Reload credentials from the AWS credential file if they have changed on disk

[kdaily]

Related issues:

• Credentials files are only read once and are never reread boto/botocore#704
• Allow refreshing credentials from shared credentials file if file is modified boto/botocore#2450
• Reload ProfileCredentialsProvider if ProfileFile changes on disk aws-sdk-java-v2#1754

We require short term credentials to be used for all API calls. As an easy way to deal with this, we have been writing credentials to a credentials file continually every X minutes and relying on the default search order for finding credentials. That way, we don't have to write any specific authentication code inside the app.

The current solution is for users to write their own credential provider to do this, as demonstrated here (for the Python SDK):

boto/botocore#704 (comment)

[reegnz]

Another solution instead of writing your own credential provider is to use credential_process which might be easier to do if the tool you're using is not yours to modify and therefore you cannot simply add a custom credential provider (eg. using terraform, or aws-cli in a shell script).

Would definitely be great to watch the credential file for changes though, then you don't even need an aws config file if you're using the default location of the shared credentials file.

[RyanFitzSimmonsAK]

Transferring issue to the aws-cli repo for tracking going forward.