soul网关源码解析-Hystrix插件

最新推荐文章于 2021-02-06 19:45:38 发布

原创最新推荐文章于 2021-02-06 19:45:38 发布 · 175 阅读

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该博客介绍了如何在系统中配置并使用Hystrix进行流量限流和熔断操作。首先在插件管理中启用插件配置，然后设置限流规则。当请求触发限流时，会执行HystrixCommand和HystrixCommandOnThread的相关方法，这两个类实现了Hystrix的命令模式，用于处理限流和熔断。在执行过程中，如果熔断器打开，会记录错误日志并执行回退逻辑。

首先在插件管理中开启插件配置.
在这里插入图片描述
然后再配置需要加入限流的信息.

然后我们再请求的话如果有其他情况就会出现以下信息

好下面我们看下限流插件方法的执行

    @Override
    protected Mono<Void> doExecute(final ServerWebExchange exchange, final SoulPluginChain chain, final SelectorData selector, final RuleData rule) {
    //获取请求信息
        final SoulContext soulContext = exchange.getAttribute(Constants.CONTEXT);
        assert soulContext != null;
                //获取限流的信息
        final HystrixHandle hystrixHandle = GsonUtils.getInstance().fromJson(rule.getHandle(), HystrixHandle.class);
        if (StringUtils.isBlank(hystrixHandle.getGroupKey())) {
            hystrixHandle.setGroupKey(Objects.requireNonNull(soulContext).getModule());
        }
        if (StringUtils.isBlank(hystrixHandle.getCommandKey())) {
            hystrixHandle.setCommandKey(Objects.requireNonNull(soulContext).getMethod());
        }
        //限流的方式(信号量和线程)
        Command command = fetchCommand(hystrixHandle, exchange, chain);
        return Mono.create(s -> {
            Subscription sub = command.fetchObservable().subscribe(s::success,
                    s::error, s::success);
            s.onCancel(sub::unsubscribe);
            if (command.isCircuitBreakerOpen()) {
                log.error("hystrix execute have circuitBreaker is Open! groupKey:{},commandKey:{}", hystrixHandle.getGroupKey(), hystrixHandle.getCommandKey());
            }
        }).doOnError(throwable -> {
            log.error("hystrix execute exception:", throwable);
            exchange.getAttributes().put(Constants.CLIENT_RESPONSE_RESULT_TYPE, ResultEnum.ERROR.getName());
            chain.execute(exchange);
        }).then();
    }

我们分别看下2个方法.
HystrixCommand 和 HystrixCommandOnThread

public class HystrixCommand extends HystrixObservableCommand<Void> implements Command {
    
    private final ServerWebExchange exchange;

    private final SoulPluginChain chain;

    private final URI callBackUri;
    
    /**
     * Instantiates a new Http command.
     *
     * @param setter      the setter
     * @param exchange    the exchange
     * @param chain       the chain
     * @param callBackUri the call back uri
     */
    public HystrixCommand(final Setter setter,
                   final ServerWebExchange exchange,
                   final SoulPluginChain chain,
                   final String callBackUri) {
        super(setter);
        this.exchange = exchange;
        this.chain = chain;
        this.callBackUri = UriUtils.createUri(callBackUri);
    }

    @Override
    protected Observable<Void> construct() {
        return RxReactiveStreams.toObservable(chain.execute(exchange));
    }

    @Override
    protected Observable<Void> resumeWithFallback() {
        return RxReactiveStreams.toObservable(doFallback());
    }

    private Mono<Void> doFallback() {
        if (isFailedExecution()) {
            log.error("hystrix execute have error: ", getExecutionException());
        }
        final Throwable exception = getExecutionException();
        return doFallback(exchange, exception);
    }

    @Override
    public Observable<Void> fetchObservable() {
        return this.toObservable();
    }

    @Override
    public URI getCallBackUri() {
        return callBackUri;
    }
}

@Slf4j
public class HystrixCommandOnThread extends HystrixCommand<Mono<Void>> implements Command {
    
    private final ServerWebExchange exchange;

    private final SoulPluginChain chain;

    private final URI callBackUri;
    
    /**
     * Instantiates a new Http command.
     *
     * @param setter      the setter
     * @param exchange    the exchange
     * @param chain       the chain
     * @param callBackUri the call back uri
     */
    public HystrixCommandOnThread(final HystrixCommand.Setter setter,
                          final ServerWebExchange exchange,
                          final SoulPluginChain chain,
                          final String callBackUri) {
        super(setter);
        this.exchange = exchange;
        this.chain = chain;
        this.callBackUri = UriUtils.createUri(callBackUri);
    }

    @Override
    protected Mono<Void> run() {
        RxReactiveStreams.toObservable(chain.execute(exchange)).toBlocking().subscribe();
        return Mono.empty();
    }

    @Override
    protected Mono<Void> getFallback() {
        if (isFailedExecution()) {
            log.error("hystrix execute have error: ", getExecutionException());
        }
        final Throwable exception = getExecutionException();
        return doFallback(exchange, exception);
    }

    @Override
    public Observable<Void> fetchObservable() {
        return RxReactiveStreams.toObservable(this.execute());
    }

    @Override
    public URI getCallBackUri() {
        return callBackUri;
    }
}