fix: sql query with elasticsearch version 6.x (#158)

* fix: sql query with version 6.x

* docs: update release notes

* docs: typo release notes

---------

Co-authored-by: hardy <luohf@infinilabs.com>

docs/content.en/docs/release-notes/_index.md

@@ -18,8 +18,9 @@ Information about release notes of INFINI Console is provided here.
 ### Bug fix
 - Fixed the error when querying empty metric data (#144)
 - Fixed empty host when setup step finishes (#147)
-- Fixed the error of obtaining suggestions of field's value in discover
-- Fixed the wrong display of heatmap's data in alerting message
+- Fixed the error of obtaining suggestions of field's value in discover (#151)
+- Fixed the wrong display of heatmap's data in alerting message (#157)
+- Fixed Devtools `_sql` support for elasticsearch 6.x (#158) 
 
 ### Improvements
 - Update agent config with cluster name (#148)

docs/content.zh/docs/release-notes/_index.md

@@ -18,8 +18,9 @@ title: "版本历史"
 ### Bug fix
 - 修复指标数据为空时的查询错误 (#144)
 - 修复初始化结束步骤中主机显示为错误的问题 (#147)
-- 修复数据探索中获取字段值建议的错误
-- 修复告警消息热图数据显示错误的问题
+- 修复数据探索中获取字段值建议的错误 (#151)
+- 修复告警消息热图数据显示错误的问题 (#157)
+- 修复开发工具 `_sql` 查询支撑 Elasticsearch 6.x 版本 (#158)
 
 ### Improvements
 - 优化下发给 Agent 的配置，增加集群名称 (#148)

modules/elastic/api/proxy.go

@@ -80,6 +80,7 @@ func (h *APIHandler) HandleProxyAction(w http.ResponseWriter, req *http.Request,
 	}
 	if strings.Trim(newURL.Path, "/") == "_sql" {
 		distribution := esClient.GetVersion().Distribution
+		version := esClient.GetVersion().Number
 		indexName, err := rewriteTableNamesOfSqlRequest(req, distribution)
 		if err != nil {
 			h.WriteError(w, err.Error(), http.StatusInternalServerError)
@@ -92,6 +93,15 @@ func (h *APIHandler) HandleProxyAction(w http.ResponseWriter, req *http.Request,
 		q, _ := url.ParseQuery(newURL.RawQuery)
 		hasFormat := q.Has("format")
 		switch distribution {
+		case elastic.Elasticsearch:
+			if !hasFormat {
+				q.Add("format", "txt")
+			}
+			if large, _ := util.VersionCompare(version, "7.0.0"); large > 0 {
+				path = "_sql?" + q.Encode()
+			} else {
+				path = "_xpack/_sql?" + q.Encode()
+			}
 		case elastic.Opensearch:
 			path = "_plugins/_sql?format=raw"
 		case elastic.Easysearch: