dubbo 整合spring boot 的时候死锁

[yunxiyi]

dubbo 整合spring boot，在启动的时候发生死锁。在MulticastRegistry 在registered的时候。创建invoker过程中 ，会将MonitorFacotry注入MonitorFilter中。在取MonitorFacotry值时，首先会去SpiExtensionFactory 获取值，如果这里没有获取到；会到SpringExtensionFactory获取，SpringExtensionFactory 这个时候会触发ObjectFactory提前初始化。

    protected Object getSingleton(String beanName, boolean allowEarlyReference) {
        Object singletonObject = this.singletonObjects.get(beanName);
        if (singletonObject == null && isSingletonCurrentlyInCreation(beanName)) {
            synchronized (this.singletonObjects) {
                singletonObject = this.earlySingletonObjects.get(beanName);
                if (singletonObject == null && allowEarlyReference) {
                    ObjectFactory<T> singletonFactory = this.singletonFactories.get(beanName);
                    if (singletonFactory != null) {
                        singletonObject = singletonFactory.getObject();
                        this.earlySingletonObjects.put(beanName, singletonObject);
                        this.singletonFactories.remove(beanName);
                    }
                }
            }
        }
        return singletonObject;
    }

这里会锁住所有对象，而被controller注解的，就是其中一员。

@Controller("/data")
public class DataController {

    @Reference(check = false)
    DemoService demoService;

    @PostConstruct
    public void init() {
        demoService.sayHello("hello world");
    }

    @RequestMapping("/info")
    @ResponseBody
    public Object info() {
        Map<String, Object> map = new HashMap<>();

        map.put("message", "134");
        return map;
    }

}

这个时候就可能产生死锁。因为main 线程可能正在执行创建bean
被 SPI 注解的接口不应该从SpringExtensionFactory 中获取代理对象。
所以这里修改了SpringExtensionFactory 的getExtension 的方法。

public <T> T getExtension(Class<T> type, String name) {

        //SPI never get from spring bean factory
        if (type.isInterface() && type.isAnnotationPresent(SPI.class)) {
            ExtensionLoader<T> loader = ExtensionLoader.getExtensionLoader(type);
            if (!loader.getSupportedExtensions().isEmpty()) {
                return loader.getAdaptiveExtension();
            }
            return null;
        }

        for (ApplicationContext context : contexts) {
            if (context.containsBean(name)) {
                Object bean = context.getBean(name);
                if (type.isInstance(bean)) {
                    return (T) bean;
                }
            }
        }

        logger.warn("No spring extension(bean) named:" + name + ", try to find an extension(bean) of type " + type.getName());

        for (ApplicationContext context : contexts) {
            try {
                return context.getBean(type);
            } catch (NoUniqueBeanDefinitionException multiBeanExe) {
                throw multiBeanExe;
            } catch (NoSuchBeanDefinitionException noBeanExe) {
                if (logger.isDebugEnabled()) {
                    logger.debug("Error when get spring extension(bean) for type:" + type.getName(), noBeanExe);
                }
            }
        }

        logger.warn("No spring extension(bean) named:" + name + ", type:" + type.getName() + " found, stop get bean.");

        return null;
    }

这个是demo的地址，dubbo provider 使用的是dubbo 2.7.0-SNAPSHOT 中的dubbo-demo-provider。

[chenlei65368]

既然改成这样了为什么要打警告 WARN c.a.d.c.s.e.SpringExtensionFactory:63] [DUBBO] No spring extension(bean) named:defaultCompiler, try to find an extension(bean) of type java.lang.String

[chenlei65368]

SpringExtensionFactory:77] [DUBBO] No spring extension(bean) named:defaultCompiler, type:java.lang.String found, stop get bean. 如果避免这个警告？

[MingJunDuan]

dubbo版本2.6.4，如何避免这个警告呢？