From a2f7e208fd9e6b56e11aed3a9bdd20b9c6d626a0 Mon Sep 17 00:00:00 2001
From: Ivana Huckova <30407135+ivanahuckova@users.noreply.github.com>
Date: Wed, 5 Jun 2024 15:54:04 +0200
Subject: [PATCH] Elasticsearchl: In version check, include `/` (#88779)

Elasticsearchl: In version check, include /
---
 pkg/tsdb/elasticsearch/elasticsearch.go      | 17 ++++++++++++-----
 pkg/tsdb/elasticsearch/elasticsearch_test.go |  6 +++++-
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/pkg/tsdb/elasticsearch/elasticsearch.go b/pkg/tsdb/elasticsearch/elasticsearch.go
index 69c7fc30a62..354b508463c 100644
--- a/pkg/tsdb/elasticsearch/elasticsearch.go
+++ b/pkg/tsdb/elasticsearch/elasticsearch.go
@@ -218,9 +218,9 @@ func (s *Service) CallResource(ctx context.Context, req *backend.CallResourceReq
 		logger.Error("Failed to create request url", "error", err, "url", ds.URL, "path", req.Path)
 	}
 
-	request, err := http.NewRequestWithContext(ctx, req.Method, esUrl.String(), bytes.NewBuffer(req.Body))
+	request, err := http.NewRequestWithContext(ctx, req.Method, esUrl, bytes.NewBuffer(req.Body))
 	if err != nil {
-		logger.Error("Failed to create request", "error", err, "url", esUrl.String())
+		logger.Error("Failed to create request", "error", err, "url", esUrl)
 		return err
 	}
 
@@ -272,12 +272,19 @@ func (s *Service) CallResource(ctx context.Context, req *backend.CallResourceReq
 	})
 }
 
-func createElasticsearchURL(req *backend.CallResourceRequest, ds *es.DatasourceInfo) (*url.URL, error) {
+func createElasticsearchURL(req *backend.CallResourceRequest, ds *es.DatasourceInfo) (string, error) {
 	esUrl, err := url.Parse(ds.URL)
 	if err != nil {
-		return nil, fmt.Errorf("failed to parse data source URL: %s, error: %w", ds.URL, err)
+		return "", fmt.Errorf("failed to parse data source URL: %s, error: %w", ds.URL, err)
 	}
 
 	esUrl.Path = path.Join(esUrl.Path, req.Path)
-	return esUrl, nil
+	esUrlString := esUrl.String()
+	// If the request path is empty and the URL does not end with a slash, add a slash to the URL.
+	// This ensures that for version checks executed to the root URL, the URL ends with a slash.
+	// This is helpful, for example, for load balancers that expect URLs to match the pattern /.*.
+	if req.Path == "" && esUrlString[len(esUrlString)-1:] != "/" {
+		return esUrl.String() + "/", nil
+	}
+	return esUrlString, nil
 }
diff --git a/pkg/tsdb/elasticsearch/elasticsearch_test.go b/pkg/tsdb/elasticsearch/elasticsearch_test.go
index 798e54bf6d0..93a50bf69e8 100644
--- a/pkg/tsdb/elasticsearch/elasticsearch_test.go
+++ b/pkg/tsdb/elasticsearch/elasticsearch_test.go
@@ -211,13 +211,17 @@ func TestCreateElasticsearchURL(t *testing.T) {
 		{name: "with /abc/_mapping path and valid url", settings: es.DatasourceInfo{URL: "http://localhost:9200/"}, req: backend.CallResourceRequest{Path: "abc/_mapping"}, expected: "http://localhost:9200/abc/_mapping"},
 		// This is to support mappings to cross cluster search that includes ":"
 		{name: "with path including :", settings: es.DatasourceInfo{URL: "http://localhost:9200/"}, req: backend.CallResourceRequest{Path: "ab:c/_mapping"}, expected: "http://localhost:9200/ab:c/_mapping"},
+		{name: "with \"\" path and valid url and /", settings: es.DatasourceInfo{URL: "http://localhost:9200/"}, req: backend.CallResourceRequest{Path: ""}, expected: "http://localhost:9200/"},
+		{name: "with \"\" path and valid url", settings: es.DatasourceInfo{URL: "http://localhost:9200"}, req: backend.CallResourceRequest{Path: ""}, expected: "http://localhost:9200/"},
+		{name: "with \"\" path and valid url with path", settings: es.DatasourceInfo{URL: "http://elastic:9200/lb"}, req: backend.CallResourceRequest{Path: ""}, expected: "http://elastic:9200/lb/"},
+		{name: "with \"\" path and valid url with path and /", settings: es.DatasourceInfo{URL: "http://elastic:9200/lb/"}, req: backend.CallResourceRequest{Path: ""}, expected: "http://elastic:9200/lb/"},
 	}
 
 	for _, test := range tt {
 		t.Run(test.name, func(t *testing.T) {
 			url, err := createElasticsearchURL(&test.req, &test.settings)
 			require.NoError(t, err)
-			require.Equal(t, test.expected, url.String())
+			require.Equal(t, test.expected, url)
 		})
 	}
 }