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gin 和 go-elasticsearch 如何结合使用？

来源：stackoverflow 2024-02-15 21:27:22 0浏览收藏

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问题内容

使用 gin 作为 api。

它的route.go

func init(api *gin.engine) {
    r := api.group("/v1")
    r.get("/sites/search/:url", site.search)
}

在控制器文件中，想要使用go-elasticsearch搜索es数据。

import (
    "context"
    "github.com/myapp/common/elasticsearch"
)

func search(ctx *gin.context) {
   var data bool
   data = getes(ctx.request.context()) 
}

func getes(ctx context.context) bool {
    var (
        r   map[string]interface{}
        buf bytes.buffer
    )

    var buf bytes.buffer
    query := map[string]interface{}{
        "query": map[string]interface{}{
            "match": map[string]interface{}{
                "title": "test",
            },
        },
    }
    if err := json.newencoder(&buf).encode(query); err != nil {
        log.fatalf("error encoding query: %s", err)
    }


    res, err := elasticsearch.esclient.search(
        elasticsearch.esclient.search.withcontext(ctx),
        elasticsearch.esclient.search.withindex("indexname"),
        elasticsearch.esclient.search.withbody(&buf),
        elasticsearch.esclient.search.withtracktotalhits(true),
    )
    // ...
}

当前go-elasticsearch的初始化方法正在使用公共文件中的ctx context.context：

import (
    "context"
    elasticsearch "github.com/elastic/go-elasticsearch/v8"
    "github.com/elastic/go-elasticsearch/v8/esapi"
)

func init(ctx context.context) {
    var (
        esclient = *elasticsearch.client
    )
    // ...
    res, err := esapi.inforequest{}.do(ctx, esclient)
    // ...
}

如果在控制器search函数中使用req *http.request，则可以成功调用数据。但是gin的ctx *gin.context会导致错误：

runtime error: invalid memory address or nil pointer dereference
/usr/local/go/src/runtime/panic.go:199 (0x44470b)
    panicmem: panic(memoryerror)
/usr/local/go/src/runtime/signal_unix.go:394 (0x444548)
    sigpanic: panicmem()
/application/site/controller.go:100 (0xe9afea)
    getes: elasticsearch.esclient.search.withcontext(ctx),
/application/site/controller.go:77 (0xe9a8a4)
    search: data = getes(ctx.request.context())
/go/pkg/mod/github.com/gin-gonic/[email protected]/context.go:161 (0x987fda)
    (*context).next: c.handlers[c.index](c)
/app/service/console/application/golang/console-api/application/auth/authenticate.go:16 (0xb90f7a)
    apikeyauthenticate.func1: ctx.next()
/go/pkg/mod/github.com/gin-gonic/[email protected]/context.go:161 (0x987fda)
    (*context).next: c.handlers[c.index](c)
/app/service/console/application/golang/console-api/application/error/error_handler.go:13 (0xb3c60e)
    handle500.func1: ctx.next()
/go/pkg/mod/github.com/gin-gonic/[email protected]/context.go:161 (0x987fda)
    (*context).next: c.handlers[c.index](c)
/app/service/console/application/golang/console-api/application/error/error_handler.go:27 (0xb3c84f)
    handle400.func1: ctx.next()
/go/pkg/mod/github.com/gin-gonic/[email protected]/context.go:161 (0x987fda)
    (*context).next: c.handlers[c.index](c)
/go/pkg/mod/github.com/gin-gonic/[email protected]/recovery.go:83 (0x99bad3)
    recoverywithwriter.func1: c.next()
/go/pkg/mod/github.com/gin-gonic/[email protected]/context.go:161 (0x987fda)
    (*context).next: c.handlers[c.index](c)
/go/pkg/mod/github.com/gin-gonic/[email protected]/logger.go:241 (0x99ac00)
    loggerwithconfig.func1: c.next()
/go/pkg/mod/github.com/gin-gonic/[email protected]/context.go:161 (0x987fda)
    (*context).next: c.handlers[c.index](c)
/go/pkg/mod/github.com/gin-gonic/[email protected]/gin.go:409 (0x991f1c)
    (*engine).handlehttprequest: c.next()
/go/pkg/mod/github.com/gin-gonic/[email protected]/gin.go:367 (0x99161d)
    (*engine).servehttp: engine.handlehttprequest(c)
/usr/local/go/src/net/http/server.go:2802 (0x6dc303)
    serverhandler.servehttp: handler.servehttp(rw, req)
/usr/local/go/src/net/http/server.go:1890 (0x6d7ba4)
    (*conn).serve: serverhandler{c.server}.servehttp(w, w.req)
/usr/local/go/src/runtime/asm_amd64.s:1357 (0x45d300)
    goexit: byte    $0x90   // nop

我还尝试在 getes 函数中使用 ctx *gin.context

func getes(ctx *gin.context) bool {

或者在es的搜索方法中设置context.background()：

elasticsearch.ESClient.Search.WithContext(context.Background()),

仍然有错误。

如何将 gin 与 go-elasticsearch 以及合适的 context 类型一起使用？

这个方法需要什么内容？

https://github.com/elastic/go-elasticsearch/blob/master/_examples/main.go#l127

解决方案

*gin.context 与 go-elasticsearch 询问的上下文不同，如果您在 *gin.context 中有搜索词，您可以使用 search() 等函数获取并查询它们。

package main
    
    import (
        "bytes"
        "context"
        "encoding/json"
        es "github.com/elastic/go-elasticsearch"
        api "github.com/elastic/go-elasticsearch/esapi"
        app "github.com/gin-gonic/gin"
        "io/ioutil"
        "log"
        "net/http"
        "strings"
    )
    
    var c *es.Client
    
    func init() {
        // connect to elastic search client
        cf := es.Config{
            Addresses: []string{
                "http://localhost:9200",
            },
        }
        e, err := es.NewClient(cf)
        if err != nil {
            log.Println(err)
        }
        c = e
        // make a new index
        // put some new data
        // search database for data
    }
    
    
    
    func search(term string, key string) (by []byte, err error) {
        q := map[string]interface{}{
            "query": map[string]interface{}{
                "match": map[string]interface{}{
                    key: term},
            },
        }
        var bts bytes.Buffer
        if err = json.NewEncoder(&bts).Encode(q); err != nil {
            return
        }
        r, err := c.Search(
            c.Search.WithContext(context.Background()),
            c.Search.WithIndex("test"),
            c.Search.WithBody(&bts),
            c.Search.WithTrackTotalHits(true),
            c.Search.WithPretty(),
        )
        if err != nil {
            return
        }
        defer r.Body.Close()
        by, err = ioutil.ReadAll(r.Body)
        if err != nil || r.StatusCode != http.StatusOK {
            return
        }
        return
    }
    
    func handlerr(a interface{}, err error) {
        if err != nil {
            log.Println(err)
        }
        log.Printf("%s", a)
    }
    func main() {
        r:=app.Default()
        r.GET("/",GetES)
        r.Run(":8080")
        return
    }
      
    
     func GetES(c *gin.Context){
       res, err := search("my experiments with truth", "title")
       handlerr(res,err)
       c.JSON{http.StatusOK,res}
       return
     }

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