配置

    <properties>
        <!-- 依賴版本 -->
        <hystrix.version>1.3.16</hystrix.version>
        <hystrix-metrics-event-stream.version>1.1.2</hystrix-metrics-event-stream.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>com.netflix.hystrix</groupId>
            <artifactId>hystrix-core</artifactId>
            <version>${hystrix.version}</version>
        </dependency>
        <dependency>
            <groupId>com.netflix.hystrix</groupId>
            <artifactId>hystrix-metrics-event-stream</artifactId>
            <version>${hystrix-metrics-event-stream.version}</version>
        </dependency>
    </dependencies>

使用

超時(shí)降級(jí)

package com.fulton_shaw;

import com.fulton_shaw.common.util.concurrent.ThreadUtils;
import com.netflix.hystrix.HystrixCommand;
import com.netflix.hystrix.HystrixCommandGroupKey;
import com.netflix.hystrix.HystrixCommandProperties;

/**
 * @author xiaohuadong
 * @date 2018/11/06
 */
public class FallbackCommand extends HystrixCommand<String> {
    public FallbackCommand(String name){
        super(Setter.withGroupKey(HystrixCommandGroupKey.Factory.asKey(name))
        .andCommandPropertiesDefaults(HystrixCommandProperties.Setter().withExecutionIsolationThreadTimeoutInMilliseconds(500)));

    }

    @Override
    protected String getFallback() {
        return "FALLBACK";
    }

    protected String run() throws Exception {
        ThreadUtils.sleepRandom(300,700);
        return "SUCCEED RUN";
    }
}

package com.fulton_shaw;

import com.fulton_shaw.common.util.concurrent.ExpectUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.concurrent.Callable;

/**
 * @author xiaohuadong
 * @date 2018/11/06
 */
public class FallbackMain {
    private static final Logger LOG = LoggerFactory.getLogger(FallbackMain.class);
    public static void main(String[] args) {
        ExpectUtils.untilTrueCount(20, new Callable<Boolean>() {
            public Boolean call() throws Exception {
                FallbackCommand command = new FallbackCommand("will-you-fallback");

                String result = command.execute();
                LOG.info("{}", result);
                return "FALLBACK".equals(result);
            }
        });

        LOG.info("end");

        System.exit(0);

    }
}

基本設(shè)計(jì)

接口+Factory+intern構(gòu)成一個(gè)Hystrix的全局注冊(cè)中心
同時(shí)，將UnitTest放到類的后面，以便發(fā)布時(shí)，將測(cè)試包含在內(nèi)。

很大量是依賴RxJava庫(kù)，其中，Observable，Operator非常經(jīng)典。
HystrixCommand運(yùn)行時(shí)，是處于線程池中的。

服務(wù)場(chǎng)景

1.單個(gè)服務(wù)熔斷：一個(gè)服務(wù)正常能夠接受2個(gè)并發(fā)訪問(wèn)，測(cè)試4個(gè)并發(fā)訪問(wèn)，帶有超時(shí)的場(chǎng)景

2.服務(wù)之間存在依賴的熔斷：服務(wù)A正常接受5個(gè)并發(fā)訪問(wèn)，服務(wù)B接受3個(gè)并發(fā)訪問(wèn)，服務(wù)C接受2個(gè)并發(fā)訪問(wèn)，服務(wù)A依賴B，B依賴C。

單服務(wù)模式下Hystrix的使用測(cè)試

構(gòu)造ThroughputService代表一般的服務(wù)，該服務(wù)能夠在一定時(shí)間內(nèi)返回，同時(shí)，有一個(gè)支持的最大并發(fā)量上限

package com.fulton_shaw.common.lang.testing;


import com.fulton_shaw.common.lang.FixedValueGetter;
import com.fulton_shaw.common.lang.ValueGetter;
import com.fulton_shaw.common.util.concurrent.ThreadUtils;
import com.google.common.base.Function;
import com.google.common.base.Preconditions;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.annotation.Nullable;
import javax.annotation.concurrent.ThreadSafe;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * @author xiaohuadong
 * @date 2018/11/08
 */
@ThreadSafe
public class ThroughPutService implements Service {
    private static final Logger LOG = LoggerFactory.getLogger(ThroughPutService.class);


    /* 服務(wù)時(shí)間 ， 單位:ms  小于等于0時(shí)，無(wú)需等待 */
    private ValueGetter<Long> serviceTimeStrategy;

    /* 最大并發(fā)數(shù) , 小于等于0時(shí)，無(wú)限制*/
    private final int maxConcurrent;

    /* 服務(wù)調(diào)用 */
    private Runnable beforeService;
    private Runnable afterService;


    /* 服務(wù)拒絕時(shí)調(diào)用 */
    private Runnable onDeny;


    /* 服務(wù)異常時(shí)調(diào)用 */
    private Function<Exception,Void> onException;

    private AtomicInteger currentConcurrent;


  /**
     * 調(diào)用服務(wù)
     *
     * @return 服務(wù)是否成功
     */
    public boolean tryService() {
        boolean canService = false;
        LOG.debug("{} --> beginning tryService,current concurrent = {}",ThreadUtils.getCurrentThreadName(),currentConcurrent.get());
        if (maxConcurrent <= 0) {
            currentConcurrent.incrementAndGet();
            canService = true;
        } else {
            // CAS
            while (true) {
                int old = currentConcurrent.get();
                if(old >= maxConcurrent){
                    break;
                }else if(currentConcurrent.compareAndSet(old, old + 1)){
                    canService = true;
                    break;
                }
            }
        }


        try {
            if (canService) {
                LOG.debug("{} --> gain tryService,current concurrent = {}",ThreadUtils.getCurrentThreadName(),currentConcurrent.get());
                beforeService.run();
                Long sleep = serviceTimeStrategy.get();
                LOG.debug("{} --> will sleep {} ms",ThreadUtils.getCurrentThreadName(),sleep);
                ThreadUtils.sleep(sleep);
                currentConcurrent.decrementAndGet();
                afterService.run();
            } else {
                onDeny.run();
            }
        }catch (Exception e){
            try {
                onException.apply(e);
            }catch (Exception ae){
                LOG.error("error happened while handing {}",e.toString(),ae);
            }
        }


        LOG.debug("{} --> end tryService,current concurrent = {}",ThreadUtils.getCurrentThreadName(),currentConcurrent.get());

        return canService;
    }

}

ThroughPutService類的tryService方法嘗試調(diào)用一個(gè)服務(wù)，如果當(dāng)前并發(fā)量尚未達(dá)到上限，則服務(wù)，否則，調(diào)用onDeny。若有錯(cuò)誤發(fā)生，則調(diào)用onException。
下面是對(duì)該Service的一個(gè)測(cè)試

public class ThroughPutServiceMain {
    public static void main(String[] args) {
        final ThroughPutService service = ThroughPutService.makeService(new RandomLongGetter(300, 500), 2);
        ThreadUtils.startThreadForTimesAndWait(5, new ProcessMethod<Integer>() {
            @Nullable
            @Override
            public void apply(@Nullable Integer input) {
                service.tryService();
            }
        });
    }

}

serivce的服務(wù)時(shí)間在300~500毫秒之間，隨機(jī)返回。最大允許的并發(fā)量是2。測(cè)試程序開(kāi)啟了5個(gè)線程來(lái)消費(fèi)這個(gè)服務(wù)，下面的結(jié)果顯示，只有其中兩個(gè)線程得到服務(wù)，其他均被拒絕。
得到服務(wù)的是Thread-2和Thread-3, gain tryService.
輸出結(jié)果：

15:39:46.789 [Thread-2] DEBUG com.fulton_shaw.common.lang.testing.ThroughPutService - Thread-2 --> beginning tryService,current concurrent = 0
15:39:46.789 [Thread-4] DEBUG com.fulton_shaw.common.lang.testing.ThroughPutService - Thread-4 --> beginning tryService,current concurrent = 0
15:39:46.789 [Thread-3] DEBUG com.fulton_shaw.common.lang.testing.ThroughPutService - Thread-3 --> beginning tryService,current concurrent = 0
15:39:46.789 [Thread-5] DEBUG com.fulton_shaw.common.lang.testing.ThroughPutService - Thread-5 --> beginning tryService,current concurrent = 0
15:39:46.789 [Thread-1] DEBUG com.fulton_shaw.common.lang.testing.ThroughPutService - Thread-1 --> beginning tryService,current concurrent = 0
15:39:46.791 [Thread-5] DEBUG com.fulton_shaw.common.lang.testing.ThroughPutService - Thread-5 --> end tryService,current concurrent = 2
15:39:46.791 [Thread-3] DEBUG com.fulton_shaw.common.lang.testing.ThroughPutService - Thread-3 --> gain tryService,current concurrent = 2
15:39:46.791 [Thread-2] DEBUG com.fulton_shaw.common.lang.testing.ThroughPutService - Thread-2 --> gain tryService,current concurrent = 2
15:39:46.791 [Thread-1] DEBUG com.fulton_shaw.common.lang.testing.ThroughPutService - Thread-1 --> end tryService,current concurrent = 2
15:39:46.791 [Thread-4] DEBUG com.fulton_shaw.common.lang.testing.ThroughPutService - Thread-4 --> end tryService,current concurrent = 2
15:39:46.791 [Thread-2] DEBUG com.fulton_shaw.common.lang.testing.ThroughPutService - Thread-2 --> will sleep 415 ms
15:39:46.791 [Thread-3] DEBUG com.fulton_shaw.common.lang.testing.ThroughPutService - Thread-3 --> will sleep 461 ms
15:39:47.206 [Thread-2] DEBUG com.fulton_shaw.common.lang.testing.ThroughPutService - Thread-2 --> end tryService,current concurrent = 1
15:39:47.252 [Thread-3] DEBUG com.fulton_shaw.common.lang.testing.ThroughPutService - Thread-3 --> end tryService,current concurrent = 0

ThroughPutService不能服務(wù)的情況有一種：就是最大并發(fā)量。
但是對(duì)于客戶端而言，ThroughPutService不能服務(wù)還包括一種情況：ThroughPutService本身的服務(wù)質(zhì)量--響應(yīng)時(shí)間超時(shí)。

HystrixCommand封裝ThroughPutService

我們首先識(shí)別出ThroughPutService服務(wù)不可用的情況，就是：1.超過(guò)服務(wù)的最大并發(fā)量 2.服務(wù)本身超時(shí)
在下面的Command的封裝中，run會(huì)調(diào)用service，但是service可能返回false，因此，在返回false的情況下，我們應(yīng)當(dāng)拋出異常，表明服務(wù)不可用，迫使Hystrix轉(zhuǎn)向getFallback()調(diào)用。
此外，即使service正?？捎?，但是服務(wù)時(shí)間超時(shí)，Hystrix本身會(huì)對(duì)run進(jìn)行超時(shí)判斷，因此，它也會(huì)轉(zhuǎn)向getFallback()

package com.fulton_shaw.third_party_demo.hystrix;

public class SingleServiceCommand extends HystrixCommand<Void> {
    private static final Logger LOG = LoggerFactory.getLogger(SingleServiceCommand.class);
    private ThroughPutService service;


    protected SingleServiceCommand(ThroughPutService service,long time) {
        super(HystrixCommand.Setter.
                withGroupKey(HystrixCommandGroupKey.Factory.asKey(SingleServiceCommand.class.getSimpleName()))
                .andCommandPropertiesDefaults(HystrixCommandProperties.Setter().withExecutionTimeoutEnabled(true).withExecutionTimeoutInMilliseconds((int)time))
        );
        this.service = service;
    }

    @Override
    protected Void run() throws Exception {
        boolean succeed = service.tryService();
        LOG.info("{} --> tryService succeed? {} ",ThreadUtils.getCurrentThreadName(),succeed);
        if(!succeed){
            throw  new RuntimeException(String.format("%s --> try service rejected", ThreadUtils.getCurrentThreadName()));
        }
        return null;
    }

    @Override
    protected Void getFallback() {
        LOG.info("{} --> getting Fallback",Thread.currentThread().getName());
        return null;
    }
}

測(cè)試封裝的HystrixCommand

package com.fulton_shaw.third_party_demo.hystrix;

public class SingleServiceDemo {
    private static final Logger LOG = LoggerFactory.getLogger(SingleServiceDemo.class);

    public static void main(String[] args) {

        final ThroughPutService service = ThroughPutService.makeService(new RandomLongGetter(1000, 3000), 2);


        final AtomicInteger denied = new AtomicInteger(0);
        service.setOnDeny(new Runnable() {
            @Override
            public void run() {
                denied.incrementAndGet();
            }
        });

        int timeout = 2000;
        int commandCount = 4;
        final SingleServiceCommand[] commands = new SingleServiceCommand[commandCount];
        for (int i = 0; i < commandCount; i++) {
            commands[i] = new SingleServiceCommand(service,timeout);
        }

        ThreadUtils.startThreadForTimesAndWait(4, new ProcessMethod<Integer>() {
            @Nullable
            @Override
            public void apply(@Nullable Integer i) {
                commands[i].execute();
            }
        });

        LOG.info("concurrent denied = {}", denied.get());
    }
}

在上面的程序中，我們新建了一個(gè)服務(wù)，隨機(jī)返回時(shí)間是1000-3000ms之間，我們將服務(wù)的超時(shí)時(shí)間設(shè)置為2000ms，然后使用denied變量記錄服務(wù)被拒絕的數(shù)量。然后，我們新建了4個(gè)對(duì)該服務(wù)的調(diào)用實(shí)例，由Hystrix管理。
從下面的輸出結(jié)果中，我們可以看出4和3獲得服務(wù)執(zhí)行，其中4超時(shí)，3沒(méi)有超時(shí)，1和2均被拒絕服務(wù)。
由于1,2被拒絕服務(wù)，因此他們拋出異常之后，Hystrix轉(zhuǎn)向了Fallback，我們可以看到的時(shí)，拋出異常之后，getFallback仍然處于同一線程之中。
但是4轉(zhuǎn)向Fallback之后，卻是由HystrixTimer-1來(lái)調(diào)用的，而原來(lái)的線程仍然繼續(xù)運(yùn)行，我們可以看到4最后也輸出了 end tryService.
輸出結(jié)果：

16:22:04.243 [hystrix-SingleServiceCommand-4] DEBUG com.fulton_shaw.common.lang.testing.ThroughPutService - hystrix-SingleServiceCommand-4 --> beginning tryService,current concurrent = 0
16:22:04.244 [hystrix-SingleServiceCommand-4] DEBUG com.fulton_shaw.common.lang.testing.ThroughPutService - hystrix-SingleServiceCommand-4 --> gain tryService,current concurrent = 1
16:22:04.243 [hystrix-SingleServiceCommand-3] DEBUG com.fulton_shaw.common.lang.testing.ThroughPutService - hystrix-SingleServiceCommand-3 --> beginning tryService,current concurrent = 0
16:22:04.244 [hystrix-SingleServiceCommand-4] DEBUG com.fulton_shaw.common.lang.testing.ThroughPutService - hystrix-SingleServiceCommand-4 --> will sleep 2665 ms
16:22:04.244 [hystrix-SingleServiceCommand-3] DEBUG com.fulton_shaw.common.lang.testing.ThroughPutService - hystrix-SingleServiceCommand-3 --> gain tryService,current concurrent = 2
16:22:04.244 [hystrix-SingleServiceCommand-3] DEBUG com.fulton_shaw.common.lang.testing.ThroughPutService - hystrix-SingleServiceCommand-3 --> will sleep 1284 ms
16:22:04.244 [hystrix-SingleServiceCommand-1] DEBUG com.fulton_shaw.common.lang.testing.ThroughPutService - hystrix-SingleServiceCommand-1 --> beginning tryService,current concurrent = 2
16:22:04.244 [hystrix-SingleServiceCommand-1] DEBUG com.fulton_shaw.common.lang.testing.ThroughPutService - hystrix-SingleServiceCommand-1 --> end tryService,current concurrent = 2
16:22:04.244 [hystrix-SingleServiceCommand-1] INFO  com.fulton_shaw.third_party_demo.hystrix.SingleServiceCommand - hystrix-SingleServiceCommand-1 --> tryService succeed? false
16:22:04.244 [hystrix-SingleServiceCommand-2] DEBUG com.fulton_shaw.common.lang.testing.ThroughPutService - hystrix-SingleServiceCommand-2 --> beginning tryService,current concurrent = 2
16:22:04.244 [hystrix-SingleServiceCommand-2] DEBUG com.fulton_shaw.common.lang.testing.ThroughPutService - hystrix-SingleServiceCommand-2 --> end tryService,current concurrent = 2
16:22:04.244 [hystrix-SingleServiceCommand-2] INFO  com.fulton_shaw.third_party_demo.hystrix.SingleServiceCommand - hystrix-SingleServiceCommand-2 --> tryService succeed? false
16:22:04.245 [hystrix-SingleServiceCommand-1] DEBUG com.netflix.hystrix.AbstractCommand - Error executing HystrixCommand.run(). Proceeding to fallback logic ...
java.lang.RuntimeException: hystrix-SingleServiceCommand-1 --> try service rejected
at com.fulton_shaw.third_party_demo.hystrix.SingleServiceCommand.run(SingleServiceCommand.java:34) ~[classes/:?]
...
16:22:04.245 [hystrix-SingleServiceCommand-2] DEBUG com.netflix.hystrix.AbstractCommand - Error executing HystrixCommand.run(). Proceeding to fallback logic ...
java.lang.RuntimeException: hystrix-SingleServiceCommand-2 --> try service rejected
at com.fulton_shaw.third_party_demo.hystrix.SingleServiceCommand.run(SingleServiceCommand.java:34) ~[classes/:?]
...
16:22:04.254 [hystrix-SingleServiceCommand-2] INFO  com.fulton_shaw.third_party_demo.hystrix.SingleServiceCommand - hystrix-SingleServiceCommand-2 --> getting Fallback
16:22:04.257 [hystrix-SingleServiceCommand-1] INFO  com.fulton_shaw.third_party_demo.hystrix.SingleServiceCommand - hystrix-SingleServiceCommand-1 --> getting Fallback
16:22:05.528 [hystrix-SingleServiceCommand-3] DEBUG com.fulton_shaw.common.lang.testing.ThroughPutService - hystrix-SingleServiceCommand-3 --> end tryService,current concurrent = 1
16:22:05.528 [hystrix-SingleServiceCommand-3] INFO  com.fulton_shaw.third_party_demo.hystrix.SingleServiceCommand - hystrix-SingleServiceCommand-3 --> tryService succeed? true
16:22:06.231 [hystrix-SingleServiceCommand-4] DEBUG com.fulton_shaw.common.lang.testing.ThroughPutService - hystrix-SingleServiceCommand-4 --> end tryService,current concurrent = 0
16:22:06.231 [hystrix-SingleServiceCommand-4] INFO  com.fulton_shaw.third_party_demo.hystrix.SingleServiceCommand - hystrix-SingleServiceCommand-4 --> tryService succeed? true
16:22:06.232 [HystrixTimer-1] INFO  com.fulton_shaw.third_party_demo.hystrix.SingleServiceCommand - HystrixTimer-1 --> getting Fallback
16:22:06.233 [main] INFO  com.fulton_shaw.third_party_demo.hystrix.SingleServiceDemo - concurrent denied = 2

多服務(wù)和服務(wù)存在依賴的場(chǎng)景測(cè)試

2.服務(wù)之間存在依賴的熔斷：服務(wù)A正常接受5個(gè)并發(fā)訪問(wèn)，服務(wù)B接受3個(gè)并發(fā)訪問(wèn)，服務(wù)C接受2個(gè)并發(fā)訪問(wèn)，服務(wù)A依賴B，B依賴C。
只需要將服務(wù)

參考

http://www.itdecent.cn/p/fc19f6ed6d0d

http://www.itdecent.cn/p/05f3e75b3739

Hystrix中的設(shè)計(jì)哲學(xué)

Hystrix使用總結(jié)

execute方法會(huì)開(kāi)啟新的線程執(zhí)行，當(dāng)前線程阻塞等待那個(gè)線程。
所謂信號(hào)量隔離，是指當(dāng)服務(wù)并發(fā)量大于信號(hào)量設(shè)定的值時(shí)，自動(dòng)降級(jí)
熔斷是指降級(jí)的終極情況，

假設(shè)線路內(nèi)的容量（請(qǐng)求QPS）達(dá)到一定閾值（通過(guò) HystrixCommandProperties.circuitBreakerRequestVolumeThreshold() 配置）
同時(shí)，假設(shè)線路內(nèi)的錯(cuò)誤率達(dá)到一定閾值（通過(guò) HystrixCommandProperties.circuitBreakerErrorThresholdPercentage() 配置）
熔斷器將從『閉路』轉(zhuǎn)換成『開(kāi)路』
若此時(shí)是『開(kāi)路』狀態(tài)，熔斷器將短路后續(xù)所有經(jīng)過(guò)該熔斷器的請(qǐng)求，這些請(qǐng)求直接走『失敗回退邏輯』
經(jīng)過(guò)一定時(shí)間（即『休眠窗口』，通過(guò) HystrixCommandProperties.circuitBreakerSleepWindowInMilliseconds() 配置），后續(xù)第一個(gè)請(qǐng)求將會(huì)被允許通過(guò)熔斷器（此時(shí)熔斷器處于『半開(kāi)』狀態(tài)），若該請(qǐng)求失敗，熔斷器將又進(jìn)入『開(kāi)路』狀態(tài)，且在休眠窗口內(nèi)保持此狀態(tài)；若該請(qǐng)求成功，熔斷器將進(jìn)入『閉路』狀態(tài)，回到邏輯1循環(huán)往復(fù)。

其他特性

緩存
組合請(qǐng)求
Dashboard監(jiān)控

色偷偷精品伊人,欧洲久久精品,欧美综合婷婷骚逼,国产AV主播,国产最新探花在线,九色在线视频一区,伊人大交九欧美,1769亚洲,黄色成人av

Hystrix

Hystrix

配置

使用

超時(shí)降級(jí)

基本設(shè)計(jì)

服務(wù)場(chǎng)景

單服務(wù)模式下Hystrix的使用測(cè)試

構(gòu)造ThroughputService代表一般的服務(wù)，該服務(wù)能夠在一定時(shí)間內(nèi)返回，同時(shí)，有一個(gè)支持的最大并發(fā)量上限

HystrixCommand封裝ThroughPutService

測(cè)試封裝的HystrixCommand

多服務(wù)和服務(wù)存在依賴的場(chǎng)景測(cè)試

參考

Hystrix中的設(shè)計(jì)哲學(xué)

Hystrix使用總結(jié)

其他特性

相關(guān)閱讀更多精彩內(nèi)容

友情鏈接更多精彩內(nèi)容

色偷偷精品伊人,欧洲久久精品,欧美综合婷婷骚逼,国产AV主播,国产最新探花在线,九色在线视频一区,伊人大交九 欧美,1769亚洲,黄色成人av

Hystrix

配置

使用

超時(shí)降級(jí)

基本設(shè)計(jì)

服務(wù)場(chǎng)景

單服務(wù)模式下Hystrix的使用測(cè)試

構(gòu)造ThroughputService代表一般的服務(wù)，該服務(wù)能夠在一定時(shí)間內(nèi)返回，同時(shí)，有一個(gè)支持的最大并發(fā)量上限

HystrixCommand封裝ThroughPutService

測(cè)試封裝的HystrixCommand

多服務(wù)和服務(wù)存在依賴的場(chǎng)景測(cè)試

參考

Hystrix中的設(shè)計(jì)哲學(xué)

Hystrix使用總結(jié)

其他特性

相關(guān)閱讀更多精彩內(nèi)容

友情鏈接更多精彩內(nèi)容

色偷偷精品伊人,欧洲久久精品,欧美综合婷婷骚逼,国产AV主播,国产最新探花在线,九色在线视频一区,伊人大交九欧美,1769亚洲,黄色成人av

構(gòu)造ThroughputService代表一般的服務(wù)，該服務(wù)能夠在一定時(shí)間內(nèi)返回，同時(shí)，有一個(gè)支持的最大并發(fā)量上限