Problem
When using the Ruby SDK, the ECS credential server is not being picked up by default, even though the AWS_CONTAINER_CREDENTIALS_FULL_URI is supported by the Ruby SDK (see the :endpoint option).
The ECS credentials are picked up if we override the existing env var:
% export AWS_CONTAINER_CREDENTIALS_FULL_URI=http://127.0.0.1:<port>/get-credentials
% irb
irb(main):001:0> require 'aws-sdk-core'
=> true
irb(main):002:0> client = Aws::STS::Client.new
=> #<Aws::STS::Client>
irb(main):003:0> client.get_caller_identity
=>
#<struct Aws::STS::Types::GetCallerIdentityResponse <redacted>>
AWS Vault Version