Golang查询Elasticsearch
本文主要讲 golang 连接 es 的常用操作
1.下载依赖库
$ go get github.com/olivere/elastic操作代码如下：
es.go
package es
import (
"context"
"fmt"
"github.com/olivere/elastic"
"strconv"
"time"
)
var host = []string{
"http://10.42.0.121:9200/",
"http://10.42.0.122:9200/",
"http://10.42.0.123:9200/",
}
var client *elastic.Client
//初始化
func init() {
var err error
client, err = elastic.NewClient(elastic.SetURL(host...))
if err != nil {
fmt.Printf("create client failed, err: %v", err)
}
}
//ping 连接测试
func PingNode() {
start := time.Now()
info, code, err := client.Ping(host[0]).Do(context.Background())
if err != nil {
fmt.Printf("ping es failed, err: %v", err)
}
duration := time.Since(start)
fmt.Printf("cost time: %v\n", duration)
fmt.Printf("Elasticsearch returned with code %d and version %s\n", code, info.Version.Number)
}
//校验 index 是否存在
func IndexExists(index ...string) bool {
exists, err := client.IndexExists(index...).Do(context.Background())
if err != nil {
fmt.Printf("%v\n", err)
}
return exists
}
//创建 index
func CreateIndex(index, mapping string) bool {
result, err := client.CreateIndex(index).BodyString(mapping).Do(context.Background())
if err != nil {
fmt.Printf("create index failed, err: %v\n", err)
}
return result.Acknowledged
}
//删除 index
func DelIndex(index... string) bool {
response, err := client.DeleteIndex(index...).Do(context.Background())
if err != nil {
fmt.Printf("delete index failed, err: %v\n", err)
}
return response.Acknowledged
}
//批量插入
func Batch(index string, type_ string, datas... interface{}) {
bulkRequest := client.Bulk()
for i, data := range datas {
doc := elastic.NewBulkIndexRequest().Index(index).Type(type_).Id(strconv.Itoa(i)).Doc(data)
bulkRequest = bulkRequest.Add(doc)
}
response, err := bulkRequest.Do(context.TODO())
if err != nil {
panic(err)
}
failed := response.Failed()
iter := len(failed)
fmt.Printf("error: %v, %v\n", response.Errors, iter)
}
//获取指定 Id 的文档
func GetDoc(index, id string) []byte {
temp := client.Get().Index(index).Id(id)
get, err := temp.Do(context.Background())
if err != nil {
panic(err)
}
if get.Found {
fmt.Printf("Got document %s in version %d from index %s, type %s\n", get.Id, get.Version, get.Index, get.Type)
}
source, err := get.Source.MarshalJSON()
if err != nil {
fmt.Printf("byte convert string failed, err: %v", err)
}
return source
}
//term 查询
func TermQuery(index, type_, fieldName, fieldValue string) *elastic.SearchResult {
query := elastic.NewTermQuery(fieldName, fieldValue)
//_ = elastic.NewQueryStringQuery(fieldValue) //关键字查询
searchResult, err := client.Search().
Index(index).Type(type_).
Query(query).
From(0).Size(10).
Pretty(true).
Do(context.Background())
if err != nil {
panic(err)
}
fmt.Printf("query cost %d millisecond.\n", searchResult.TookInMillis)
return searchResult
}
func Search(index, type_ string) *elastic.SearchResult {
boolQuery := elastic.NewBoolQuery()
boolQuery.Must(elastic.NewMatchQuery("user", "Jame10"))
boolQuery.Filter(elastic.NewRangeQuery("age").Gt("30"))
searchResult, err := client.Search(index).
Type(type_).Query(boolQuery).Pretty(true).Do(context.Background())
if err != nil {
panic(err)
}
return searchResult
}
func AggsSearch(index, type_ string) {
minAgg := elastic.NewMinAggregation().Field("age")
rangeAgg := elastic.NewRangeAggregation().Field("age").AddRange(0,30).AddRange(30,60).Gt(60)
build := client.Search(index).Type(type_).Pretty(true)
minResult, err := build.Aggregation("minAgg", minAgg).Do(context.Background())
rangeResult, err := build.Aggregation("rangeAgg", rangeAgg).Do(context.Background())
if err != nil {
panic(err)
}
minAggRes, _ := minResult.Aggregations.Min("minAgg")
fmt.Printf("min: %v\n", *minAggRes.Value)
rangeAggRes, _ := rangeResult.Aggregations.Range("rangeAgg")
for _, item := range rangeAggRes.Buckets {
fmt.Printf("key: %s, value: %v\n", item.Key, item.DocCount)
}
}
测试类 es_test.go
package es
import (
"encoding/json"
"fmt"
"github.com/olivere/elastic"
"reflect"
"testing"
"time"
)
type Tweet struct {
User string `json:"user"`
Age int `json:"age"`
Message string `json:"message"`
Retweets int `json:"retweets"`
Image string `json:"image,omitempty"`
Created time.Time `json:"created,omitempty"`
Tags []string `json:"tags,omitempty"`
Location string `json:"location,omitempty"`
Suggest *elastic.SuggestField `json:"suggest_field,omitempty"`
}
var mapping = `{
"settings":{
"number_of_shards": 3,
"number_of_replicas": 1
},
"mappings":{
"doc":{
"properties":{
"user":{
"type":"keyword"
},
"age":{
"type": "integer"
},
"message":{
"type":"text",
"store": true,
"fielddata": true
},
"image":{
"type":"keyword"
},
"created":{
"type":"date"
},
"tags":{
"type":"keyword"
},
"location":{
"type":"geo_point"
},
"suggest_field":{
"type":"completion"
}
}
}
}
}`
func TestPingNode(t *testing.T) {
PingNode()
}
func TestIndexExists(t *testing.T) {
result := IndexExists("car_source", "test")
fmt.Println("all index exists: ", result)
}
func TestDeleteIndex(t *testing.T) {
result := DelIndex("twitter")
fmt.Println("all index deleted: ", result)
}
func TestCreateIndex(t *testing.T) {
result := CreateIndex("twitter", mapping)
fmt.Println("mapping created: ", result)
}
func TestBatch(t *testing.T) {
tweet1 := Tweet{User: "Jame1",Age: 23, Message: "Take One", Retweets: 1, Created: time.Now()}
tweet2 := Tweet{User: "Jame2",Age: 32, Message: "Take Two", Retweets: 0, Created: time.Now()}
tweet3 := Tweet{User: "Jame3",Age: 32, Message: "Take Three", Retweets: 0, Created: time.Now()}
Batch("twitter", "doc", tweet1, tweet2, tweet3)
}
func TestGetDoc(t *testing.T) {
var tweet Tweet
data := GetDoc("twitter", "1")
if err := json.Unmarshal(data, &tweet); err == nil {
fmt.Printf("data: %v\n", tweet)
}
}
func TestTermQuery(t *testing.T) {
var tweet Tweet
result := TermQuery("twitter", "doc", "user", "Take Two")
//获得数据, 方法一
for _, item := range result.Each(reflect.TypeOf(tweet)) {
if t, ok := item.(Tweet); ok {
fmt.Printf("tweet : %v\n", t)
}
}
//获得数据, 方法二
fmt.Println("num of raws: ", result.Hits.TotalHits)
if result.Hits.TotalHits > 0 {
for _, hit := range result.Hits.Hits {
err := json.Unmarshal(*hit.Source, &tweet)
if err != nil {
fmt.Printf("source convert json failed, err: %v\n", err)
}
fmt.Printf("data: %v\n", tweet)
}
}
}
func TestSearch(t *testing.T) {
result := Search("twitter", "doc")
var tweet Tweet
for _, item := range result.Each(reflect.TypeOf(tweet)) {
if t, ok := item.(Tweet); ok {
fmt.Printf("tweet : %v\n", t)
}
}
}
func TestAggsSearch(t *testing.T) {
AggsSearch("twitter", "doc")
}