From 51a77759c1534778d9afd14ea9356908fd244caa Mon Sep 17 00:00:00 2001
From: Nikolay <nik@victoriametrics.com>
Date: Tue, 3 May 2022 12:31:31 +0200
Subject: [PATCH] lib/promscrape: adds correct http status codes for redirect
 (#2530)

standard http client accepts multiple http status codes as redirect
it should fix issue with incorrect redirects
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2482
---
 lib/promscrape/client.go | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/lib/promscrape/client.go b/lib/promscrape/client.go
index 0826d20f1..de1fe09c3 100644
--- a/lib/promscrape/client.go
+++ b/lib/promscrape/client.go
@@ -201,6 +201,15 @@ func (c *client) GetStreamReader() (*streamReader, error) {
 	}, nil
 }
 
+// checks fasthttp status code for redirect as standard http/client does.
+func isStatusRedirect(statusCode int) bool {
+	switch statusCode {
+	case 301, 302, 303, 307, 308:
+		return true
+	}
+	return false
+}
+
 func (c *client) ReadData(dst []byte) ([]byte, error) {
 	deadline := time.Now().Add(c.hc.ReadTimeout)
 	req := fasthttp.AcquireRequest()
@@ -237,7 +246,7 @@ func (c *client) ReadData(dst []byte) ([]byte, error) {
 	err := doRequestWithPossibleRetry(c.hc, req, resp, deadline)
 	statusCode := resp.StatusCode()
 	redirectsCount := 0
-	for err == nil && (statusCode == fasthttp.StatusMovedPermanently || statusCode == fasthttp.StatusFound) {
+	for err == nil && isStatusRedirect(statusCode) {
 		if redirectsCount > 5 {
 			err = fmt.Errorf("too many redirects")
 			break