Error "The request must contain the parameter AWSAccessKeyId" if the ~/.aws/config file doesn't exist

[quelgar]

I found this problem when running on an EC2 Linux instance that received its permissions via an instance profile. The aws CLI commands worked, but I had never run aws configure.

When running an app using preview-2 on this machine, I would just get: The request must contain the parameter AWSAccessKeyId (Service: EC2Client; Status Code: 400; Error Code: MissingParameter; errors. The same app would work on my local machine where I had configured an access key.

After some digging, I narrowed it down to ProfileCredentialsProvider, which was returning null, resulting in later providers in the default chain not being tried. If I explicitly used InstanceProfileCredentialsProvider, the app would work fine via the instance profile.

To get around the problem, I ran aws configure and didn't specify any values. This created a file ~/aws/config, and after that the ProfileCredentialsProvider worked as expected, and passed the authentication down the provider chain so that InstanceProfileCredentialsProvider got a chance to run.

[shorea]

This is available in 2.0.0-preview-4