Support authentication from IAM Roles

[akhan4u]

Feature Request

Is your feature request related to a problem? Please describe.

aws-cost is unable to run on accounts that authenticate via IAM Role-based authentication.

For example:

[profile marketingadmin]
role_arn = arn:aws:iam::123456789012:role/marketingadminrole
source_profile = user1

Describe the solution you'd like

aws-cost is able to run with IAM Role based authentication.

Describe alternatives you've considered

I've tried setting the AWS AUTH ENV Vars which I get post-authenticating from the IAM Role but it still doesn't work

AWS_PROFILE=
AWS_REGION=
AWS_SECRET_ACCESS_KEY=
AWS_ACCESS_KEY_ID=
AWS_SESSION_TOKEN=

It gives the same error

    Error:
    
    Could not find the AWS credentials in the following files for the profile "marketingadmin":
      ~/.aws/credentials
      ~/.aws/config

    If the config files exist at different locations, set the following environment variables:
      AWS_SHARED_CREDENTIALS_FILE
      AWS_CONFIG_FILE

    You can also configure the credentials via the following command:
      aws configure --profile superdev

    You can also provide the credentials via the following options:
      --access-key
      --secret-key
      --region
    

Are you willing to resolve this issue by submitting a Pull Request?

• Yes, I have the time, and I know how to start.
• Yes, I have the time, but I don't know how to start. I would need guidance.
• No, I don't have the time, although I believe I could do it if I had the time...
• No, I don't have the time and I wouldn't even know how to start.