canal-adapter消费dynamicTopic问题

[jackzlz]

canal配置dynamicTopic后实现单表单topic，canal-adapter应该怎么配置来实现每个表消费对应的topic呢 ？如果配置canalAdapters多个instance，看了下代码会导致ESAdapter重复初始化

[jackzlz]

目前的方案是： 如果多个mq同步到同一个es时，保证es只初始化一次即可。即保证adapter的init方法只执行一次。 改动点：

1. ExtensionLoader增加isExtensionExists方法

   public boolean isExtensionExists(String name, String key) {
   
       String extKey = name + "-" + StringUtils.trimToEmpty(key);
       Holder<Object> holder = cachedInstances.get(extKey);
       return holder != null && holder.get() != null;
   
   }

2. CanalAdapterLoaderloadAdapter的时候判断

3. canalAdapters配置

   canalAdapters:
   - instance: schema_table1 # canal instance Name or mq topic name
     groups:
       - groupId: g1
         outerAdapters:
           - name: logger
           - name: es7
             key: es7
             hosts: 127.0.0.1:9200 # 127.0.0.1:9200 for rest mode
             properties:
               mode: rest # or rest
               security.auth: elastic:12345678 #  only used for rest mode
               scheme: https
               certificate.type: pem
               certificate.path: /crt/elasticsearch-test.crt
   - instance: schema_table2 # canal instance Name or mq topic name
     groups:
       - groupId: g1
         outerAdapters:
           - name: logger
           - name: es7
             key: es7
   - instance: schema_table3 # canal instance Name or mq topic name
     groups:
       - groupId: g1
         outerAdapters:
           - name: logger
           - name: es7
             key: es7

配置的时候保证outerAdapters配置相同的name和key，这样同一个name+key只会初始化一次。而es的连接信息只需要配置第一个，因为是按顺序加载的

[jackzlz]

上面的写法有问题。改成了下面的：

[jackzlz]

最终采用的方案是，多个表就配置多个instance，因为多个表配置同一个esconnection偶尔报错。ElasticsearchException[Elasticsearch exception [type=version_conflict_engine_exception,

  canalAdapters:
    - instance: schema_table1 # canal instance Name or mq topic name
      groups:
        - groupId: g1
          outerAdapters:
            - name: logger
            - name: es7
              key: table1
              hosts: 127.0.0.1:9200 # 127.0.0.1:9200 for rest mode
              properties:
                mode: rest # or rest
                security.auth: elastic:12345678 #  only used for rest mode
                scheme: https
                certificate.type: pem
                certificate.path: /crt/elasticsearch-test.crt
    - instance: schema_table2 # canal instance Name or mq topic name
      groups:
        - groupId: g1
          outerAdapters:
            - name: logger
            - name: es7
              key: table2
              hosts: 127.0.0.1:9200 # 127.0.0.1:9200 for rest mode
              properties:
                mode: rest # or rest
                security.auth: elastic:12345678 #  only used for rest mode
                scheme: https
                certificate.type: pem
                certificate.path: /crt/elasticsearch-test.crt
    - instance: schema_table3 # canal instance Name or mq topic name
      groups:
        - groupId: g1
          outerAdapters:
            - name: logger
            - name: es7
              key: table3
              hosts: 127.0.0.1:9200 # 127.0.0.1:9200 for rest mode
              properties:
                mode: rest # or rest
                security.auth: elastic:12345678 #  only used for rest mode
                scheme: https
                certificate.type: pem
                certificate.path: /crt/elasticsearch-test.crt