Golang操作elasticsearch(一)

Golang操作elasticsearch

• 使用第三方包:olivere github。总结一下olivere操作ES的常用功能,方便查阅。
• 说明:以下例子用到的es index:"test", es type:"test", es address: "http://10.1.1.1:9200"

1. 新建es client

   func ESClient() (client *elastic.Client,err error){
    file := "./log.log"
    logFile, _ := os.OpenFile(file, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0766) // 应该判断error,此处简略
    cfg := []elastic.ClientOptionFunc{
    elastic.SetURL("http://10.1.1.1:9200"),
    elastic.SetSniff(false),
    elastic.SetInfoLog(log.New(logFile, "ES-INFO: ", 0)),
    elastic.SetTraceLog(log.New(logFile, "ES-TRACE: ", 0)),
    elastic.SetErrorLog(log.New(logFile, "ES-ERROR: ", 0)),
    }
    client,err =elastic.NewClient(cfg ...)
    return
   }

2. 查看某文档是否存在,给定文档ID查询

   func isExists(id string)bool{
    client,_ := ESClient()
    defer client.Stop()
    exist,_ := client.Exists().Index("test").Type("test").Id(id).Do(context.Background())
    if !exist{
    log.Println("ID may be incorrect! ",id)
    return false
    }
    return true
   }

3. 获取某文档的内容

   func(doc *myDocument) Get(id string){
    client ,_:= ESClient()
    defer client.Stop() 
    if !isExists(id){
    return
    }
    esResponse,err := client.Get().Index("test").Type("test").Id(id).Do(context.Background())
    if err != nil {
    // Handle Error
    return
    }
    json.Unmarshal(*esResponse.Source,&doc)
   }

4. 新增文档

   func(doc *myDocument) Add(id string){
    client ,_:= ESClient()
    defer client.Stop() 
    if !isExists(id){
    return
    }
    client.Index().Index("test").Type("test").Id(id).BodyJson(doc).Do(context.Background())
   }

5. 批量新增

   func BulkAdd(docs []myDocument){
    bulkRequest := seriesClient.Bulk()
    client ,_:= ESClient()
    defer client.Stop()
    for _,doc := range docs{
    esRequest := elastic.NewBulkIndexRequest().Index("test").Type("test").Id(id).Doc(doc)
    bulkRequest = bulkRequest.Add(esRequest)
    }
    bulkRequest.Do(context.Background())
   }

6. 更新文档

   func Update(updateField *map[string]interface{},id string){
    client ,_:= ESClient()
    defer client.Stop()
    if !isExists(id){
    return
    }
    _,err:=client.Update().Index("test").Type("test").Id(id).Doc(updateField).Do(context.Background())
    if err != nil{
    //Handle Error
    }
   }

7. 删除文档

   func Delete(id string){
    client ,_:= ESClient()
    defer client.Stop()
    if !isExists(id){
    return
    }
    _,err:=client.Delete().Index("test").Type("test").Id(id).Do(context.Background())
    if err != nil{
    //Handle Error
    }
   }

8. 搜索文档(搜索是ES非常引以为傲的功能,以下示例是相对复杂的查询条件,需将查询结果排序,按页返回)

   func Search(criteria *SearchCriteria)(docs []myDocument){
    client ,_:= ESClient()
    defer client.Stop()
    query := elastic.NewBoolQuery()
    query = query.Must(elastic.NewTermQuery("category",criteria.Category))
    query=query.Must(elastic.NewMatchQuery("title",criteria.Title))
    query=query.Must(elastic.NewRangeQuery("update_timestamp").Gte(criteria.UpdateTime))
    esResponse,_ :=client.Search().Index("test").Type("test").
    Query(query).Sort(criteria.Sort,criteria.Order=="ASC"||criteria.Order=="asc").
    From(criteria.Offset).Size(criteria.Limit).Do(context.Background())
    for _,value:= range esResponse.Hits.Hits{
    var doc *myDocument
    json.Unmarshal(*value.Source,&doc)
    docs = append(docs,doc)
    }
    return
   }
   type SearchCriteria struct{
    Category string `json:"category"`
    Limit int `json:"limit"`
    Offset int `json:"offset"`
    Title string `json:"title"`
    UpdateTime int64 `json:"update_timestamp"`
    Order string `json:"order"`
    Sort string `json:"sort"`
   }