VIA-831 LC flush hydrator log to capture final entry

Author: liming-cheung-nhs

src/_lambda/content-cache-hydrator/handler.ts

@@ -191,12 +191,21 @@ const runContentCacheHydrator = async (event: ContentCacheHydratorEvent) => {
   }
 };
 
+const flushLogs = () =>
+  new Promise<void>((resolve) => {
+    logger.flush(() => resolve());
+  });
+
 export const handler = async (event: object, context: Context): Promise<void> => {
   const requestContext: RequestContext = {
     traceId: context.awsRequestId,
     nextUrl: "",
     sessionId: "content-cache-hydrator",
   };
 
-  await asyncLocalStorage.run(requestContext, () => runContentCacheHydrator(event));
+  try {
+    await asyncLocalStorage.run(requestContext, () => runContentCacheHydrator(event));
+  } finally {
+    await flushLogs();
+  }
 };