From d0ee5427bdfac6c30ca00103f419bc1f12e05242 Mon Sep 17 00:00:00 2001
From: Julius Volz <julius.volz@gmail.com>
Date: Wed, 4 Sep 2024 21:21:29 +0200
Subject: [PATCH] Redirect /graph to /query in new UI, preserving params

Signed-off-by: Julius Volz <julius.volz@gmail.com>
---
 web/web.go | 37 +++++++++++++++++++++++++++++++++----
 1 file changed, 33 insertions(+), 4 deletions(-)

diff --git a/web/web.go b/web/web.go
index fb8d3608d..426e60903 100644
--- a/web/web.go
+++ b/web/web.go
@@ -63,8 +63,9 @@ import (
 	"github.com/prometheus/prometheus/web/ui"
 )
 
-// Paths that are handled by the React / Reach router that should all be served the main React app's index.html.
-var reactRouterPaths = []string{
+// Paths handled by the React router that should all serve the main React app's index.html,
+// no matter if agent mode is enabled or not.
+var oldUIReactRouterPaths = []string{
 	"/config",
 	"/flags",
 	"/service-discovery",
@@ -72,16 +73,31 @@ var reactRouterPaths = []string{
 	"/targets",
 }
 
+var newUIReactRouterPaths = []string{
+	"/config",
+	"/flags",
+	"/service-discovery",
+	"/alertmanager-discovery",
+	"/status",
+	"/targets",
+}
+
 // Paths that are handled by the React router when the Agent mode is set.
 var reactRouterAgentPaths = []string{
 	"/agent",
 }
 
 // Paths that are handled by the React router when the Agent mode is not set.
-var reactRouterServerPaths = []string{
+var oldUIReactRouterServerPaths = []string{
 	"/alerts",
 	"/graph",
-	"/query",
+	"/rules",
+	"/tsdb-status",
+}
+
+var newUIReactRouterServerPaths = []string{
+	"/alerts",
+	"/query", // The old /graph redirects to /query on the server side.
 	"/rules",
 	"/tsdb-status",
 }
@@ -382,6 +398,12 @@ func New(logger log.Logger, o *Options) *Handler {
 		http.Redirect(w, r, path.Join(o.ExternalURL.Path, homePage), http.StatusFound)
 	})
 
+	if o.UseNewUI {
+		router.Get("/graph", func(w http.ResponseWriter, r *http.Request) {
+			http.Redirect(w, r, path.Join(o.ExternalURL.Path, "/query?"+r.URL.RawQuery), http.StatusFound)
+		})
+	}
+
 	reactAssetsRoot := "/static/react-app"
 	if h.options.UseNewUI {
 		reactAssetsRoot = "/static/mantine-ui"
@@ -426,6 +448,13 @@ func New(logger log.Logger, o *Options) *Handler {
 	}
 
 	// Serve the React app.
+	reactRouterPaths := oldUIReactRouterPaths
+	reactRouterServerPaths := oldUIReactRouterServerPaths
+	if h.options.UseNewUI {
+		reactRouterPaths = newUIReactRouterPaths
+		reactRouterServerPaths = newUIReactRouterServerPaths
+	}
+
 	for _, p := range reactRouterPaths {
 		router.Get(p, serveReactApp)
 	}