Canal-adapter1.1.14 最新版本安裝的過程中出現的NullPointerException異常

系統環境

CentOS Linux release 7.7.1908
Canal 1.1.14

問題現象

2020-06-08 13:39:48.019 [Thread-2] ERROR c.a.o.canal.adapter.launcher.loader.CanalAdapterService - ## something goes wrong whe
n starting up the canal client adapters:
java.lang.NullPointerException: null
        at com.alibaba.otter.canal.adapter.launcher.loader.CanalAdapterLoader.init(CanalAdapterLoader.java:95)
        at com.alibaba.otter.canal.adapter.launcher.loader.CanalAdapterService.init(CanalAdapterService.java:58)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleElement.invoke(InitDes
troyAnnotationBeanPostProcessor.java:365)
        at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleMetadata.invokeInitMet
hods(InitDestroyAnnotationBeanPostProcessor.java:308)
        at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessBeforeInitialization
(InitDestroyAnnotationBeanPostProcessor.java:135)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitializ
ation(AbstractAutowireCapableBeanFactory.java:422)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapable
BeanFactory.java:1694)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBe
anFactory.java:579)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBean
Factory.java:501)
        at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$1(AbstractBeanFactory.java:353)
        at org.springframework.cloud.context.scope.GenericScope$BeanLifecycleWrapper.getBean(GenericScope.java:390)

問題解決

1. 翻看源碼，參見參考資料3，定位到CanalAdapterLoader.java:95
2. 檢查Canal-adapter application.yml

原來的配置：

canal.conf:
  mode: kafka
  canalServerHost: 127.0.0.1:11116
  zookeeperHosts: 172.16.97.56:2181,172.16.97.78:2181,172.16.97.28:2181
  mqServers: 172.16.97.56:9092,172.16.97.78:9092,172.16.97.28:9092 #or rocketmq
  flatMessage: true
  srcDataSources:
    defaultDS:
      url: jdbc:mysql://xxxx:3306/b
illcore?useUnicode=true&characterEncoding=UTF-8
      username: xxx
      password: xxx

canalAdapters:
  - instance: xxx_test # canal instance Name or mq topic name
    groups:
    - groupId: g1
      outerAdapters:
      - name: logger
      - name: hbase

修改後配置：

canal.conf:
  mode: kafka
  canalServerHost: 127.0.0.1:11116
  zookeeperHosts: 172.16.97.56:2181,172.16.97.78:2181,172.16.97.28:2181
  mqServers: 172.16.97.56:9092,172.16.97.78:9092,172.16.97.28:9092 #or rocketmq
  flatMessage: true
  srcDataSources:
    defaultDS:
      url: jdbc:mysql://x.x.x.x:3306/b
illcore?useUnicode=true&characterEncoding=UTF-8
      username: xxx
      password: xxx

  canalAdapters:
    - instance: xxx_test # canal instance Name or mq topic name
      groups:
      - groupId: g1
        outerAdapters:
        - name: logger
        - name: hbase
        
          

最終的問題是canalAdapters的縮進問題，導致無法讀取到canalAdapters配置

參考資料

1. https://www.cnblogs.com/lukairui/p/12461339.html
2. https://github.com/alibaba/canal/issues/1077
3. https://github.com/alibaba/canal/blob/canal-1.1.4/client-adapter/launcher/src/main/java/com/alibaba/otter/canal/adapter/launcher/loader/CanalAdapterLoader.java