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golang操作ES
本文主要是简单介绍 golang调用ES的增删改查方法，具体文档详见：github.com/olivere/ela…
连接ES
esClient, err = elastic.NewClient(elastic.SetURL(host_address), elastic.SetSniff(false))
创建索引Index
ES的Index就是数据库的表,按天创建索引, 映射（mapping） 映射是定义一个文档以及其所包含的字段如何被存储和索引的方法。
#定义index的索引接口
var mapping = `{
"settings":{
"number_of_shards":1,
"number_of_replicas":0
},
"properties":{
"@timestamp":{
"format":"strict_date_optional_time||epoch_millis",
"type":"date",
"enabled":true
}
}
}`
var DATESET sync.Map
具体参考ES Mapping详解
func createIndex(index string) string {
t := time.Now()
date := t.Format("20060102")
findex := index + date
_, ok := DATESET.Load(findex)
if !ok {
exists, err := esClient.IndexExists(findex).Do(context.Background())
if err != nil {
panic(err)
}
if !exists {
esClient.CreateIndex(findex).BodyString(mapping).Do(context.Background())
}
DATESET.Store(findex, date)
}
return findex
}
删除索引
func deleteIndex(indexName string) error {
var err error
ctx := context.Background()
exists, err := esClient.IndexExists(indexName).Do(ctx)
if err != nil {
log.Println("IndexExists" + err.Error())
return err
}
if exists {
deleteIndex, err := esClient.DeleteIndex(indexName).Do(ctx)
fmt.Println("DeleteIndex[", indexName, "]=>", err, "res=", deleteIndex)
if err != nil {
// Handle error
return err
}
if !deleteIndex.Acknowledged {
// Not acknowledged
return errors.New("delete index is not Acknowledged")
}
}
return err
}
写入数据
tweet1 := tweet{User: "olivere", Message: "Welcome to Golang and Elasticsearch."}
tweet2 := tweet{User: "olivere", Message: "Another unrelated topic."}
tweet3 := tweet{User: "sandrae", Message: "Cycling is fun."}
// Add all documents 需要制定IndexName，和ID，删除数据的时候可以根据ID单条删除数据
_, err := client.Index().Index(IndexName).Id("1").BodyJson(&tweet1).Do(context.TODO())
if err != nil {
t.Fatal(err)
}
_, err = client.Refresh().Index(IndexName).Do(context.TODO())
if err != nil {
t.Fatal(err)
}
// Count documents 统计Index下的数据量
count, err := client.Count(IndexName).Do(context.TODO())
if err != nil {
t.Fatal(err)
}
查询数据
- 根据ID查询
// Get document 1 根据INDEX和ID查询
res, err := client.Get().Index(IndexName).Id("1").Do(context.TODO())
if err != nil {
t.Fatal(err)
}
if res.Found != true {
t.Errorf("expected Found = true; got %v", res.Found)
}
if res.Source == nil {
t.Errorf("expected Source != nil; got %v", res.Source)
}
- 根据字段查询
#mapping 定义
testMapping = `
{
"settings":{
"number_of_shards":1,
"number_of_replicas":0
},
"mappings":{
"properties":{
"user":{
"type":"keyword"
},
"message":{
"type":"text",
"store": true,
"fielddata": true
},
"tags":{
"type":"keyword"
},
"location":{
"type":"geo_point"
},
"suggest_field":{
"type":"completion"
}
}
}
}
`
#创建索引
createIndex, err := client.CreateIndex(testIndexName).Body(testMapping).Do(context.TODO())
if err != nil {
t.Fatal(err)
}
if createIndex == nil {
t.Errorf("expected result to be != nil; got: %v", createIndex)
}
# 准备数据
tweet1 := tweet{
User: "olivere",
Retweets: 108,
Message: "Welcome to Golang and Elasticsearch.",
Image: "http://golang.org/doc/gopher/gophercolor.png",
Tags: []string{"golang", "elasticsearch"},
Location: "48.1333,11.5667", // lat,lon
Created: time.Date(2012, 12, 12, 17, 38, 34, 0, time.UTC),
}
tweet2 := tweet{
User: "olivere",
Retweets: 0,
Message: "Another unrelated topic.",
Tags: []string{"golang"},
Location: "48.1189,11.4289", // lat,lon
Created: time.Date(2012, 10, 10, 8, 12, 03, 0, time.UTC),
}
tweet3 := tweet{
User: "sandrae",
Retweets: 12,
Message: "Cycling is fun.",
Tags: []string{"sports", "cycling"},
Location: "47.7167,11.7167", // lat,lon
Created: time.Date(2011, 11, 11, 10, 58, 12, 0, time.UTC),
}
# 插入数据
_, err := client.Index().Index(testIndexName).Id("1").BodyJson(&tweet1).Do(context.TODO())
if err != nil {
t.Fatal(err)
}
_, err = client.Index().Index(testIndexName).Id("2").BodyJson(&tweet2).Do(context.TODO())
if err != nil {
t.Fatal(err)
}
_, err = client.Index().Index(testIndexName).Id("3").BodyJson(&tweet3).Do(context.TODO())
if err != nil {
t.Fatal(err)
}
# 查询全量数据
all := NewMatchAllQuery()
searchResult, err := client.Search().
Index(testIndexName).
Query(all).
Size(100). //limit返回结果集
Sort("created", false). //按时间排序
Pretty(true).
Do(context.TODO())
# 根据条件查询
{
"query": {
"match": {"message": "吃饭睡觉"} //模糊查询 匹配字段message中跟”吃饭睡觉“相关的所有数据，比如”吃饭xxxx“、”睡觉xxxxx“、”吃xxxx“........;
}
}
{
"query": {
"match_phrase": {"message": "吃饭睡觉"} //精确查询 确匹配出message等于”吃饭睡觉“的所有数据
}
}
{
"query": {
"multi_match": {
"query": "小陈",
"fields": ["user", "message"] //多字段模糊查询
}
}
}
searchResult, err := client.Search().
Index(testIndexName).
Source(`{"query":{"match_all":{}}}`). // sets the JSON request
Do(context.TODO())
# 查询特定字段
searchResult, err := client.Search().
Index(testIndexName).
Source(`{"query":{"match_all":{}}}`). // sets the JSON request
StoredFields("message").
DocvalueFields("retweets").
Sort("created", true).
Do(context.TODO())
#结果集合在searchResult.Hits.Hits.Fileds中
ES的查询博大精深，本篇文章属于基础入门，内容来源于官网
