Add bail-out after too many 429 errors

backend/src/utils/DecayingCounter.ts

@@ -0,0 +1,21 @@
+/**
+ * This is not related to Zeppelin's counters feature
+ */
+export class DecayingCounter {
+  protected value = 0;
+
+  constructor(protected decayInterval: number) {
+    setInterval(() => {
+      this.value = Math.max(0, this.value - 1);
+    }, decayInterval);
+  }
+
+  add(count = 1): number {
+    this.value += count;
+    return this.value;
+  }
+
+  get(): number {
+    return this.value;
+  }
+}