fix zk service discovery, create parent node if absent

[chickenlj]

Below is exception from dubbo-samples

2021-03-02T05:24:01.2519009Z Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'greeter': FactoryBean threw exception on object creation; nested exception is java.lang.IllegalStateException: registerServiceWatcher create path=/services/demo-provider fail.
2021-03-02T05:24:01.2523291Z 	at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.doGetObjectFromFactoryBean(FactoryBeanRegistrySupport.java:185)
2021-03-02T05:24:01.2528113Z 	at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.getObjectFromFactoryBean(FactoryBeanRegistrySupport.java:103)
2021-03-02T05:24:01.2532435Z 	at org.springframework.beans.factory.support.AbstractBeanFactory.getObjectForBeanInstance(AbstractBeanFactory.java:1646)
2021-03-02T05:24:01.2535888Z 	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:254)
2021-03-02T05:24:01.2538784Z 	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
2021-03-02T05:24:01.2541887Z 	at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:211)
2021-03-02T05:24:01.2545645Z 	at org.springframework.beans.factory.support.DefaultListableBeanFactory.addCandidateEntry(DefaultListableBeanFactory.java:1312)
2021-03-02T05:24:01.2550073Z 	at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:1278)
2021-03-02T05:24:01.2554484Z 	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1097)
2021-03-02T05:24:01.2558700Z 	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1062)
2021-03-02T05:24:01.2563168Z 	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:585)
2021-03-02T05:24:01.2565627Z 	... 35 more
2021-03-02T05:24:01.2566755Z Caused by: java.lang.IllegalStateException: registerServiceWatcher create path=/services/demo-provider fail.
2021-03-02T05:24:01.2569499Z 	at org.apache.dubbo.registry.zookeeper.ZookeeperServiceDiscovery.registerServiceWatcher(ZookeeperServiceDiscovery.java:191)
2021-03-02T05:24:01.2573280Z 	at org.apache.dubbo.registry.zookeeper.ZookeeperServiceDiscovery.lambda$addServiceInstancesChangedListener$6(ZookeeperServiceDiscovery.java:160)
2021-03-02T05:24:01.2575551Z 	at java.lang.Iterable.forEach(Iterable.java:75)
2021-03-02T05:24:01.2578382Z 	at org.apache.dubbo.registry.zookeeper.ZookeeperServiceDiscovery.addServiceInstancesChangedListener(ZookeeperServiceDiscovery.java:160)
2021-03-02T05:24:01.2583462Z 	at org.apache.dubbo.registry.client.EventPublishingServiceDiscovery.addServiceInstancesChangedListener(EventPublishingServiceDiscovery.java:222)
2021-03-02T05:24:01.2588558Z 	at org.apache.dubbo.registry.client.ServiceDiscoveryRegistry.registerServiceInstancesChangedListener(ServiceDiscoveryRegistry.java:357)
2021-03-02T05:24:01.2592495Z 	at org.apache.dubbo.registry.client.ServiceDiscoveryRegistry.subscribeURLs(ServiceDiscoveryRegistry.java:332)
2021-03-02T05:24:01.2595465Z 	at org.apache.dubbo.registry.client.ServiceDiscoveryRegistry.doSubscribe(ServiceDiscoveryRegistry.java:273)
2021-03-02T05:24:01.2598346Z 	at org.apache.dubbo.registry.client.ServiceDiscoveryRegistry.subscribe(ServiceDiscoveryRegistry.java:257)
2021-03-02T05:24:01.2600984Z 	at org.apache.dubbo.registry.ListenerRegistryWrapper.subscribe(ListenerRegistryWrapper.java:105)
2021-03-02T05:24:01.2603367Z 	at org.apache.dubbo.registry.integration.DynamicDirectory.subscribe(DynamicDirectory.java:151)
2021-03-02T05:24:01.2605980Z 	at org.apache.dubbo.registry.integration.RegistryProtocol.doCreateInvoker(RegistryProtocol.java:498)
2021-03-02T05:24:01.2610123Z 	at org.apache.dubbo.registry.integration.InterfaceCompatibleRegistryProtocol.getServiceDiscoveryInvoker(InterfaceCompatibleRegistryProtocol.java:65)
2021-03-02T05:24:01.2614911Z 	at org.apache.dubbo.registry.client.migration.MigrationInvoker.refreshServiceDiscoveryInvoker(MigrationInvoker.java:291)
2021-03-02T05:24:01.2619078Z 	at org.apache.dubbo.registry.client.migration.MigrationInvoker.migrateToServiceDiscoveryInvoker(MigrationInvoker.java:112)
2021-03-02T05:24:01.2622692Z 	at org.apache.dubbo.registry.client.migration.MigrationRuleHandler.doMigrate(MigrationRuleHandler.java:60)
2021-03-02T05:24:01.2625706Z 	at org.apache.dubbo.registry.client.migration.MigrationRuleListener.onRefer(MigrationRuleListener.java:103)
2021-03-02T05:24:01.2628626Z 	at org.apache.dubbo.registry.integration.RegistryProtocol.interceptInvoker(RegistryProtocol.java:471)
2021-03-02T05:24:01.2631177Z 	at org.apache.dubbo.registry.integration.RegistryProtocol.doRefer(RegistryProtocol.java:457)
2021-03-02T05:24:01.2633438Z 	at org.apache.dubbo.registry.integration.RegistryProtocol.refer(RegistryProtocol.java:451)
2021-03-02T05:24:01.2635742Z 	at org.apache.dubbo.rpc.protocol.ProtocolListenerWrapper.refer(ProtocolListenerWrapper.java:72)
2021-03-02T05:24:01.2638024Z 	at org.apache.dubbo.rpc.protocol.ProtocolFilterWrapper.refer(ProtocolFilterWrapper.java:80)
2021-03-02T05:24:01.2640182Z 	at org.apache.dubbo.qos.protocol.QosProtocolWrapper.refer(QosProtocolWrapper.java:73)
2021-03-02T05:24:01.2641839Z 	at org.apache.dubbo.rpc.Protocol$Adaptive.refer(Protocol$Adaptive.java)
2021-03-02T05:24:01.2643265Z 	at org.apache.dubbo.config.ReferenceConfig.createProxy(ReferenceConfig.java:367)
2021-03-02T05:24:01.2644924Z 	at org.apache.dubbo.config.ReferenceConfig.init(ReferenceConfig.java:305)
2021-03-02T05:24:01.2646406Z 	at org.apache.dubbo.config.ReferenceConfig.get(ReferenceConfig.java:204)
2021-03-02T05:24:01.2648050Z 	at org.apache.dubbo.config.spring.ReferenceBean.getObject(ReferenceBean.java:68)
2021-03-02T05:24:01.2651436Z 	at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.doGetObjectFromFactoryBean(FactoryBeanRegistrySupport.java:178)

[codecov-io]

Codecov Report

Merging #7304 (4ac42ff) into master (51d5a88) will increase coverage by 0.07%.
The diff coverage is 0.00%.

@@             Coverage Diff              @@
##             master    #7304      +/-   ##
============================================
+ Coverage     58.92%   59.00%   +0.07%     
  Complexity      462      462              
============================================
  Files          1044     1044              
  Lines         42455    42472      +17     
  Branches       6222     6228       +6     
============================================
+ Hits          25017    25060      +43     
+ Misses        14619    14608      -11     
+ Partials       2819     2804      -15     

Impacted Files	Coverage Δ	Complexity Δ
.../registry/zookeeper/ZookeeperServiceDiscovery.java	33.33% <0.00%> (ø)	0.00 <0.00> (ø)
...pache/dubbo/registry/support/AbstractRegistry.java	78.14% <0.00%> (-2.97%)	0.00% <0.00%> (ø%)
...rg/apache/dubbo/rpc/protocol/AbstractExporter.java	60.00% <0.00%> (-1.12%)	0.00% <0.00%> (ø%)
...ache/dubbo/rpc/protocol/AbstractProxyProtocol.java	58.75% <0.00%> (-0.51%)	0.00% <0.00%> (ø%)
.../apache/dubbo/config/bootstrap/DubboBootstrap.java	42.02% <0.00%> (-0.10%)	0.00% <0.00%> (ø%)
...rg/apache/dubbo/common/timer/HashedWheelTimer.java	79.38% <0.00%> (ø)	0.00% <0.00%> (ø%)
.../rpc/cluster/router/condition/ConditionRouter.java	68.75% <0.00%> (ø)	0.00% <0.00%> (ø%)
...apache/dubbo/rpc/protocol/dubbo/DubboExporter.java	100.00% <0.00%> (ø)	0.00% <0.00%> (ø%)
...apache/dubbo/rpc/protocol/injvm/InjvmExporter.java	100.00% <0.00%> (ø)	0.00% <0.00%> (ø%)
.../dubbo/rpc/protocol/grpc/DubboHandlerRegistry.java	0.00% <0.00%> (ø)	0.00% <0.00%> (ø%)
... and 21 more

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[AlbumenJ]

LGTM.