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/fetch_source_context.go

@@ -0,0 +1,90 @@
+// 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 (
+	"net/url"
+	"strings"
+)
+
+// FetchSourceContext enables source filtering, i.e. it allows control
+// over how the _source field is returned with every hit. It is used
+// with various endpoints, e.g. when searching for documents, retrieving
+// individual documents, or even updating documents.
+//
+// See https://www.elastic.co/guide/en/elasticsearch/reference/7.0/search-request-source-filtering.html
+// for details.
+type FetchSourceContext struct {
+	fetchSource bool
+	includes    []string
+	excludes    []string
+}
+
+// NewFetchSourceContext returns a new FetchSourceContext.
+func NewFetchSourceContext(fetchSource bool) *FetchSourceContext {
+	return &FetchSourceContext{
+		fetchSource: fetchSource,
+		includes:    make([]string, 0),
+		excludes:    make([]string, 0),
+	}
+}
+
+// FetchSource indicates whether to return the _source.
+func (fsc *FetchSourceContext) FetchSource() bool {
+	return fsc.fetchSource
+}
+
+// SetFetchSource specifies whether to return the _source.
+func (fsc *FetchSourceContext) SetFetchSource(fetchSource bool) {
+	fsc.fetchSource = fetchSource
+}
+
+// Include indicates to return specific parts of the _source.
+// Wildcards are allowed here.
+func (fsc *FetchSourceContext) Include(includes ...string) *FetchSourceContext {
+	fsc.includes = append(fsc.includes, includes...)
+	return fsc
+}
+
+// Exclude indicates to exclude specific parts of the _source.
+// Wildcards are allowed here.
+func (fsc *FetchSourceContext) Exclude(excludes ...string) *FetchSourceContext {
+	fsc.excludes = append(fsc.excludes, excludes...)
+	return fsc
+}
+
+// Source returns the JSON-serializable data to be used in a body.
+func (fsc *FetchSourceContext) Source() (interface{}, error) {
+	if !fsc.fetchSource {
+		return false, nil
+	}
+	if len(fsc.includes) == 0 && len(fsc.excludes) == 0 {
+		return true, nil
+	}
+	src := make(map[string]interface{})
+	if len(fsc.includes) > 0 {
+		src["includes"] = fsc.includes
+	}
+	if len(fsc.excludes) > 0 {
+		src["excludes"] = fsc.excludes
+	}
+	return src, nil
+}
+
+// Query returns the parameters in a form suitable for a URL query string.
+func (fsc *FetchSourceContext) Query() url.Values {
+	params := url.Values{}
+	if fsc.fetchSource {
+		if len(fsc.includes) > 0 {
+			params.Add("_source_includes", strings.Join(fsc.includes, ","))
+		}
+		if len(fsc.excludes) > 0 {
+			params.Add("_source_excludes", strings.Join(fsc.excludes, ","))
+		}
+	} else {
+		params.Add("_source", "false")
+	}
+	return params
+}