown();
                 }
             }
-
         });
+    }
+
+    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();
     }
 }