fix(hideBefore): only delete shadow if the date changes

Author: coderbyheart

cdk/resources/DeviceStorage.ts

@@ -18,7 +18,7 @@ export class DeviceStorage extends Construct {
 					? RemovalPolicy.DESTROY
 					: RemovalPolicy.RETAIN,
 			pointInTimeRecovery: true,
-			stream: DynamoDB.StreamViewType.NEW_IMAGE,
+			stream: DynamoDB.StreamViewType.NEW_AND_OLD_IMAGES,
 		})
 		this.devicesTable.addGlobalSecondaryIndex({
 			indexName: this.devicesTableFingerprintIndexName,

cdk/resources/UpdateDevice.ts

@@ -72,6 +72,7 @@ export class UpdateDevice extends Construct {
 									S: [{ exists: true }],
 								},
 							},
+							OldImage: [{ exists: true }],
 						},
 					}),
 				],

lambda/onHideData.ts

@@ -15,15 +15,26 @@ export const handler = middy()
 	.handler(async (event: DynamoDBStreamEvent): Promise<void> => {
 		for (const record of event.Records) {
 			const newImage = record.dynamodb?.NewImage
-			if (newImage === undefined) {
+			const oldImage = record.dynamodb?.OldImage
+			if (newImage === undefined || oldImage === undefined) {
 				continue
 			}
+			const { hideDataBefore: oldHideDataBefore } = unmarshall(
+				oldImage as Record<string, AttributeValue>,
+			) as { hideDataBefore: string }
 			const { deviceId, hideDataBefore } = unmarshall(
 				newImage as Record<string, AttributeValue>,
 			) as {
 				deviceId: string
 				hideDataBefore: string
 			}
+
+			if (hideDataBefore === oldHideDataBefore) {
+				console.log(
+					`No change in hideDataBefore for device ${deviceId}, skipping...`,
+				)
+				continue
+			}
 			console.log(
 				`Hiding data before ${hideDataBefore} for device ${deviceId}...`,
 			)