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

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