AWS Parameter caching layer error

Question

We are currently using the AWS Parameter and Secrets Lambda extension for one of our lambdas. It is based on the guidance provided in the following AWS blog post: https://aws.amazon.com/blogs/compute/using-the-aws-parameter-and-secrets-lambda-extension-to-cache-parameters-and-secrets/. 
The setup: Python 3.9, architecture x86_64 , layer arn: arn:aws:lambda:eu-west-1:015030872274:layer:AWS-Parameters-and-Secrets-Lambda-Extension:4.

While the extension generally works well, every now and then we have been experiencing intermittent errors when trying to parse the response data returned by the extension's cache.

> json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)
 
This error occurs when we attempt to load the response data using the following piece of code:

> response = json.loads(response.data)

That suggests the cache may sometimes contain invalid characters or empty strings. We can implement retry policy, but what can be a root cause of this issue ?

Answer

It's almost impossible to guess the root cause of this issue given the provided information. It is always a good idea to handle known error-cases. If you log the response you may get additional information that leads you to the root cause.

To handle the error you could do:

    try:
        result = json.loads(response.data)
    except json.decoder.JSONDecodeError:
        log(response)
        result = {}

To handle the error you could do:
```python
    try:
        result = json.loads(response.data)
    except json.decoder.JSONDecodeError:
        log(response)
        result = {}
```

AWS Parameter caching layer error

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