Issue search support elasticsearch (#9428)

* Issue search support elasticsearch

* Fix lint

* Add indexer name on app.ini

* add a warnning on SearchIssuesByKeyword

* improve code

vendor/github.com/olivere/elastic/v7/response.go

@@ -0,0 +1,62 @@
+// Copyright 2012-present Oliver Eilhard. All rights reserved.
+// Use of this source code is governed by a MIT-license.
+// See http://olivere.mit-license.org/license.txt for details.
+
+package elastic
+
+import (
+	"encoding/json"
+	"errors"
+	"io"
+	"io/ioutil"
+	"net/http"
+)
+
+var (
+	// ErrResponseSize is raised if a response body exceeds the given max body size.
+	ErrResponseSize = errors.New("elastic: response size too large")
+)
+
+// Response represents a response from Elasticsearch.
+type Response struct {
+	// StatusCode is the HTTP status code, e.g. 200.
+	StatusCode int
+	// Header is the HTTP header from the HTTP response.
+	// Keys in the map are canonicalized (see http.CanonicalHeaderKey).
+	Header http.Header
+	// Body is the deserialized response body.
+	Body json.RawMessage
+	// DeprecationWarnings lists all deprecation warnings returned from
+	// Elasticsearch.
+	DeprecationWarnings []string
+}
+
+// newResponse creates a new response from the HTTP response.
+func (c *Client) newResponse(res *http.Response, maxBodySize int64) (*Response, error) {
+	r := &Response{
+		StatusCode:          res.StatusCode,
+		Header:              res.Header,
+		DeprecationWarnings: res.Header["Warning"],
+	}
+	if res.Body != nil {
+		body := io.Reader(res.Body)
+		if maxBodySize > 0 {
+			if res.ContentLength > maxBodySize {
+				return nil, ErrResponseSize
+			}
+			body = io.LimitReader(body, maxBodySize+1)
+		}
+		slurp, err := ioutil.ReadAll(body)
+		if err != nil {
+			return nil, err
+		}
+		if maxBodySize > 0 && int64(len(slurp)) > maxBodySize {
+			return nil, ErrResponseSize
+		}
+		// HEAD requests return a body but no content
+		if len(slurp) > 0 {
+			r.Body = json.RawMessage(slurp)
+		}
+	}
+	return r, nil
+}