深入OpenFeign超时与重试机制:源码剖析与实战优化,构建高可靠服务调用链路

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publicclassFeignClientFactoryBeanimplementsFactoryBean<Object>,InitializingBean,ApplicationContextAware{// ...@OverridepublicObject getObject()throwsException{return getTarget();}<T> T getTarget() {FeignContext context = applicationContext.getBean(FeignContext.class);Feign.Builder builder = feign(context);if(!StringUtils.hasText(url)){// ... 加载全局配置return(T) loadBalance(builder, context,newHardCodedTarget<>(type, name, url));}// ... 加载局部配置}// ...}

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publicclassDefaultimplementsClient{@OverridepublicResponse execute(Request request,Options options)throwsIOException{HttpURLConnection connection = convertAndSend(request, options);return convertResponse(connection).toBuilder().request(request).build();}privateHttpURLConnection convertAndSend(Request request,Options options)throwsIOException{ URL url =new URL(request.url());HttpURLConnection connection =(HttpURLConnection) url.openConnection();// 设置连接超时 connection.setConnectTimeout(options.connectTimeoutMillis());// 设置读取超时 connection.setReadTimeout(options.readTimeoutMillis());// ... 其他配置return connection;}}

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publicstaticclassOptions{privatefinalint connectTimeoutMillis;privatefinalint readTimeoutMillis;privatefinalboolean followRedirects;publicOptions(int connectTimeoutMillis,int readTimeoutMillis){this(connectTimeoutMillis, readTimeoutMillis,true);}publicOptions(int connectTimeoutMillis,int readTimeoutMillis,boolean followRedirects){this.connectTimeoutMillis = connectTimeoutMillis;this.readTimeoutMillis = readTimeoutMillis;this.followRedirects = followRedirects;    }    // getter方法}

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public interface Retryer extends Cloneable {    void continueOrPropagate(RetryableException e);    Retryer clone();}

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public class DefaultRetryer implements Retryer {    private final int maxAttempts;    private final long period;    private final long maxPeriod;    int attempt;    long sleptForMillis;    public DefaultRetryer() {        this(100, SECONDS.toMillis(1), 5);    }    @Override    public void continueOrPropagate(RetryableException e) {        if (attempt++ >= maxAttempts) {            throw e;        }        long interval = nextMaxInterval();        try {            Thread.sleep(interval);        } catch (InterruptedException ignored) {            Thread.currentThread().interrupt();            throw e;        }        sleptForMillis += interval;    }    long nextMaxInterval() {        long interval = (long) (period * Math.pow(1.5, attempt - 1));        return interval > maxPeriod ? maxPeriod : interval;    }}

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@Overridepublic Object invoke(Object[] argv) throws Throwable {    RequestTemplate template = buildTemplateFromArgs.create(argv);    Options options = findOptions(argv);    Retryer retryer = this.retryer.clone();    while (true) {        try {            return executeAndDecode(template, options);        } catch (RetryableException e) {            try {                retryer.continueOrPropagate(e);            } catch (RetryableException th) {                throw th.getCause() != null ? th.getCause() : th;            }            logger.logRetry(metadata.configKey(), logLevel);            continue;        }    }}

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@FeignClient(name = "user-service", configuration = UserServiceFeignConfig.class)public interface UserServiceClient {    // ...}@Configurationpublic class UserServiceFeignConfig {    @Bean    public Request.Options feignOptions() {        return new Request.Options(5000, 10000);    }}