go-elasticsearch

The official Go client forElasticsearch.

Caveats

We encourage you to try the package in your projects, just keep these caveats in mind, please:

• This is a work in progress. Not all the planned features, standard in official Elasticsearch clients — retries on failures, auto-discovering nodes, ... — are implemented yet.
• There are no guarantees on API stability. Though the public APIs have been designed very carefully, they can change in a backwards-incompatible way depending on further exploration and user feedback.
• The client targets Elasticsearch 7.x. Support for 6.x and 5.x APIs will be added later.

Installation

Install the package withgo get:

go get -u github.com/elastic/go-elasticsearch

Or, add the package to yourgo.mod file:

require github.com/elastic/go-elasticsearch v0.0.0

Or, clone the repository:

git clone https://github.com/elastic/go-elasticsearch.git && cd go-elasticsearch

A complete example:

mkdir my-elasticsearch-app && cd my-elasticsearch-appcat > go.mod <<-END  module my-elasticsearch-app  require github.com/elastic/go-elasticsearch v0.0.0ENDcat > main.go <<-END  package main  import (    "log"    "github.com/elastic/go-elasticsearch"  )  func main() {    es, _ := elasticsearch.NewDefaultClient()    log.Println(es.Info())  }ENDgo run main.go

Usage

Theelasticsearch package ties together two separate packages for calling the Elasticsearch APIs and transferring data over HTTP:esapi andestransport, respectively.

Use theelasticsearch.NewDefaultClient() function to create the client with the default settings.

es, err := elasticsearch.NewDefaultClient()if err != nil {  log.Fatalf("Error creating the client: %s", err)}res, err := es.Info()if err != nil {  log.Fatalf("Error getting response: %s", err)}log.Println(res)// [200 OK] {//   "name" : "node-1",//   "cluster_name" : "go-elasticsearch"// ...

NOTE: When you export theELASTICSEARCH_URL environment variable, it will be used as the cluster endpoint.

To configure the client, use theelasticsearch.NewClient() function (the options are for illustrative purposes only).

cfg := elasticsearch.Config{  Addresses: []string{    "http://localhost:9200",    "http://localhost:9201",  },  Transport: &http.Transport{    MaxIdleConnsPerHost:   10,    ResponseHeaderTimeout: time.Second,    DialContext:           (&net.Dialer{Timeout: time.Second}).DialContext,    TLSClientConfig: &tls.Config{      MaxVersion:         tls.VersionTLS11,      InsecureSkipVerify: true,    },  },}es, err := elasticsearch.NewClient(cfg)// ...

The following example demonstrates a more complex usage. It fetches the Elasticsearch version from the cluster, indexes a couple of documents concurrently, and prints the search results, using a light wrapper around the response body.

// $ go run _examples/main.gopackage mainimport (  "context"  "encoding/json"  "log"  "strconv"  "strings"  "sync"  "github.com/elastic/go-elasticsearch"  "github.com/elastic/go-elasticsearch/esapi")func main() {  log.SetFlags(0)  var (    r  map[string]interface{}    wg sync.WaitGroup  )  // Initialize a client with the default settings.  //  // An `ELASTICSEARCH_URL` environment variable will be used when exported.  //  es, err := elasticsearch.NewDefaultClient()  if err != nil {    log.Fatalf("Error creating the client: %s", err)  }  // 1. Get cluster info  //  res, err := es.Info()  if err != nil {    log.Fatalf("Error getting response: %s", err)  }  // Deserialize the response into a map.  if err := json.NewDecoder(res.Body).Decode(&r); err != nil {    log.Fatalf("Error parsing the response body: %s", err)  }  // Print version number.  log.Printf("~~~~~~~> Elasticsearch %s", r["version"].(map[string]interface{})["number"])  // 2. Index documents concurrently  //  for i, title := range []string{"Test One", "Test Two"} {    wg.Add(1)    go func(i int, title string) {      defer wg.Done()      // Set up the request object directly.      req := esapi.IndexRequest{        Index:      "test",        DocumentID: strconv.Itoa(i + 1),        Body:       strings.NewReader(`{"title" : "` + title + `"}`),        Refresh:    "true",      }      // Perform the request with the client.      res, err := req.Do(context.Background(), es)      if err != nil {        log.Fatalf("Error getting response: %s", err)      }      defer res.Body.Close()      if res.IsError() {        log.Printf("[%s] Error indexing document ID=%d", res.Status(), i+1)      } else {        // Deserialize the response into a map.        var r map[string]interface{}        if err := json.NewDecoder(res.Body).Decode(&r); err != nil {          log.Printf("Error parsing the response body: %s", err)        } else {          // Print the response status and indexed document version.          log.Printf("[%s] %s; version=%d", res.Status(), r["result"], int(r["_version"].(float64)))        }      }    }(i, title)  }  wg.Wait()  log.Println(strings.Repeat("-", 37))  // 3. Search for the indexed documents  //  // Use the helper methods of the client.  res, err = es.Search(    es.Search.WithContext(context.Background()),    es.Search.WithIndex("test"),    es.Search.WithBody(strings.NewReader(`{"query" : { "match" : { "title" : "test" } }}`)),    es.Search.WithTrackTotalHits(true),    es.Search.WithPretty(),  )  if err != nil {    log.Fatalf("ERROR: %s", err)  }  defer res.Body.Close()  if res.IsError() {    var e map[string]interface{}    if err := json.NewDecoder(res.Body).Decode(&e); err != nil {      log.Fatalf("error parsing the response body: %s", err)    } else {      // Print the response status and error information.      log.Fatalf("[%s] %s: %s",        res.Status(),        e["error"].(map[string]interface{})["type"],        e["error"].(map[string]interface{})["reason"],      )    }  }  if err := json.NewDecoder(res.Body).Decode(&r); err != nil {    log.Fatalf("Error parsing the response body: %s", err)  }  // Print the response status, number of results, and request duration.  log.Printf(    "[%s] %d hits; took: %dms",    res.Status(),    int(r["hits"].(map[string]interface{})["total"].(map[string]interface{})["value"].(float64)),    int(r["took"].(float64)),  )  // Print the ID and document source for each hit.  for _, hit := range r["hits"].(map[string]interface{})["hits"].([]interface{}) {    log.Printf(" * ID=%s, %s", hit.(map[string]interface{})["_id"], hit.(map[string]interface{})["_source"])  }  log.Println(strings.Repeat("=", 37))}// ~~~~~~~> Elasticsearch 7.0.0-SNAPSHOT// [200 OK] updated; version=1// [200 OK] updated; version=1// -------------------------------------// [200 OK] 2 hits; took: 7ms//  * ID=1, map[title:Test One]//  * ID=2, map[title:Test Two]// =====================================

As you see in the example above, theesapi package allows to call the Elasticsearch APIs in two distinct ways: either by creating a struct, such asIndexRequest, and calling itsDo() method by passing it a context and the client, or by calling theSearch() function on the client directly, using the option functions such asWithIndex(). See more information and examples in the package documentation.

Theestransport package handles the transfer of data to and from Elasticsearch. At the moment, the implementation is really minimal: it only round-robins across the configured cluster endpoints. In future, more features — retrying failed requests, ignoring certain status codes, auto-discovering nodes in the cluster, and so on — will be added.

Examples

The_examples folder contains a number of recipes and comprehensive examples to get you started with the client, including configuration and customization of the client, mocking the transport for unit tests, embedding the client in a custom type, building queries, performing requests, and parsing the responses.

License

(c) 2019 Elasticsearch. Licensed under the Apache License, Version 2.0.

elasticsearch.NewDefaultClient()

cfg := elasticsearch.Config{  Addresses: []string{    "http://localhost:9200",    "http://localhost:9201",  },  Transport: &http.Transport{    MaxIdleConnsPerHost:   10,    ResponseHeaderTimeout: time.Second,    DialContext:           (&net.Dialer{Timeout: time.Second}).DialContext,    TLSClientConfig: &tls.Config{      MaxVersion:         tls.VersionTLS11,      InsecureSkipVerify: true,    },  },}elasticsearch.NewClient(cfg)

res, err := es.Info()if err != nil {  log.Fatalf("Error getting response: %s", err)}log.Println(res)

Constants¶

Variables¶

Functions¶

Types¶

type Client struct {*esapi.API// Embeds the API methodsTransportestransport.Interface}

func NewClient(cfgConfig) (*Client,error)

cfg := elasticsearch.Config{Addresses: []string{"http://localhost:9200",},Transport: &http.Transport{MaxIdleConnsPerHost:   10,ResponseHeaderTimeout: time.Second,DialContext:           (&net.Dialer{Timeout: time.Second}).DialContext,TLSClientConfig: &tls.Config{MaxVersion:         tls.VersionTLS11,InsecureSkipVerify: true,},},}es, _ := elasticsearch.NewClient(cfg)log.Print(es.Transport.(*estransport.Client).URLs())

func NewDefaultClient() (*Client,error)

es, err := elasticsearch.NewDefaultClient()if err != nil {log.Fatalf("Error creating the client: %s\n", err)}res, err := es.Info()if err != nil {log.Fatalf("Error getting the response: %s\n", err)}defer res.Body.Close()log.Print(es.Transport.(*estransport.Client).URLs())

func (c *Client) Perform(req *http.Request) (*http.Response,error)

type Config struct {Addresses []string// A list of Elasticsearch nodes to use.Transporthttp.RoundTripper// The HTTP transport object.}