Golang使用Elasticsearch [zt]
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2020-06-12 21:05:02 发表
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关键字: golang
https://studygolang.com/articles/28869
Golang使用Elasticsearch
创建es.go文件
根据elasticsearch版本拉取对应的go包：github.com/elastic/go-elasticsearch
API文档：https://pkg.go.dev/github.com/elastic/go-elasticsearch/v6@v6.8.5/esapi?tab=doc
package es
import (
"bytes"
"context"
"encoding/json"
"fmt"
"github.com/elastic/go-elasticsearch/v6"
"log"
)
func failOnError(err error, msg string) {
if err != nil {
log.Fatalf("%s: %s", msg, err)
}
}
Index 在索引中创建或更新文档
索引不存在的情况下，会自动创建索引。
默认的_type（类型）是_doc，下面是指定doc类型创建添加的。
func Index() {
addresses := []string{"http://127.0.0.1:9200", "http://127.0.0.1:9201"}
config := elasticsearch.Config{
Addresses: addresses,
Username: "",
Password: "",
CloudID: "",
APIKey: "",
}
// new client
es, err := elasticsearch.NewClient(config)
failOnError(err, "Error creating the client")
// Index creates or updates a document in an index
var buf bytes.Buffer
doc := map[string]interface{}{
"title": "你看到外面的世界是什么样的？",
"content": "外面的世界真的很精彩",
}
if err := json.NewEncoder(&buf).Encode(doc); err != nil {
failOnError(err, "Error encoding doc")
}
res, err := es.Index("demo", &buf, es.Index.WithDocumentType("doc"))
if err != nil {
failOnError(err, "Error Index response")
}
defer res.Body.Close()
fmt.Println(res.String())
}
Search 搜索
func Search() {
addresses := []string{"http://127.0.0.1:9200", "http://127.0.0.1:9201"}
config := elasticsearch.Config{
Addresses: addresses,
Username: "",
Password: "",
CloudID: "",
APIKey: "",
}
// new client
es, err := elasticsearch.NewClient(config)
failOnError(err, "Error creating the client")
// info
res, err := es.Info()
failOnError(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": "中国",
},
},
"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 {
failOnError(err, "Error encoding query")
}
// Perform the search request.
res, err = es.Search(
es.Search.WithContext(context.Background()),
es.Search.WithIndex("demo"),
es.Search.WithBody(&buf),
es.Search.WithTrackTotalHits(true),
es.Search.WithPretty(),
)
if err != nil {
failOnError(err, "Error getting response")
}
defer res.Body.Close()
fmt.Println(res.String())
}
DeleteByQuery 通过匹配条件删除文档
func DeleteByQuery() {
addresses := []string{"http://127.0.0.1:9200", "http://127.0.0.1:9201"}
config := elasticsearch.Config{
Addresses: addresses,
Username: "",
Password: "",
CloudID: "",
APIKey: "",
}
// new client
es, err := elasticsearch.NewClient(config)
failOnError(err, "Error creating the client")
// DeleteByQuery deletes documents matching the provided query
var buf bytes.Buffer
query := map[string]interface{}{
"query": map[string]interface{}{
"match": map[string]interface{}{
"title": "外面",
},
},
}
if err := json.NewEncoder(&buf).Encode(query); err != nil {
failOnError(err, "Error encoding query")
}
index := []string{"demo"}
res, err := es.DeleteByQuery(index, &buf)
if err != nil {
failOnError(err, "Error delete by query response")
}
defer res.Body.Close()
fmt.Println(res.String())
}
Delete通过_id删除文档
func Delete() {
addresses := []string{"http://127.0.0.1:9200", "http://127.0.0.1:9201"}
config := elasticsearch.Config{
Addresses: addresses,
Username: "",
Password: "",
CloudID: "",
APIKey: "",
}
// new client
es, err := elasticsearch.NewClient(config)
failOnError(err, "Error creating the client")
// Delete removes a document from the index
res, err := es.Delete("demo", "POcKSHIBX-ZyL96-ywQO")
if err != nil {
failOnError(err, "Error delete by id response")
}
defer res.Body.Close()
fmt.Println(res.String())
}
Create 添加文档（需要指定_id，_id已存在返回409）
func Create() {
addresses := []string{"http://127.0.0.1:9200", "http://127.0.0.1:9201"}
config := elasticsearch.Config{
Addresses: addresses,
Username: "",
Password: "",
CloudID: "",
APIKey: "",
}
// new client
es, err := elasticsearch.NewClient(config)
failOnError(err, "Error creating the client")
// Create creates a new document in the index.
// Returns a 409 response when a document with a same ID already exists in the index.
var buf bytes.Buffer
doc := map[string]interface{}{
"title": "你看到外面的世界是什么样的？",
"content": "外面的世界真的很精彩",
}
if err := json.NewEncoder(&buf).Encode(doc); err != nil {
failOnError(err, "Error encoding doc")
}
res, err := es.Create("demo", "esd", &buf, es.Create.WithDocumentType("doc"))
if err != nil {
failOnError(err, "Error create response")
}
defer res.Body.Close()
fmt.Println(res.String())
}
Get 通过id获取文档
func Get() {
addresses := []string{"http://127.0.0.1:9200", "http://127.0.0.1:9201"}
config := elasticsearch.Config{
Addresses: addresses,
Username: "",
Password: "",
CloudID: "",
APIKey: "",
}
// new client
es, err := elasticsearch.NewClient(config)
failOnError(err, "Error creating the client")
res, err := es.Get("demo", "esd")
if err != nil {
failOnError(err, "Error get response")
}
defer res.Body.Close()
fmt.Println(res.String())
}
Update 通过_id更新文档
func Update() {
addresses := []string{"http://127.0.0.1:9200", "http://127.0.0.1:9201"}
config := elasticsearch.Config{
Addresses: addresses,
Username: "",
Password: "",
CloudID: "",
APIKey: "",
}
// new client
es, err := elasticsearch.NewClient(config)
failOnError(err, "Error creating the client")
// Update updates a document with a script or partial document.
var buf bytes.Buffer
doc := map[string]interface{}{
"doc": map[string]interface{}{
"title": "更新你看到外面的世界是什么样的？",
"content": "更新外面的世界真的很精彩",
},
}
if err := json.NewEncoder(&buf).Encode(doc); err != nil {
failOnError(err, "Error encoding doc")
}
res, err := es.Update("demo", "esd", &buf, es.Update.WithDocumentType("doc"))
if err != nil {
failOnError(err, "Error Update response")
}
defer res.Body.Close()
fmt.Println(res.String())
}
UpdateByQuery 通过匹配条件更新文档
func UpdateByQuery() {
addresses := []string{"http://127.0.0.1:9200", "http://127.0.0.1:9201"}
config := elasticsearch.Config{
Addresses: addresses,
Username: "",
Password: "",
CloudID: "",
APIKey: "",
}
// new client
es, err := elasticsearch.NewClient(config)
failOnError(err, "Error creating the client")
// UpdateByQuery performs an update on every document in the index without changing the source,
// for example to pick up a mapping change.
index := []string{"demo"}
var buf bytes.Buffer
doc := map[string]interface{}{
"query": map[string]interface{}{
"match": map[string]interface{}{
"title": "外面",
},
},
// 根据搜索条件更新title
/*
"script": map[string]interface{}{
"source": "ctx._source['title']='更新你看到外面的世界是什么样的？'",
},
*/
// 根据搜索条件更新title、content
/*
"script": map[string]interface{}{
"source": "ctx._source=params",
"params": map[string]interface{}{
"title": "外面的世界真的很精彩",
"content": "你看到外面的世界是什么样的？",
},
"lang": "painless",
},
*/
// 根据搜索条件更新title、content
"script": map[string]interface{}{
"source": "ctx._source.title=params.title;ctx._source.content=params.content;",
"params": map[string]interface{}{
"title": "看看外面的世界真的很精彩",
"content": "他们和你看到外面的世界是什么样的？",
},
"lang": "painless",
},
}
if err := json.NewEncoder(&buf).Encode(doc); err != nil {
failOnError(err, "Error encoding doc")
}
res, err := es.UpdateByQuery(
index,
es.UpdateByQuery.WithDocumentType("doc"),
es.UpdateByQuery.WithBody(&buf),
es.UpdateByQuery.WithContext(context.Background()),
es.UpdateByQuery.WithPretty(),
)
if err != nil {
failOnError(err, "Error Update response")
}
defer res.Body.Close()
fmt.Println(res.String())
}
本文来自：简书
感谢作者：是个懒人
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