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_nested.go

@@ -0,0 +1,96 @@
+// 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
+
+// NestedQuery allows to query nested objects / docs.
+// The query is executed against the nested objects / docs as if they were
+// indexed as separate docs (they are, internally) and resulting in the
+// root parent doc (or parent nested mapping).
+//
+// For more details, see
+// https://www.elastic.co/guide/en/elasticsearch/reference/7.0/query-dsl-nested-query.html
+type NestedQuery struct {
+	query          Query
+	path           string
+	scoreMode      string
+	boost          *float64
+	queryName      string
+	innerHit       *InnerHit
+	ignoreUnmapped *bool
+}
+
+// NewNestedQuery creates and initializes a new NestedQuery.
+func NewNestedQuery(path string, query Query) *NestedQuery {
+	return &NestedQuery{path: path, query: query}
+}
+
+// ScoreMode specifies the score mode.
+func (q *NestedQuery) ScoreMode(scoreMode string) *NestedQuery {
+	q.scoreMode = scoreMode
+	return q
+}
+
+// Boost sets the boost for this query.
+func (q *NestedQuery) Boost(boost float64) *NestedQuery {
+	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 *NestedQuery) QueryName(queryName string) *NestedQuery {
+	q.queryName = queryName
+	return q
+}
+
+// InnerHit sets the inner hit definition in the scope of this nested query
+// and reusing the defined path and query.
+func (q *NestedQuery) InnerHit(innerHit *InnerHit) *NestedQuery {
+	q.innerHit = innerHit
+	return q
+}
+
+// IgnoreUnmapped sets the ignore_unmapped option for the filter that ignores
+// unmapped nested fields
+func (q *NestedQuery) IgnoreUnmapped(value bool) *NestedQuery {
+	q.ignoreUnmapped = &value
+	return q
+}
+
+// Source returns JSON for the query.
+func (q *NestedQuery) Source() (interface{}, error) {
+	query := make(map[string]interface{})
+	nq := make(map[string]interface{})
+	query["nested"] = nq
+
+	src, err := q.query.Source()
+	if err != nil {
+		return nil, err
+	}
+	nq["query"] = src
+
+	nq["path"] = q.path
+
+	if q.scoreMode != "" {
+		nq["score_mode"] = q.scoreMode
+	}
+	if q.boost != nil {
+		nq["boost"] = *q.boost
+	}
+	if q.queryName != "" {
+		nq["_name"] = q.queryName
+	}
+	if q.ignoreUnmapped != nil {
+		nq["ignore_unmapped"] = *q.ignoreUnmapped
+	}
+	if q.innerHit != nil {
+		src, err := q.innerHit.Source()
+		if err != nil {
+			return nil, err
+		}
+		nq["inner_hits"] = src
+	}
+	return query, nil
+}