FS: Check session expiration and rotate if needed (#114433)

* FS: Check session expiration and rotate if needed

* Remove unused return values

pkg/services/frontend/index.html

@@ -239,6 +239,30 @@
 
         const CHECK_INTERVAL = 1 * 1000;
 
+        function getCookie(name) {
+          const cookies = document.cookie.split(";").map(c => c.trim());
+
+          for (const cookie of cookies) {
+            if (cookie.startsWith(name + "=")) {
+              return cookie.substring(name.length + 1);
+            }
+          }
+
+          return null;
+        }
+
+        function getSessionExpiration() {
+          const value = getCookie("grafana_session_expiry") || "0";
+          const realExpiresSeconds = parseInt(value, 10);
+          const expiresSeconds = Math.max(realExpiresSeconds - 10, 0); // Rotate 10s before the real expiration
+          const expiration = new Date(expiresSeconds * 1000);
+          return expiration;
+        }
+
+        async function rotateSession() {
+          await fetch('/api/user/auth-tokens/rotate', { method: 'POST' });
+        }
+
         /**
          * Fetches boot data from the server. If it returns undefined, it should be retried later.
          * Will return a rejected promise on unrecoverable errors.
@@ -295,6 +319,19 @@
         function loadBootData() {
           return new Promise((resolve, reject) => {
             const attemptFetch = async () => {
+              try {
+                const sessionExpiration = getSessionExpiration();
+                const now = new Date();
+
+                // If the session has expired, don't continue trying to fetch boot data
+                if (now >= sessionExpiration) {
+                  await rotateSession();
+                }
+              } catch (error) {
+                // Just ignore any errors in session rotation. The user can just log in again.
+                console.warn("Failed to rotate session", error);
+              }
+
               try {
                 const bootData = await fetchBootData();