golang操作elasticsearch的实现

1、前提

1.1 docker 安装elasticsearch

查询elasticsearch 版本

docker search elasticsearch

将对应的版本拉到本地

docker.elastic.co/elasticsearch/elasticsearch:7.3.0

创建一个网络

docker network create esnet

启动容器

docker run --name es -p 9200:9200 -p 9300:9300 --network esnet -e "discovery.type=single-node" bdaab402b220

1.2这里过后就可以去写go代码 为了直观搞了个可视化工具 ElisticHD 这里使用docker 部署

docker run -p 9800:9800 -d --link es:demo --network esnet -e "discovery.type=single-node" containerize/elastichd

可以试一下界面还是很美观的

2、golang 实现elasticsearch 简单的增删改查

直接上代码：

package main

import (
  "context"
  "encoding/json"
  "fmt"
  "github.com/olivere/elastic/v7"
  "reflect"
)

var client *elastic.Client
var host = "http://ip:port"

type Employee struct {
  FirstName string  `json:"first_name"`
  LastName string  `json:"last_name"`
  Age    int   `json:"age"`
  About   string  `json:"about"`
  Interests []string `json:"interests"`
}

//初始化
func init() {
  //errorlog := log.New(os.Stdout, "APP", log.LstdFlags)
  var err error
      //这个地方有个小坑 不加上elastic.SetSniff(false) 会连接不上 
  client, err = elastic.NewClient(elastic.SetSniff(false), elastic.SetURL(host))
  if err != nil {
    panic(err)
  }
  _,_,err = client.Ping(host).Do(context.Background())
  if err != nil {
    panic(err)
  }
  //fmt.Printf("Elasticsearch returned with code %d and version %s\n", code, info.Version.Number)

  _,err = client.ElasticsearchVersion(host)
  if err != nil {
    panic(err)
  }
  //fmt.Printf("Elasticsearch version %s\n", esversion)

}

/*下面是简单的CURD*/

//创建
func create() {

  //使用结构体
  e1 := Employee{"Jane", "Smith", 32, "I like to collect rock albums", []string{"music"}}
  put1, err := client.Index().
    Index("megacorp").
    Type("employee").
    Id("1").
    BodyJson(e1).
    Do(context.Background())
  if err != nil {
    panic(err)
  }
  fmt.Printf("Indexed tweet %s to index s%s, type %s\n", put1.Id, put1.Index, put1.Type)

  //使用字符串
  e2 := `{"first_name":"John","last_name":"Smith","age":25,"about":"I love to go rock climbing","interests":["sports","music"]}`
  put2, err := client.Index().
    Index("megacorp").
    Type("employee").
    Id("2").
    BodyJson(e2).
    Do(context.Background())
  if err != nil {
    panic(err)
  }
  fmt.Printf("Indexed tweet %s to index s%s, type %s\n", put2.Id, put2.Index, put2.Type)

  e3 := `{"first_name":"Douglas","last_name":"Fir","age":35,"about":"I like to build cabinets","interests":["forestry"]}`
  put3, err := client.Index().
    Index("megacorp").
    Type("employee").
    Id("3").
    BodyJson(e3).
    Do(context.Background())
  if err != nil {
    panic(err)
  }
  fmt.Printf("Indexed tweet %s to index s%s, type %s\n", put3.Id, put3.Index, put3.Type)

}


//查找
func gets() {
  //通过id查找
  get1, err := client.Get().Index("megacorp").Type("employee").Id("2").Do(context.Background())
  if err != nil {
    panic(err)
  }
  if get1.Found {
    fmt.Printf("Got document %s in version %d from index %s, type %s\n", get1.Id, get1.Version, get1.Index, get1.Type)
    var bb Employee
    err:=json.Unmarshal(get1.Source,&bb)
    if err!=nil{
      fmt.Println(err)
    }
    fmt.Println(bb.FirstName)
    fmt.Println(string(get1.Source))
  }

}
//
//删除
func delete() {

  res, err := client.Delete().Index("megacorp").
    Type("employee").
    Id("1").
    Do(context.Background())
  if err != nil {
    println(err.Error())
    return
  }
  fmt.Printf("delete result %s\n", res.Result)
}
//
//修改
func update() {
  res, err := client.Update().
    Index("megacorp").
    Type("employee").
    Id("2").
    Doc(map[string]interface{}{"age": 88}).
    Do(context.Background())
  if err != nil {
    println(err.Error())
  }
  fmt.Printf("update age %s\n", res.Result)

}
//
////搜索
func query() {
  var res *elastic.SearchResult
  var err error
  //取所有
  res, err = client.Search("megacorp").Type("employee").Do(context.Background())
  printEmployee(res, err)

  //字段相等
  q := elastic.NewQueryStringQuery("last_name:Smith")
  res, err = client.Search("megacorp").Type("employee").Query(q).Do(context.Background())
  if err != nil {
    println(err.Error())
  }
  printEmployee(res, err)



  //条件查询
  //年龄大于30岁的
  boolQ := elastic.NewBoolQuery()
  boolQ.Must(elastic.NewMatchQuery("last_name", "smith"))
  boolQ.Filter(elastic.NewRangeQuery("age").Gt(30))
  res, err = client.Search("megacorp").Type("employee").Query(q).Do(context.Background())
  printEmployee(res, err)

  //短语搜索 搜索about字段中有 rock climbing
  matchPhraseQuery := elastic.NewMatchPhraseQuery("about", "rock climbing")
  res, err = client.Search("megacorp").Type("employee").Query(matchPhraseQuery).Do(context.Background())
  printEmployee(res, err)

  //分析 interests
  aggs := elastic.NewTermsAggregation().Field("interests")
  res, err = client.Search("megacorp").Type("employee").Aggregation("all_interests", aggs).Do(context.Background())
  printEmployee(res, err)

}
//
////简单分页
func list(size,page int) {
  if size < 0 || page < 1 {
    fmt.Printf("param error")
    return
  }
  res,err := client.Search("megacorp").
    Type("employee").
    Size(size).
    From((page-1)*size).
    Do(context.Background())
  printEmployee(res, err)

}
//
//打印查询到的Employee
func printEmployee(res *elastic.SearchResult, err error) {
  if err != nil {
    print(err.Error())
    return
  }
  var typ Employee
  for _, item := range res.Each(reflect.TypeOf(typ)) { //从搜索结果中取数据的方法
    t := item.(Employee)
    fmt.Printf("%#v\n", t)
  }
}

func main() {
  create()
  delete()
  update()
  gets()
  query()
  list(2,1)
}

有一个小坑要注意在代码中已经注释了，如果没有添加就会有下面错误

no active connection found: no Elasticsearch node available

解决

Docker No Elastic Node Aviable

关闭sniff模式；或者设置es的地址为 publish_address 地址

代码设置 sniff 为false