unable to access access aws resources within docker container lambda using role based access control.

Hi,

the right way is to use only the Lambda execution role after granting it the right credentials for the services that you need.

See https://docs.aws.amazon.com/lambda/latest/dg/lambda-intro-execution-role.html

You provide an execution role when you create a function. When you invoke your function, 
Lambda automatically provides your function with temporary credentials by assuming this role. 
You don't have to call sts:AssumeRole in your function code.

Best,

Didier

This Knowledge Center article seems to be what you are looking for.