update PinpointProvider retry endpointUpdate logic (aws-amplify#4845)

* update retry endpoint update logic

* Add unit test for endpoint update retry

packages/analytics/__tests__/Providers/AWSPinpointProvider-unit-test.ts

@@ -771,6 +771,51 @@ describe('AnalyticsProvider test', () => {
 				expect(reject).toBeCalledWith(mockError);
 				spyon.mockRestore();
 			});
+
+			test('Exceeded maximum endpoint per user count', async () => {
+				const analytics = new AnalyticsProvider();
+				const mockExceededMaxError = {
+					statusCode: 400,
+					message: 'Exceeded maximum endpoint per user count 10',
+				};
+
+				analytics.configure(options);
+
+				const spyonUpdateEndpoint = jest
+					.spyOn(Pinpoint.prototype, 'updateEndpoint')
+					// Reject with error the first time we execute updateEndpoint
+					.mockImplementationOnce(params => ({
+						promise: jest.fn().mockRejectedValue(mockExceededMaxError),
+					}))
+					// Succeed on the second attempt (i.e. after we go through _retryEndpointUpdate)
+					.mockImplementationOnce(params => ({
+						promise: jest.fn(() => Promise.resolve('data')),
+					}));
+
+				jest
+					.spyOn(Credentials, 'get')
+					.mockImplementationOnce(() => Promise.resolve(credentials));
+
+				jest
+					.spyOn(AnalyticsProvider.prototype, '_removeUnusedEndpoints')
+					.mockImplementationOnce(() => ({
+						promise: jest.fn().mockResolvedValue(true),
+					}));
+
+				const spyonRetryEndpointUpdate = jest.spyOn(
+					AnalyticsProvider.prototype,
+					'_retryEndpointUpdate'
+				);
+
+				const params = { event: { name: '_update_endpoint', immediate: true } };
+
+				await analytics.record(params, { resolve, reject });
+
+				expect(spyonUpdateEndpoint).toHaveBeenCalledTimes(2); // 1 failed + 1 successful call
+				expect(spyonRetryEndpointUpdate).toHaveBeenCalled();
+
+				spyonUpdateEndpoint.mockRestore();
+			});
 		});
 	});
 });

packages/analytics/src/Providers/AWSPinpointProvider.ts

@@ -491,13 +491,21 @@ export default class AWSPinpointProvider implements AnalyticsProvider {
 		const { params } = endpointObject;
 
 		// TODO: implement retry with exp back off once exp function is available
+		const {
+			config: { resendLimit },
+		} = params;
+
+		params.resendLimit =
+			typeof params.resendLimit === 'number' ? params.resendLimit : resendLimit;
 
 		if (params.resendLimit-- > 0) {
 			logger.debug(
 				`resending endpoint update ${params.event.eventId} with ${params.resendLimit} retry attempts remaining`
 			);
 			// insert at the front of endpointBuffer
-			this._endpointBuffer.unshift(endpointObject);
+			this._endpointBuffer.length
+				? this._endpointBuffer.unshift(endpointObject)
+				: this._updateEndpoint(endpointObject);
 			return;
 		}
 
@@ -512,6 +520,7 @@ export default class AWSPinpointProvider implements AnalyticsProvider {
 
 	private async _removeUnusedEndpoints(appId, userId) {
 		return new Promise((res, rej) => {
+			// TODO: re-write with Promise (during refactor pt. 2)
 			this.pinpointClient.getUserEndpoints(
 				{
 					ApplicationId: appId,