在docker中運行elasticsearch時go程序無法連接到節點

錯誤信息：

panic: no active connection found: no Elasticsearch node available

在docker中運行es時，默認啟動sniffing 模式，es自動查找節點， 要確保Elasticsearch返回可從容器外部訪問的IP地址。

解決方式為關閉sniffing或者配置es返回的主機地址，參考 https://github.com/olivere/elastic/wiki/Docker

1. 配置elasticsearch

    - 將network.publish_host和network.bind_host配置為可從容器外部訪問的地址

    - 配置network.host （不用再單獨配置network.bind_host 和 network.publish_host）

2. 禁用 sniffing

     elastic.SetSniff(false)

# 查看節點信息，詳細返回參數：Nodes Info
curl -XGET '0.0.0.0:9200/_nodes/http?pretty'
{
  "_nodes" : {
    "total" : 1,
    "successful" : 1,
    "failed" : 0
  },
  "cluster_name" : "escluster",
  "nodes" : {
    "nodename" : {
      "name" : "name",
      "transport_address" : "xxxx:9300",
      "host" : "xxxx",
      "ip" : "xxxx",
      "version" : "6.4.1",
      "build_flavor" : "default",
      "build_type" : "tar",
      "build_hash" : "e36acdb",
      "roles" : [
        "master",
        "data",
        "ingest"
      ],
      "attributes" : {
        "ml.machine_memory" : "16826724352",
        "xpack.installed" : "true",
        "ml.max_open_jobs" : "20",
        "ml.enabled" : "true"
      },
      "http" : {
        "bound_address" : [
          "0.0.0.0:9200"  //http服務綁定的主機地址，配置為可從容器外部訪問的地址
        ],
        "publish_address" : "xxxx:9200", //http客戶端發布的主機地址，配置為可從容器外部訪問的地址
        "max_content_length_in_bytes" : 104857600
      }
    }
  }
}