Go操作Elasticsearch

安装ES

拉取es到本地

docker pull 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

安装ElisticHD

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

下载依赖库

 go get github.com/olivere/elastic/v7  

操作案例

创建索引

package main

import (
	"context"
	"fmt"
	"github.com/olivere/elastic"
)

var client *elastic.Client

var host = "http://192.168.43.176:9200"


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
", code, info.Version.Number)

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

//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
", 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
", 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
", put3.Id, put3.Index, put3.Type)
}

func main()  {
	create()
}

查找

package main

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

var client *elastic.Client

var host = "http://192.168.43.176:9200"

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
", code, info.Version.Number)

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

//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
", 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))
	}
}

func main() {
	//create()
	gets()
}

删除

//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
", res.Result)
}

func main() {
	//create()
	//gets()
	delete()
}

修改

//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
", res.Result)

}

func main() {
	//create()
	//gets()
	//delete()
	update()
}

搜索

////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
", t)
	}
}


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