go对elasticsearch的增删改查

环境

elasticsearch 6.8 (6.x版本应该都没问题)

go客户端sdk: github.com/elastic/go-elasticsearch/v6

其实自己封装api也行，反正elasticsearch对外交互的协议是restful接口

注意点

发起的请求，如果成功了，一定要记得关闭返回Response的Body,否则会占用一个连接。

全局变量和函数

var c *elasticsearch.Client

func init() {
    var err error
    config := elasticsearch.Config{}
    config.Addresses = []string{"http://127.0.0.1:9200"}
    c, err = elasticsearch.NewClient(config)
    checkError(err)
}

func checkError(err error) {
    if err != nil {
        fmt.Println(err)
        os.Exit(1)
    }   
}

创建索引

func createIndex() {
    body := map[string]interface{}{
        "mappings": map[string]interface{}{
            "test_type": map[string]interface{}{
                "properties": map[string]interface{}{
                    "str": map[string]interface{}{
                        "type": "keyword",   // 表示这个字段不分词
                    },  
                },  
            },  
        },  
    }
    jsonBody, _ := json.Marshal(body)
    req := esapi.IndicesCreateRequest{
        Index: "test_index",
        Body:  bytes.NewReader(jsonBody),
    }
    res, err := req.Do(context.Background(), c)
    checkError(err)
    defer res.Body.Close()
    fmt.Println(res.String())
}

[200 OK] {"acknowledged":true,"shards_acknowledged":true,"index":"test_index"}

删除索引

func deleteIndex() {
    req := esapi.IndicesDeleteRequest{
        Index: []string{"test_index"},
    }
    res, err := req.Do(context.Background(), c)
    checkError(err)
    defer res.Body.Close()
    fmt.Println(res.String())
}

[200 OK] {"acknowledged":true}

往索引插入数据

插入单条数据

func insertSingle() {
    body := map[string]interface{}{
        "num": 0,
        "v":   0,
        "str": "test",
    }
    jsonBody, _ := json.Marshal(body)

    req := esapi.CreateRequest{    // 如果是esapi.IndexRequest则是插入/替换
        Index:        "test_index",
        DocumentType: "test_type",
        DocumentID:   "test_1",
        Body:         bytes.NewReader(jsonBody),
    }
    res, err := req.Do(context.Background(), c)
    checkError(err)
    defer res.Body.Close()
    fmt.Println(res.String())
}

[201 Created] {"_index":"test_index","_type":"test_type","_id":"test_1","_version":1,"result":"created","_shards":{"total":2,"successful":1,"failed":0},"_seq_no":0,"_primary_term":1}

批量插入(很明显，也可以批量做其他操作)

func insertBatch() {
    var bodyBuf bytes.Buffer
    for i := 2; i < 10; i++ {
        createLine := map[string]interface{}{
            "create": map[string]interface{}{
                "_index": "test_index",
                "_id":    "test_" + strconv.Itoa(i),
                "_type":  "test_type",
            },
        }
        jsonStr, _ := json.Marshal(createLine)
        bodyBuf.Write(jsonStr)
        bodyBuf.WriteByte('
')

        body := map[string]interface{}{
            "num": i % 3,
            "v":   i,
            "str": "test" + strconv.Itoa(i),
        }
        jsonStr, _ = json.Marshal(body)
        bodyBuf.Write(jsonStr)
        bodyBuf.WriteByte('
')
    }

    req := esapi.BulkRequest{
        Body: &bodyBuf,
    }
    res, err := req.Do(context.Background(), c)
    checkError(err)
    defer res.Body.Close()
    fmt.Println(res.String())
}

[200 OK] {"took":31,"errors":false,"items":[{"create":{"_index":"test_index","_type":"test_type","_id":"test_2","_version":1,"result":"created","_shards":{"total":2,"successful":1,"failed":0},"_seq_no":0,"_primary_term":1,"status":201}},{"create":{"_index":"test_index","_type":"test_type","_id":"test_3","_version":1,"result":"created","_shards":{"total":2,"successful":1,"failed":0},"_seq_no":1,"_primary_term":1,"status":201}},{"create":{"_index":"test_index","_type":"test_type","_id":"test_4","_version":1,"result":"created","_shards":{"total":2,"successful":1,"failed":0},"_seq_no":2,"_primary_term":1,"status":201}},{"create":{"_index":"test_index","_type":"test_type","_id":"test_5","_version":1,"result":"created","_shards":{"total":2,"successful":1,"failed":0},"_seq_no":0,"_primary_term":1,"status":201}},{"create":{"_index":"test_index","_type":"test_type","_id":"test_6","_version":1,"result":"created","_shards":{"total":2,"successful":1,"failed":0},"_seq_no":1,"_primary_term":1,"status":201}},{"create":{"_index":"test_index","_type":"test_type","_id":"test_7","_version":1,"result":"created","_shards":{"total":2,"successful":1,"failed":0},"_seq_no":1,"_primary_term":1,"status":201}},{"create":{"_index":"test_index","_type":"test_type","_id":"test_8","_version":1,"result":"created","_shards":{"total":2,"successful":1,"failed":0},"_seq_no":2,"_primary_term":1,"status":201}},{"create":{"_index":"test_index","_type":"test_type","_id":"test_9","_version":1,"result":"created","_shards":{"total":2,"successful":1,"failed":0},"_seq_no":3,"_primary_term":1,"status":201}}]}

查询

通过sql查询

func selectBySql() {
    query := map[string]interface{}{
        "query": "select count(*) as cnt, max(v) as value, num from test_index where num > 0 group by num",
    }
    jsonBody, _ := json.Marshal(query)
    req := esapi.XPackSQLQueryRequest{
        Body: bytes.NewReader(jsonBody),
    }
    res, err := req.Do(context.Background(), c)
    checkError(err)
    defer res.Body.Close()
    fmt.Println(res.String())
}

[200 OK] {"columns":[{"name":"cnt","type":"long"},{"name":"value","type":"long"},{"name":"num","type":"long"}],"rows":[[2,7.0,1],[3,8.0,2]],"cursor":"q47zAgFjAQp0ZXN0X2luZGV4igEBAQljb21wb3NpdGUHZ3JvdXBieQEDbWF4Ajg2AAD/AQF2AAAA/wAA/wEAAjc4AQNudW0AAAH/AADoBwEKAQI3OAIAAAAAAAAAAgACAQAAAAABAP////8PAAAAAAEFcmFuZ2U/gAAAAANudW0BAAAAAP8AAAAAAAAAAAAAAAABWgMAAgIAAAAAAAH/////DwMBawI3OAEBWgABbQI4NgV2YWx1ZQAAAVoBawI3OAABWgABBw=="}

通过Search Api查询

func selectBySearch() {
    query := map[string]interface{}{
        "query": map[string]interface{}{
            "bool": map[string]interface{}{
                "filter": map[string]interface{}{
                    "range": map[string]interface{}{
                        "num": map[string]interface{}{
                            "gt": 0,
                        },  
                    },  
                },  
            },  
        },  
        "size": 0,
        "aggs": map[string]interface{}{
            "num": map[string]interface{}{
                "terms": map[string]interface{}{
                    "field": "num",
                    //"size":  1,
                },  
                "aggs": map[string]interface{}{
                    "max_v": map[string]interface{}{
                        "max": map[string]interface{}{
                            "field": "v",
                        },  
                    },  
                },  
            },  
        },  
    }   
    jsonBody, _ := json.Marshal(query)
    
    req := esapi.SearchRequest{
        Index:        []string{"test_index"},
        DocumentType: []string{"test_type"},
        Body:         bytes.NewReader(jsonBody),
    }   
    res, err := req.Do(context.Background(), c)
    checkError(err)
    defer res.Body.Close()
    fmt.Println(res.String())
}

[200 OK] {"took":10,"timed_out":false,"_shards":{"total":5,"successful":5,"skipped":0,"failed":0},"hits":{"total":5,"max_score":0.0,"hits":[]},"aggregations":{"num":{"doc_count_error_upper_bound":0,"sum_other_doc_count":0,"buckets":[{"key":2,"doc_count":3,"max_v":{"value":8.0}},{"key":1,"doc_count":2,"max_v":{"value":7.0}}]}}}

但是elasticsearch对聚合查询分页并不是很友好，基本上都是得自己手动分页。

局部更新(批量更新略)

根据id更新

func updateSingle() {          
    body := map[string]interface{}{
        "doc": map[string]interface{}{
            "v": 100,     
        },
    }                     
    jsonBody, _ := json.Marshal(body)
    req := esapi.UpdateRequest{
        Index:        "test_index",
        DocumentType: "test_type",
        DocumentID:   "test_1",
        Body:         bytes.NewReader(jsonBody),
    }                     
                          
    res, err := req.Do(context.Background(), c)
    checkError(err)       
    defer res.Body.Close()
    fmt.Println(res.String())                
}

[200 OK] {"_index":"test_index","_type":"test_type","_id":"test_1","_version":2,"result":"updated","_shards":{"total":2,"successful":1,"failed":0},"_seq_no":3,"_primary_term":1}

除了doc方式之外，还有script方式

根据条件更新

func updateByQuery() {
    body := map[string]interface{}{
        "script": map[string]interface{}{
            "lang": "painless",
            "source": `
                ctx._source.v = params.value;
            `,
            "params": map[string]interface{}{
                "value": 101,
            },
        },
        "query": map[string]interface{}{
            "match_all": map[string]interface{}{},
        },
    } 
    jsonBody, _ := json.Marshal(body)
    req := esapi.UpdateByQueryRequest{
        Index: []string{"test_index"},
        Body:  bytes.NewReader(jsonBody),
    } 
    res, err := req.Do(context.Background(), c)
    checkError(err)
    defer res.Body.Close()
    fmt.Println(res.String())
}

[200 OK] {"took":109,"timed_out":false,"total":9,"updated":9,"deleted":0,"batches":1,"version_conflicts":0,"noops":0,"retries":{"bulk":0,"search":0},"throttled_millis":0,"requests_per_second":-1.0,"throttled_until_millis":0,"failures":[]}

删除

根据id删除

func deleteSingle() {
    req := esapi.DeleteRequest{
        Index:        "test_index",
        DocumentType: "test_type",
        DocumentID:   "test_1",
    }   

    res, err := req.Do(context.Background(), c)
    checkError(err)
    defer res.Body.Close()
    fmt.Println(res.String())
}	

[200 OK] {"_index":"test_index","_type":"test_type","_id":"test_1","_version":6,"result":"deleted","_shards":{"total":2,"successful":1,"failed":0},"_seq_no":7,"_primary_term":1}

根据条件删除

func deleteByQuery() { 
    body := map[string]interface{}{
        "query": map[string]interface{}{
            "match_all": map[string]interface{}{},
        },
    } 
    jsonBody, _ := json.Marshal(body)
    req := esapi.DeleteByQueryRequest{
        Index: []string{"test_index"},
        Body:  bytes.NewReader(jsonBody),
    } 
    res, err := req.Do(context.Background(), c)
    checkError(err)
    defer res.Body.Close()
    fmt.Println(res.String())
}

[200 OK] {"took":17,"timed_out":false,"total":9,"deleted":9,"batches":1,"version_conflicts":0,"noops":0,"retries":{"bulk":0,"search":0},"throttled_millis":0,"requests_per_second":-1.0,"throttled_until_millis":0,"failures":[]}