fix: max session policy is not shown for 20 sec

- If the resource broker is not ready (when `globalThis`.backendaiclient
  is `undefined`), retry to get the `concurrency_max` after 2500 ms.
- Prevent silent failure in resource aggregation in the broker.

src/components/backend-ai-resource-broker.ts

@@ -349,6 +349,10 @@ export default class BackendAiResourceBroker extends BackendAIPage {
    *
    */
   async _refreshResourcePolicy() {
+    if (!globalThis.backendaiclient) {
+      // To prevent a silent failure when the client is not ready in aggregating resources.
+      return Promise.resolve(false);
+    }
     if (Date.now() - this.lastResourcePolicyQueryTime < 2000) {
       return Promise.resolve(false);
     }
@@ -482,7 +486,7 @@ export default class BackendAiResourceBroker extends BackendAIPage {
    * @param {string} from - set the value for debugging purpose.
    */
   async _aggregateCurrentResource(from = '') {
-    if (this.aggregate_updating) {
+    if (!globalThis.backendaiclient || this.aggregate_updating) {
       return Promise.resolve(false);
     }
     if (Date.now() - this.lastQueryTime < 1000) {

src/components/backend-ai-resource-monitor.ts

@@ -532,7 +532,16 @@ export default class BackendAiResourceMonitor extends BackendAIPage {
     }
     return this.resourceBroker
       ._refreshResourcePolicy()
-      .then(() => {
+      .then((resolvedValue) => {
+        if (resolvedValue === false) {
+          setTimeout(() => {
+            // Retry to get the concurrency_max after a while if resource broker
+            // is not ready. When the timeout is 2000, it delays the display of
+            // other resource's allocation status. I don't know why, but I just
+            // set it to 2500.
+            this._refreshResourcePolicy();
+          }, 2500);
+        }
         this.concurrency_used = this.resourceBroker.concurrency_used;
         // this.userResourceLimit = this.resourceBroker.userResourceLimit;
         this.concurrency_max =