Elasticsearch的官方Go客户-Golang开发

# go-elasticsearch The official Go client for [Elasticsearch](https://www.elastic.co/products/elasticsearch). [](https://pkg.go.dev/github.com/elastic/go-elasticsearch/v8) [](https://goreportcard.com/report/github.com/elastic/go-elasticsearch) [](https://codecov.io/gh/elastic/go-elasticsearch?branch=master) [](https://github.com/elastic/go-elasticsearch/actions?query=branch%3Amaster) [](https://github.com/elastic/go-elasticsearch/actions?query=branch%3Amaster) [](https://github.com/elastic/go-elasticsearch/actions?query=branch%3Amaster) [](https://github.com/elastic/go-elasticsearch/actions?query=branch%3Amaster) ## Compatibility The client major versions correspond to the compatible Elasticsearch major versions: to connect to Elasticsearch `7.x`, use a [`7.x`](https://github.com/elastic/go-elasticsearch/tree/7.x) version of the client, to connect to Elasticsearch `6.x`, use a [`6.x`](https://github.com/elastic/go-elasticsearch/tree/6.x) version of the client. When using Go modules, include the version in the import path, and specify either an explicit version or a branch: require github.com/elastic/go-elasticsearch/v7 7.x require github.com/elastic/go-elasticsearch/v7 7.0.0 It's possible to use multiple versions of the client in a single project: // go.mod github.com/elastic/go-elasticsearch/v6 6.x github.com/elastic/go-elasticsearch/v7 7.x // main.go import ( elasticsearch6 "github.com/elastic/go-elasticsearch/v6" elasticsearch7 "github.com/elastic/go-elasticsearch/v7" ) // ... es6, _ := elasticsearch6.NewDefaultClient() es7, _ := elasticsearch7.NewDefaultClient() The `master` branch of the client is compatible with the current `master` branch of Elasticsearch. <!-- ----------------------------------------------------------------------------------------------- --> ## Installation Add the package to your `go.mod` file: require github.com/elastic/go-elasticsearch/v8 master Or, clone the repository: git clone --branch master https://github.com/elastic/go-elasticsearch.git $GOPATH/src/github.com/elastic/go-elasticsearch A complete example: ```bash mkdir my-elasticsearch-app && cd my-elasticsearch-app cat > go.mod <<-END module my-elasticsearch-app require github.com/elastic/go-elasticsearch/v8 master END cat > main.go <<-END package main import ( "log" "github.com/elastic/go-elasticsearch/v8" ) func main() { es, _ := elasticsearch.NewDefaultClient() log.Println(elasticsearch.Version) log.Println(es.Info()) } END go run main.go ``` <!-- ----------------------------------------------------------------------------------------------- --> ## Usage The `elasticsearch` package ties together two separate packages for calling the Elasticsearch APIs and transferring data over HTTP: `esapi` and `estransport`, respectively. Use the `elasticsearch.NewDefaultClient()` function to create the client with the default settings. ```golang 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) } defer res.Body.Close() log.Println(res) // [200 OK] { // "name" : "node-1", // "cluster_name" : "go-elasticsearch" // ... ``` > NOTE: It is _critical_ to both close the response body _and_ to consume it, in order to re-use persistent TCP connections in the default HTTP transport. If you're not interested in the response body, call `io.Copy(ioutil.Discard, res.Body)`. When you export the `ELASTICSEARCH_URL` environment variable, it will be used to set the cluster endpoint(s). Separate multiple adresses by a comma. To set the cluster endpoint(s) programatically, pass a configuration object to the `elasticsearch.NewClient()` function. ```golang cfg := elasticsearch.Config{ Addresses: []string{ "http://localhost:9200", "http://localhost:9201", }, // ... } es, err := elasticsearch.NewClient(cfg) ``` To set the username and password, include them in the endpoint URL, or use the corresponding configuration options. ```golang cfg := elasticsearch.Config{ // ... Username: "foo", Password: "bar", } ``` To set a custom certificate authority used to sign the certificates of cluster nodes, use the `CACert` configuration option. ```golang cert, _ := ioutil.ReadFile(*cacert) cfg := elasticsearch.Config{ // ... CACert: cert, } ``` To configure other HTTP settings, pass an [`http.Transport`](https://golang.org/pkg/net/http/#Transport) object in the configuration object. ```golang cfg := elasticsearch.Config{ Transport: &http.Transport{ MaxIdleConnsPerHost: 10, ResponseHeaderTimeout: time.Second, TLSClientConfig: &tls.Config{ MinVersion: tls.VersionTLS11, // ... }, // ... }, } ``` See the [`_examples/configuration.go`](_examples/configuration.go) and [`_examples/customization.go`](_examples/customization.go) files for more examples of configuration and customization of the client. See the [`_examples/security`](_examples/security) for an example of a security configuration. 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 lightweight wrapper around the response body. ```golang // $ go run _examples/main.go package main import ( "bytes" "context" "encoding/json" "log" "strconv" "strings" "sync" "github.com/elastic/go-elasticsearch/v8" "github.com/elastic/go-elasticsearch/v8/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) } defer res.Body.Close() // Check response status if res.IsError() { log.Fatalf("Error: %s", res.String()) } // 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 client and server version numbers. log.Printf("Client: %s", elasticsearch.Version) log.Printf("Server: %s", r["version"].(map[string]interface{})["number"]) log.Println(strings.Repeat("~", 37)) // 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() // Build the request body. var b strings.Builder b.WriteString(`{"title" : "`) b.WriteString(title) b.WriteString(`"}`) // Set up the request object. req := esapi.IndexRequest{ Index: "test", DocumentID: strconv.Itoa(i + 1), Body: strings.NewReader(b.String()), 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() {