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This article mainly introduces the relevant knowledge of "the method of operating es with go language". The editor shows you the operation process through the actual case. The operation method is simple, fast and practical. I hope this article "the method of operating es with go language" can help you solve the problem.

Elasticsearch introduction

Elasticsearch (ES) is an open source, distributed, RESTful interface full-text search engine based on Lucene. Elasticsearch is also a distributed document database, in which each field can be indexed and the data of each field can be searched, and ES can scale out to hundreds of servers to store and process PB-level data. A large amount of data can be stored, searched, and analyzed in a very short time. It is usually used as the core engine with complex search scenarios.

What can Elasticsearch do?

When you run an online store, you can ask your customers to search for the products you sell. In this case, you can use ElasticSearch to store your entire product catalog and inventory information, provide customers with accurate search, and recommend related products to customers.

When you want to collect log or transaction data, you need to analyze and mine the data, look for trends, count, summarize, or find anomalies. In this case, you can use Logstash or other tools to collect data when this causes the data to be stored in ElasticsSearch. You can search and aggregate this data and find any information you are interested in.

A well-known case for programmers is that GitHub,GitHub 's search is based on ElasticSearch, where you can search for projects, users, issue, pull request, and code on the github.com/search page. There are 40-50 index libraries, which are used to index all kinds of data that the website needs to track. Although only the main branch of the project (master) is indexed, the amount of data is still huge, including 2 billion index documents and 30TB index files.

Go language operates esgo get github.com/olivere/elastic to solve the problem of automatically translating connection addresses when golang uses elastic to connect elasticsearch

Elastic.SetSniff (false) client, _: = elastic.NewClient (/ /... / / when sniff is set to false, the address elastic.SetSniff (false) is not automatically translated.)

Initialize var client * elastic.Clientvar host = "http://xxx:9200"// initialize es driver func init () {errorlog: = log.New (os.Stdout," app ", log.LstdFlags) var err error client, err = elastic.NewClient (elastic.SetErrorLog (errorlog), elastic.SetURL (host), elastic.SetSniff (false) if err! = nil {panic (err)} info, code Err: = client.Ping (host) .Do (context.Background ()) if err! = nil {panic (err)} fmt.Printf ("Es return with code% d and version% s\ n", code, info.Version.Number) esversionCode, err: = client.ElasticsearchVersion (host) if err! = nil {panic (err)} fmt.Printf ("esversion% s\ n", esversionCode)} data creation

Info-> employee-FirstName,LastName,Age,About,Interests

Structural mode

Type Employee struct {FirstName string `json: "firstname" `LastName string `json: "lastname" `Age int `json: "age" `About string `json: "about" `Interests [] string `json: "interests" `} / / create an index func create () {/ / 1. Use structure to store in es E1: = Employee {"jane", "Smith", 20, "I like music", [] string {"music"}} put Err: = client.Index (). Index ("info"). Type ("employee"). Id ("1") .BodyJson (E1) .Do (context.Background ()) if err! = nil {panic (err)} fmt.Printf ("indexed% d to index% s, type% s\ n", put.Id, put.Index, put.Type)} func main () {create ()}

String mode:

Func create1 () {/ / use the string E1: = `{"firstname": "john", "lastname": "smith", "age": 22, "about": "i like book", "interests": ["book", "music"]} `put Err: = client.Index (). Index ("info"). Type ("employee"). Id ("2") .BodyJson (E1) .Do (context.Background ()) if err! = nil {panic (err)} fmt.Printf ("indexed% d to index% s, type% s\ n", put.Id, put.Index, put.Type)} find / / find func get () {get Err: = client.Get (). Index ("info"). Type ("employee"). Id ("1") .Do (context.Background ()) if err! = nil {panic (err)} if get.Found {fmt.Printf ("got document% s in version% d from index% s% s\ n", get.Id, get.Version, get.Index, get.Type)} func main () {get ()} modify func update () {res Err: = client.Update (). Index ("info"). Type ("employee"). Id ("1") .Doc (map [string] interface {} {"age": 88}) .Do (context.Background ()) if err! = nil {fmt.Println (err.Error ())} fmt.Printf ("update age% s\ n", res.Result)} func main () {update ()} delete / / delete func delete () {res () Err: = client.Delete (). Index ("info"). Type ("employee"). Id ("1") .Do (context.Background ()) if err! = nil {fmt.Println (err.Error ())} fmt.Printf ("delete result% s", res.Result)} func main () {delete ()} find func query () {var res * elastic.SearchResult var err error res Err = client.Search ("info"). Type ("employee") .Do (context.Background ()) printEmployee (res, err)} / / print employeefunc printEmployee (res * elastic.SearchResult, err error) {if err! = nil {fmt.Print (err.Error () return} var typ Employee for _, item: = range res.Each (reflect.TypeOf (typ)) {t: = item. (Employee) fmt.Printf ("% # v\ n") T)}} / / conditional search func query1 () {var res * elastic.SearchResult var err error / / search method 1: Q: = elastic.NewQueryStringQuery ("lastname:smith") res, err = client.Search ("info"). Type ("employee") .query (Q) .Do (context.Background ()) printEmployee (res, err) / / search method 2: if res.Hits.TotalHits > 0 {fmt.Printf ("found a total fo% d Employee") Res.Hits.TotalHits) for _, hit: = range res.Hits.Hits {var t Employee err: = json.Unmarshal (* hit.Source, & t) / / another way to take it out if err! = nil {fmt.Println ("failed")} fmt.Printf ("employee name% s\ n", t.FirstName T.LastName)}} else {fmt.Printf ("found no employee\ n")}}

Search for people older than 21

/ func query3 () {var res * elastic.SearchResult var err error boolq: = elastic.NewBoolQuery () boolq.Must (elastic.NewMatchQuery ("lastname", "smith")) boolq.Filter (elastic.NewRangeQuery ("age"). Gt (21) res, err = client.Search ("info"). Type ("employee") .Query (boolq) .Do (context.Background ()) printEmployee (res) Err)} / / print employeefunc printEmployee (res * elastic.SearchResult, err error) {if err! = nil {fmt.Print (err.Error ()) return} var typ Employee for _, item: = range res.Each (reflect.TypeOf (typ)) {t: = item. (Employee) fmt.Printf ("% # v\ n", t)}}

Containing the book

/ / func query4 () {var res * elastic.SearchResult var err error matchPhrase: = elastic.NewMatchPhraseQuery ("about", "book") res, err = client.Search ("info"). Type ("employee") .query (matchPhrase) .Do (context.Background ()) printEmployee (res, err)}

Pagination

/ / paging func list (size, page int) {var res * elastic.SearchResult var err error if size < 0 | | page < 1 {fmt.Printf ("param error") return} res, err = client.Search ("info"). Type ("employee") .size (size). From ((page-1) * size) .Do (context.Background ()) printEmployee (res, err)} Cluster Construction

Profile modification

Node.name: node-102node.name: node-103network.host: 192.168.1.102network.host: 192.168.1.103discovery.zen.ping.unicast.hosts: ["s201", "s202", "S203"]

This is the end of the introduction of "the method of operating es with go language". Thank you for your reading. If you want to know more about the industry, you can follow the industry information channel. The editor will update different knowledge points for you every day.

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