From e03a924236366cdea68c2265fc4f208bf32453b8 Mon Sep 17 00:00:00 2001
From: Aliaksandr Valialkin <valyala@victoriametrics.com>
Date: Sat, 1 Oct 2022 16:52:27 +0300
Subject: [PATCH] app/vmauth: do not remove trailing slash from the proxied
 path

This should fix the issue with opening VMUI at /vmui/ page.

See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1752
---
 app/vmauth/target_url.go | 11 ++++++++++-
 docs/CHANGELOG.md        |  1 +
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/app/vmauth/target_url.go b/app/vmauth/target_url.go
index be5134b9c..3df9a2e80 100644
--- a/app/vmauth/target_url.go
+++ b/app/vmauth/target_url.go
@@ -39,10 +39,19 @@ func createTargetURL(ui *UserInfo, uOrig *url.URL) (*url.URL, []Header, error) {
 	u := *uOrig
 	// Prevent from attacks with using `..` in r.URL.Path
 	u.Path = path.Clean(u.Path)
+	if !strings.HasSuffix(u.Path, "/") && strings.HasSuffix(uOrig.Path, "/") {
+		// The path.Clean() removes traling slash.
+		// Return it back if needed.
+		// This should fix https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1752
+		u.Path += "/"
+	}
 	if !strings.HasPrefix(u.Path, "/") {
 		u.Path = "/" + u.Path
 	}
-	u.Path = strings.TrimSuffix(u.Path, "/")
+	if u.Path == "/" {
+		// See https://github.com/VictoriaMetrics/VictoriaMetrics/pull/1554
+		u.Path = ""
+	}
 	for _, e := range ui.URLMap {
 		for _, sp := range e.SrcPaths {
 			if sp.match(u.Path) {
diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index a1f0cf9fb..9ff5fe932 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -48,6 +48,7 @@ See [these docs](https://docs.victoriametrics.com/Cluster-VictoriaMetrics.html#m
 * FEATURE: [vmagent](https://docs.victoriametrics.com/vmagent.html): accept data ingestion requests via paths starting from `/prometheus` prefix in the same way as [VictoriaMetrics does](https://docs.victoriametrics.com/#how-to-import-time-series-data). For example, `vmagent` now accepts Prometheus `remote_write` data via both `/api/v1/write` and `/prometheus/api/v1/write`. This simplifies switching between single-node VictoriaMetrics and `vmagent`.
 * FEATURE: [vmagent](https://docs.victoriametrics.com/vmagent.html): add `external_labels` from `global` section at `-promscrape.config` after the [relabeling](https://docs.victoriametrics.com/vmagent.html#relabeling) is applied to scraped metrics. This aligns with Prometheus behaviour. Previously the `external_labels` were added to scrape targets, so they could be modified during relabeling. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3137).
 
+* BUGFIX: [vmauth](https://docs.victoriametrics.com/vmauth.html): properly handle request paths ending with `/` such as `/vmui/`. Previously `vmui` was dropping the traling `/`, which could prevent from using `vmui` via `vmauth`. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1752).
 * BUGFIX: [vmagent](https://docs.victoriametrics.com/vmagent.html): properly encode query params for aws signed requests, use `%20` instead of `+` as api requires. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3171).
 * BUGFIX: [vmagent](https://docs.victoriametrics.com/vmagent.html): properly parse relabel config when regex ending with escaped `$`. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3131).
 * BUGFIX: [MetricsQL](https://docs.victoriametrics.com/MetricsQL.html): properly calculate `rate_over_sum(m[d])` as `sum_over_time(m[d])/d`. Previously the `sum_over_time(m[d])` could be improperly divided by smaller than `d` time range. See [rate_over_sum() docs](https://docs.victoriametrics.com/MetricsQL.html#rate_over_sum) and [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3045).