[ENHANCEMENT]: flusher 报错不明显

[ltx0633]

Concisely describe the proposed feature

flusher_elasticsearch 报错不明显

Describe the solution you'd like (if any)

增加清晰的日志输出

Additional comments
当域名不存在的时候，日志中没有明显的错误

    flushers:
      - Type: flusher_stdout
        OnlyStdout: true
      - Type: flusher_elasticsearch
        Addresses:
          - "https://test-es.xxx.com"
        Index: log_%{+yyyyMMdd}
        Authentication:
          PlainText:
            Username: elastic
            Password: xxxxx

[liangry]

记得以前有个文件叫：logtail_plugin.LOG，现在怎么没了？

[liangry]

记得以前有个文件叫：logtail_plugin.LOG，现在怎么没了？

搞错了，两个问题没有关系，这个文件也在

[messixukejia]

Concisely describe the proposed feature

flusher_elasticsearch 报错不明显

Describe the solution you'd like (if any)

增加清晰的日志输出

Additional comments 当域名不存在的时候，日志中没有明显的错误

    flushers:
      - Type: flusher_stdout
        OnlyStdout: true
      - Type: flusher_elasticsearch
        Addresses:
          - "https://test-es.xxx.com"
        Index: log_%{+yyyyMMdd}
        Authentication:
          PlainText:
            Username: elastic
            Password: xxxxx

如果有需要可以提交PR完善下。