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/search_queries_terms.go

@@ -0,0 +1,75 @@
+// 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
+
+// TermsQuery filters documents that have fields that match any
+// of the provided terms (not analyzed).
+//
+// For more details, see
+// https://www.elastic.co/guide/en/elasticsearch/reference/7.0/query-dsl-terms-query.html
+type TermsQuery struct {
+	name        string
+	values      []interface{}
+	termsLookup *TermsLookup
+	queryName   string
+	boost       *float64
+}
+
+// NewTermsQuery creates and initializes a new TermsQuery.
+func NewTermsQuery(name string, values ...interface{}) *TermsQuery {
+	q := &TermsQuery{
+		name:   name,
+		values: make([]interface{}, 0),
+	}
+	if len(values) > 0 {
+		q.values = append(q.values, values...)
+	}
+	return q
+}
+
+// TermsLookup adds terms lookup details to the query.
+func (q *TermsQuery) TermsLookup(lookup *TermsLookup) *TermsQuery {
+	q.termsLookup = lookup
+	return q
+}
+
+// Boost sets the boost for this query.
+func (q *TermsQuery) Boost(boost float64) *TermsQuery {
+	q.boost = &boost
+	return q
+}
+
+// QueryName sets the query name for the filter that can be used
+// when searching for matched_filters per hit
+func (q *TermsQuery) QueryName(queryName string) *TermsQuery {
+	q.queryName = queryName
+	return q
+}
+
+// Creates the query source for the term query.
+func (q *TermsQuery) Source() (interface{}, error) {
+	// {"terms":{"name":["value1","value2"]}}
+	source := make(map[string]interface{})
+	params := make(map[string]interface{})
+	source["terms"] = params
+
+	if q.termsLookup != nil {
+		src, err := q.termsLookup.Source()
+		if err != nil {
+			return nil, err
+		}
+		params[q.name] = src
+	} else {
+		params[q.name] = q.values
+		if q.boost != nil {
+			params["boost"] = *q.boost
+		}
+		if q.queryName != "" {
+			params["_name"] = q.queryName
+		}
+	}
+
+	return source, nil
+}