fix(util-waiters): waiters should call operation once before entering waiting

Author: alexforsyth

packages/util-waiter/src/poller.spec.ts

@@ -49,18 +49,16 @@ describe(runPolling.name, () => {
     expect(mockAcceptorChecks).toHaveBeenCalled();
     expect(mockAcceptorChecks).toHaveBeenCalledTimes(1);
     expect(mockAcceptorChecks).toHaveBeenCalledWith(config.client, input);
-
-    expect(sleep).toHaveBeenCalled();
-    expect(sleep).toHaveBeenCalledTimes(1);
-    expect(sleep).toHaveBeenCalledWith(config.minDelay);
+    expect(sleep).toHaveBeenCalledTimes(0);
   });
 
   it("returns state in case of success", async () => {
     mockAcceptorChecks = jest.fn().mockResolvedValueOnce(successState);
     await expect(runPolling(config, input, mockAcceptorChecks)).resolves.toStrictEqual(successState);
-    expect(sleep).toHaveBeenCalled();
-    expect(sleep).toHaveBeenCalledTimes(1);
-    expect(sleep).toHaveBeenCalledWith(config.minDelay);
+    expect(mockAcceptorChecks).toHaveBeenCalled();
+    expect(mockAcceptorChecks).toHaveBeenCalledTimes(1);
+    expect(mockAcceptorChecks).toHaveBeenCalledWith(config.client, input);
+    expect(sleep).toHaveBeenCalledTimes(0);
   });
 
   it("sleeps as per exponentialBackoff in case of retry", async () => {
@@ -72,11 +70,13 @@ describe(runPolling.name, () => {
       .mockResolvedValueOnce(retryState)
       .mockResolvedValueOnce(retryState)
       .mockResolvedValueOnce(retryState)
+      .mockResolvedValueOnce(retryState)
       .mockResolvedValueOnce(successState);
 
     await expect(runPolling(config, input, mockAcceptorChecks)).resolves.toStrictEqual(successState);
 
     expect(sleep).toHaveBeenCalled();
+    expect(mockAcceptorChecks).toHaveBeenCalledTimes(8);
     expect(sleep).toHaveBeenCalledTimes(7);
     expect(sleep).toHaveBeenNthCalledWith(1, 2); // min delay. random(2, 2)
     expect(sleep).toHaveBeenNthCalledWith(2, 3); // random(2, 4)

packages/util-waiter/src/poller.ts

@@ -13,7 +13,8 @@ const exponentialBackoffWithJitter = (minDelay: number, maxDelay: number, attemp
 const randomInRange = (min: number, max: number) => min + Math.random() * (max - min);
 
 /**
- * Function that runs indefinite polling as part of waiters.
+ * Function that runs polling as part of waiters. This will make one inital attempt and then
+ * subsequent attempts with an increasing delay.
  * @param params options passed to the waiter.
  * @param client AWS SDK Client
  * @param input client input
@@ -24,6 +25,11 @@ export const runPolling = async <Client, Input>(
   input: Input,
   acceptorChecks: (client: Client, input: Input) => Promise<WaiterResult>
 ): Promise<WaiterResult> => {
+  const { state } = await acceptorChecks(client, input);
+  if (state !== WaiterState.RETRY) {
+    return { state };
+  }
+
   let currentAttempt = 1;
   const waitUntil = Date.now() + maxWaitTime * 1000;
   // The max attempt number that the derived delay time tend to increase.