Can AWS API Gateway cache invalidate specific entr

Question

I have used AWS API Gateway with the endpoint as a lambda function. I have enabled the cache functionality provided by API Gateway, to reduce both response time & the number of calls forwarded to my lambda function.

The lambda function queries another data store to return data. If data is not found, an asynchronous call is made to update the data store and "data not found" is returned to the caller. Now the API Gateway is even caching this result, which we do not want to happen. This results in the cache always returning "data not found" for its lifetime (1 hr TTL), even though data is updated asynchronously in the data store.

I'm aware of the request header (Cache-Control: max-age=0) which can invalidate cache and get response directly from Lambda, as mentioned in this documentation page.

But this will not be useful because the caller is unaware whether data is present in data store or not and hence cannot selectively send such request header.

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So, my 2 questions are:

1. Does the API Gateway caches other HTTP response as well, like 404 (apart from 200)?
2. Is it possible to tell the API Gateway not to cache specific responses?

Answer 1

1. As you observed, API Gateway caches the result of your endpoint regardless of the status code.

2. No, not at this time. I can bounce the idea to see if this is something we can support in the future.

Even if API Gateway conditionally did not cache the 404, the caller would need to call the endpoint again anyway, so why not return the result synchronously? This pattern is how most cached APIs that I'm aware of behave and would allow your API to work with what API Gateway offers today.