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Spring Cloud Alibaba Nacos 之灰度发布(思路分享)

今天给大家分享一篇我在学习Nacos想用它做灰度发布的思路分享。

什么是灰度发布请看如下链接： baike.baidu.com/item/灰度发布/7…

那么进入正题，在netflix全家桶相继凉凉后，Ribbon组件确一直坚挺包括在Spring Cloud Alibaba Nacos中也在使用。其实要基于Nacos做灰度发布，也是在Ribbon上做手脚。

第一步扩展Metadata Predicate

public abstract class DiscoveryEnabledPredicate extends AbstractServerPredicate {


    @Override
    public boolean apply(@Nullable PredicateKey input) {
    	//由于NacosServer继承了Ribbon的Server,那么扩展成其他配置中心同理
        return input != null
                && input.getServer() instanceof NacosServer
                && apply((NacosServer) input.getServer());
    }

    protected abstract boolean apply(NacosServer nacosServer);
}
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public class MetadataAwarePredicate extends DiscoveryEnabledPredicate{

    
    @Override
    protected boolean apply(NacosServer nacosServer) {
    	//根据客户端传入的版本号进行过滤，此处可自行设计扩展
        HttpServletRequest request = ((ServletRequestAttributes)RequestContextHolder
                .getRequestAttributes()).getRequest();
        String versionNo = request.getHeader("version");
        Map<String,String> versionMap = new HashMap<>();
        versionMap.put("version",versionNo);
        final Set<Map.Entry<String,String>> attributes =
                Collections.unmodifiableSet(versionMap.entrySet());
        final Map<String,String> metadata = nacosServer.getInstance().getMetadata();
        return metadata.entrySet().containsAll(attributes);
    }
}
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第二步扩展Metadata Rule

public abstract class DiscoveryEnabledRule extends PredicateBasedRule {

    private final CompositePredicate predicate;

    public DiscoveryEnabledRule(DiscoveryEnabledPredicate  discoveryEnabledPredicate) {
        Assert.notNull(discoveryEnabledPredicate, "Parameter 'discoveryEnabledPredicate' can't be null");
        this.predicate = createCompositePredicate(discoveryEnabledPredicate,new AvailabilityPredicate(this,null));
    }



    @Override
    public AbstractServerPredicate getPredicate() {
        return this.predicate;
    }

    private CompositePredicate createCompositePredicate(DiscoveryEnabledPredicate discoveryEnabledPredicate,
                                                        AvailabilityPredicate availabilityPredicate) {
        return CompositePredicate.withPredicates(discoveryEnabledPredicate, availabilityPredicate)
                .build();
    }
}
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public class MetadataAwareRule extends DiscoveryEnabledRule{


    public MetadataAwareRule(){
        this(new MetadataAwarePredicate());
    }

    public MetadataAwareRule(DiscoveryEnabledPredicate predicate) {
        super(predicate);
    }
}
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第三步丢进Spring容器

@Configuration
public class RibbonDiscoveryRuleAutoConfiguration {

    @Bean
    public DiscoveryEnabledRule metadataAwareRule(){
        return new MetadataAwareRule();
    }
}
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