feat: implement graceful shutdown handling

src/lib/shutdown.ts

@@ -0,0 +1,30 @@
+import { logger } from "@lib/logger";
+
+let shuttingDown = false;
+let activeTransactions = 0;
+
+export const isShuttingDown = () => shuttingDown;
+export const setShuttingDown = (value: boolean) => {
+    shuttingDown = value;
+};
+
+export const incrementTransactions = () => {
+    activeTransactions++;
+};
+
+export const decrementTransactions = () => {
+    activeTransactions--;
+};
+
+export const getActiveTransactions = () => activeTransactions;
+
+export const waitForTransactions = async (timeoutMs: number = 10000) => {
+    const start = Date.now();
+    while (activeTransactions > 0) {
+        if (Date.now() - start > timeoutMs) {
+            logger.warn(`Shutdown timed out waiting for ${activeTransactions} transactions after ${timeoutMs}ms`);
+            break;
+        }
+        await new Promise(resolve => setTimeout(resolve, 100));
+    }
+};