hystrix-metrics-event-stream主要提供了一些servlet,可以让用户通过http请求获取metrics信息。
HystrixSampleSseServlet
继承了HttpServlet,不断从sampleStream中读取值并返回,直到sampleStream发送complete或出现异常。
private void handleRequest(HttpServletRequest request, final HttpServletResponse response) throws ServletException, IOException { ... sampleSubscription = sampleStream .observeOn(Schedulers.io()) .subscribe(new Subscriber<String>() { @Override public void onCompleted() { logger.error("HystrixSampleSseServlet: ({}) received unexpected OnCompleted from sample stream", getClass().getSimpleName()); moreDataWillBeSent.set(false); } @Override public void onError(Throwable e) { moreDataWillBeSent.set(false); } @Override public void onNext(String sampleDataAsString) { if (sampleDataAsString != null) { try { writer.print("data: " + sampleDataAsString + "\n\n"); // explicitly check for client disconnect - PrintWriter does not throw exceptions if (writer.checkError()) { moreDataWillBeSent.set(false); } writer.flush(); } catch (Exception ex) { moreDataWillBeSent.set(false); } } } }); while (moreDataWillBeSent.get() && !isDestroyed) { try { Thread.sleep(pausePollerThreadDelayInMs); //in case stream has not started emitting yet, catch any clients which connect/disconnect before emits start writer.print("ping: \n\n"); // explicitly check for client disconnect - PrintWriter does not throw exceptions if (writer.checkError()) { moreDataWillBeSent.set(false); } writer.flush(); } catch (Exception ex) { moreDataWillBeSent.set(false); } } } } finally { decrementCurrentConcurrentConnections(); if (sampleSubscription != null && !sampleSubscription.isUnsubscribed()) { sampleSubscription.unsubscribe(); } } }
HystrixConfigSseServlet
继承HystrixSampleSseServlet,读取HystrixConfigurationStream流数据。
public HystrixConfigSseServlet() { this(HystrixConfigurationStream.getInstance().observe(), DEFAULT_PAUSE_POLLER_THREAD_DELAY_IN_MS); } /* package-private */ HystrixConfigSseServlet(Observable<HystrixConfiguration> sampleStream, int pausePollerThreadDelayInMs) { super(sampleStream.map(new Func1<HystrixConfiguration, String>() { @Override public String call(HystrixConfiguration hystrixConfiguration) { return SerialHystrixConfiguration.toJsonString(hystrixConfiguration); } }), pausePollerThreadDelayInMs); }
HystrixMetricsStreamServlet
继承HystrixSampleSseServlet,读取HystrixDashboardStream流数据。
public HystrixMetricsStreamServlet() { this(HystrixDashboardStream.getInstance().observe(), DEFAULT_PAUSE_POLLER_THREAD_DELAY_IN_MS); } /* package-private */ HystrixMetricsStreamServlet(Observable<HystrixDashboardStream.DashboardData> sampleStream, int pausePollerThreadDelayInMs) { super(sampleStream.concatMap(new Func1<HystrixDashboardStream.DashboardData, Observable<String>>() { @Override public Observable<String> call(HystrixDashboardStream.DashboardData dashboardData) { return Observable.from(SerialHystrixDashboardData.toMultipleJsonStrings(dashboardData)); } }), pausePollerThreadDelayInMs); }
HystrixRequestEventsSseServlet
继承HystrixSampleSseServlet,读取HystrixRequestEventsStream流数据。
public HystrixRequestEventsSseServlet() { this(HystrixRequestEventsStream.getInstance().observe(), DEFAULT_PAUSE_POLLER_THREAD_DELAY_IN_MS); } /* package-private */ HystrixRequestEventsSseServlet(Observable<HystrixRequestEvents> sampleStream, int pausePollerThreadDelayInMs) { super(sampleStream.map(new Func1<HystrixRequestEvents, String>() { @Override public String call(HystrixRequestEvents requestEvents) { return SerialHystrixRequestEvents.toJsonString(requestEvents); } }), pausePollerThreadDelayInMs); }
HystrixUtilizationSseServlet
继承HystrixSampleSseServlet,读取HystrixUtilizationStream流数据。
public HystrixUtilizationSseServlet() { this(HystrixUtilizationStream.getInstance().observe(), DEFAULT_PAUSE_POLLER_THREAD_DELAY_IN_MS); } /* package-private */ HystrixUtilizationSseServlet(Observable<HystrixUtilization> sampleStream, int pausePollerThreadDelayInMs) { super(sampleStream.map(new Func1<HystrixUtilization, String>() { @Override public String call(HystrixUtilization hystrixUtilization) { return SerialHystrixUtilization.toJsonString(hystrixUtilization); } }), pausePollerThreadDelayInMs); }
使用hystrix-metrics-event-stream
- 引入hystrix-metrics-event-stream-*.jar包
- 添加web.xml配置
<servlet> <description></description> <display-name>HystrixUtilizationSseServlet</display-name> <servlet-name>HystrixUtilizationSseServlet</servlet-name> <servlet-class>com.netflix.hystrix.contrib.sample.stream.HystrixUtilizationSseServlet</servlet-class> </servlet>
<servlet-mapping> <servlet-name>HystrixUtilizationSseServlet</servlet-name> <url-pattern>/hystrix/utilization.stream</url-pattern> </servlet-mapping>