go操作elasticsearch示例 go操作elasticsearch示例

【go操作elasticsearch示例】这里我使用elasticsearch官方给的go语言包（go-elasticsearch）
go-elasticsearch向前兼容，这意味着客户端支持与更大或同等次要版本的 Elasticsearch 通信。Elasticsearch 语言客户端仅向后兼容默认发行版，不提供任何保证。

包：https://github.com/elastic/go...
Elasticsearch 权威指南：https://www.elastic.co/guide/...

环境介绍：

版本 Elasticsearch:v7.15

安装
go.mod 文件中添加

require github.com/elastic/go-elasticsearch/v8 main

或者

git clone --branch main https://github.com/elastic/go-elasticsearch.git $GOPATH/src/github.com/elastic/go-elasticsearch

示例：
新建 es.go 存入 es目录

package esimport ( "bytes" "context" "encoding/json" "fmt" "github.com/elastic/go-elasticsearch/v8" "github.com/elastic/go-elasticsearch/v8/esapi" "log" "net/http" )var EsClient *elasticsearch.Clientfunc init() {cfg := elasticsearch.Config{ Addresses: []string{ "http://localhost:9200", }, } var err error EsClient, err = elasticsearch.NewClient(cfg) if err != nil { log.Fatalln("Failed to connect to es") } } func failOnError(err error, msg string) { if err != nil { log.Fatalf("%s: %s", msg, err) } }// idx 为空，默认随机唯一字符串 func Index(index, idx string, doc map[string]interface{}) { //index:="my_index_name_v1" res, err := EsClient.Info() fmt.Println(res, err) if err != nil { log.Fatalf("Error getting response: %s", err) } var buf bytes.Buffer //doc := map[string]interface{}{ //"title":"中国", //"content": "中国早日统一台湾", //"time":time.Now().Unix(), //"date":time.Now(), //} if err = json.NewEncoder(&buf).Encode(doc); err != nil { fmt.Println(err, "Error encoding doc") return } res, err = EsClient.Index( index,// Index name &buf,// Document body EsClient.Index.WithDocumentID(idx), // Document ID // Document ID EsClient.Index.WithRefresh("true"), // Refresh ) //res, err = EsClient.Create(index, idx, &buf) if err != nil { fmt.Println(err, "Error create response") } defer res.Body.Close() fmt.Println(res.String()) log.Println(res) }//struct 类型允许使用更实际的方法，您可以在其中创建一个新结构，将请求配置作为字段，并使用上下文和客户端作为参数调用 Do() 方法： func IndexEspi(index, idx string, doc map[string]interface{}) { //index:="my_index_name_v1" res, err := EsClient.Info() fmt.Println(res, err) if err != nil { log.Fatalf("Error getting response: %s", err) } var buf bytes.Buffer //doc := map[string]interface{}{ //"title":"中国", //"content": "中国早日统一台湾", //"time":time.Now().Unix(), //"date":time.Now(), //} if err = json.NewEncoder(&buf).Encode(doc); err != nil { fmt.Println(err, "Error encoding doc") return }req := esapi.IndexRequest{ Index:index,// Index name Body:&buf,// Document body DocumentID: idx,// Document ID Refresh:"true", // Refresh }res, err = req.Do(context.Background(), EsClient) if err != nil { log.Fatalf("Error getting response: %s", err) } defer res.Body.Close() fmt.Println(res.String()) log.Println(res) } func Search(index string, query map[string]interface{}) { res, err := EsClient.Info() if err != nil { fmt.Println(err, "Error getting response") } //fmt.Println(res.String()) // search - highlight var buf bytes.Buffer //query := map[string]interface{}{ //"query": map[string]interface{}{ //"match": map[string]interface{}{ //"title": title, //}, //}, //"highlight": map[string]interface{}{ //"pre_tags":[]string{""}, //"post_tags": []string{""}, //"fields": map[string]interface{}{ //"title": map[string]interface{}{}, //}, //}, //} if err := json.NewEncoder(&buf).Encode(query); err != nil { fmt.Println(err, "Error encoding query") } // Perform the search request. res, err = EsClient.Search( EsClient.Search.WithContext(context.Background()), EsClient.Search.WithIndex(index), EsClient.Search.WithBody(&buf), EsClient.Search.WithTrackTotalHits(true), EsClient.Search.WithFrom(0), EsClient.Search.WithSize(10), EsClient.Search.WithSort("time:desc"), EsClient.Search.WithPretty(), ) if err != nil { fmt.Println(err, "Error getting response") } defer res.Body.Close() fmt.Println(res.String()) }//删除 index 根据索引名 idfunc Delete(index, idx string) { //index:="my_index_name_v1" res, err := EsClient.Info() fmt.Println(res, err) if err != nil { log.Fatalf("Error getting response: %s", err) } res, err = EsClient.Delete( index, // Index name idx,// Document ID EsClient.Delete.WithRefresh("true"), ) if err != nil { fmt.Println(err, "Error create response") } defer res.Body.Close() fmt.Println(res.String()) log.Println(res) } func DeleteByQuery(index []string, query map[string]interface{}) { res, err := EsClient.Info() if err != nil { fmt.Println(err, "Error getting response") } //fmt.Println(res.String()) // search - highlight var buf bytes.Buffer //query := map[string]interface{}{ //"query": map[string]interface{}{ //"match": map[string]interface{}{ //"title": title, //}, //}, //}, //} if err := json.NewEncoder(&buf).Encode(query); err != nil { fmt.Println(err, "Error encoding query") } // Perform the search request. res, err = EsClient.DeleteByQuery( index, &buf, ) if err != nil { fmt.Println(err, "Error getting response") } defer res.Body.Close() fmt.Println(res.String())} func SearchEsapiSql(query map[string]interface{}) { jsonBody, _ := json.Marshal(query) req := esapi.SQLQueryRequest{Body: bytes.NewReader(jsonBody)} res, _ := req.Do(context.Background(), EsClient) defer res.Body.Close() fmt.Println(res.String()) } func SearchHttp(method, url string, query map[string]interface{}) { jsonBody, _ := json.Marshal(query) req, _ := http.NewRequest(method, url, bytes.NewReader(jsonBody)) req.Header.Add("Content-type", "application/json") res, err := EsClient.Perform(req) if err != nil { return } defer res.Body.Close() buf := new(bytes.Buffer) buf.ReadFrom(res.Body) fmt.Println(buf.String()) }

新建 main.go

package main import "demo/es" func main() { index := "my_index_name_v4" //创建索引并设置映射 //query := map[string]interface{}{ //"mappings": map[string]interface{}{ //"properties": map[string]interface{}{ //"title": map[string]interface{}{ //"type": "text", //}, //"content": map[string]interface{}{ //"type": "text", //}, //"location": map[string]interface{}{ //"type": "geo_point", //}, //"time": map[string]interface{}{ //"type": "long", //}, //"date": map[string]interface{}{ //"type": "date", //}, //"age": map[string]interface{}{ //"type": "keyword", //}, //}, //}, //} //url := index //注意映射信息不能更新 //es.SearchHttp("PUT", url, query)//添加或修改文档，没有索引创建 //doc := map[string]interface{}{ //"title":"你好", //"content":"中国美丽的城市", //"location": "41.015, -75.011", //"time":time.Now().Unix(), //"date":time.Now(), //"age":20, //}//es.Index(index, "", doc) //es.IndexEspi(index, "idx5", doc) //删除索引 //es.Delete(index, "idx3") //query := map[string]interface{}{ //"query": map[string]interface{}{ //"match": map[string]interface{}{ //"title": "vvvvv我爱你！!!!", //}, //}, //} //indexArr := []string{index} //es.DeleteByQuery(indexArr, query) ////搜索单个字段 //query := map[string]interface{}{ //"query": map[string]interface{}{ //"match": map[string]interface{}{ //"title": "我爱你中国", //}, //}, //"highlight": map[string]interface{}{ //"pre_tags":[]string{""}, //"post_tags": []string{""}, //"fields": map[string]interface{}{ //"title": map[string]interface{}{}, //}, //}, //}//搜索多个字段 //query := map[string]interface{}{ //"query": map[string]interface{}{ //"multi_match": map[string]interface{}{ //"query":"中国", //"fields": []string{"title", "content"}, //}, //}, //"highlight": map[string]interface{}{ //"pre_tags":[]string{""}, //"post_tags": []string{""}, //"fields": map[string]interface{}{ //"title": map[string]interface{}{}, //}, //}, //} //提高某个字段权重，可以使用 ^ 字符语法为单个字段提升权重，在字段名称的末尾添加 ^boost ，其中 boost 是一个浮点数： //query := map[string]interface{}{ //"query": map[string]interface{}{ //"multi_match": map[string]interface{}{ //"query":"中国", //"fields": []string{"title", "content^2"}, //}, //}, //"highlight": map[string]interface{}{ //"pre_tags":[]string{""}, //"post_tags": []string{""}, //"fields": map[string]interface{}{ //"title": map[string]interface{}{}, //}, //}, //}//显示所有的 //query := map[string]interface{}{ //"query": map[string]interface{}{ //"match_all": map[string]interface{}{}, //}, //} //es.Search(index, query) //地理距离过滤器（ geo_distance ）以给定位置为圆心画一个圆，来找出那些地理坐标落在其中的文档： //query := map[string]interface{}{ //"query": map[string]interface{}{ //"bool": map[string]interface{}{ //"must": map[string]interface{}{ //"match_all": map[string]interface{}{}, // 这里不设置其他查询条件，所以匹配全部文档 //}, //"filter": map[string]interface{}{ //"geo_distance": map[string]interface{}{ //"distance": "100km", //"location": map[string]interface{}{ //"lat": 40.715, //"lon": -73.988, //}, //}}, //}, //}, //"sort": map[string]interface{}{ // 设置排序条件 //"_geo_distance": map[string]interface{}{ //_geo_distance代表根据距离排序 //"location": map[string]interface{}{ //根据location存储的经纬度计算距离。 //"lat": 40.715,//当前纬度 //"lon": -73.988, //当前经度 //}, //"order": "asc", // asc 表示升序，desc 表示降序 //}}, //} //es.Search(index, query) //精确值查询 //query := map[string]interface{}{ //"query": map[string]interface{}{ //"match": map[string]interface{}{ //"age": "20", //}, //},//} //es.Search(index, query) //范围查询 //通过range实现范围查询，类似SQL语句中的>, >=, <, <=表达式。 //gte范围参数 - 等价于>= //lte范围参数 - 等价于 <= //范围参数可以只写一个，例如：仅保留 "gte": 10，则代表 FIELD字段 >= 10 //query := map[string]interface{}{ //"query": map[string]interface{}{ //"range": map[string]interface{}{ //"age": map[string]interface{}{ //"gte": "19", //"lte": "20", //}, //}, //}, //} //es.Search(index, query) //组合查询如果需要编写类似SQL的Where语句，组合多个字段的查询条件，可以使用bool语句。 //"must": [], // must条件，类似SQL中的and, 代表必须匹配条件 //"must_not": [], // must_not条件，跟must相反，必须不匹配条件 //"should": [] // should条件，类似SQL中or, 代表匹配其中一个条件 query := map[string]interface{}{ "query": map[string]interface{}{ "bool": map[string]interface{}{ "must": []map[string]interface{}{ { "match": map[string]interface{}{ "age": "19", }, }, { "match": map[string]interface{}{ "title": "中国", }, }, }, }, }, } es.Search(index, query)//使用mysql的方式来请求 //query := map[string]interface{}{ //"query": "select title from " + index + " where title like '%中国%'", //这里使用mysql的方式来请求，非常简单，符合开发习惯，简化es入门门槛，支持order，支持Limit，那么排序和分页就自己写好了 //} //query := map[string]interface{}{ //"query": "select title from " + index + " where title = '中国'", //这里使用mysql的方式来请求，非常简单，符合开发习惯，简化es入门门槛，支持order，支持Limit，那么排序和分页就自己写好了 //} //es.SearchEsapiSql(query)//测试分词 //query := map[string]interface{}{ //"analyzer": "ik_smart", //智能分词用：ik_smart，最大化分词用：ik_max_word //"text":"中国华人民", //} //url := index + "_analyze?pretty=true"//query := map[string]interface{}{ //"query": map[string]interface{}{ //"match": map[string]interface{}{ //"title": "我爱你中国", //}, //}, //"highlight": map[string]interface{}{ //"pre_tags":[]string{""}, //"post_tags": []string{""}, //"fields": map[string]interface{}{ //"title": map[string]interface{}{}, //}, //}, //} //url := index + "/_search"//es.SearchHttp("GET", url, query)}

参考资料
https://github.com/elastic/go...
https://www.tizi365.com/archi...
https://www.elastic.co/guide/...
links