Handling Terraform provider credentials in distributed environment with InSpec and remote state

Does anyone have any cool ideas on how to handle Terraform provider credentials for AWS given these use cases:

• Distributed environments (prod/pre/qa/test/dev) with individual AWS accounts
• S3 backend remote state for all environments in a single AWS account
• Test Kitchen using InSpec.

My current workflow requires changing the AWS_ACCESS_KEY and AWS_SECRET_KEY depending on the operation:

• terraform init - requires access to S3 backend remote state
• terraform plan/apply - requires access to specific environment + remote state
  • Non-functional (a single set of credentials doesn't have access to both the env + remote state)
• kitchen converge - requires access to test environment + remote state
  • Non-functional (same reason as above)
• kitchen verify - requires access to test environment.

Ideas

• I wish I could store the S3 remote state in the respective environment accounts but variables don't seem to be supported in the Terraform backend configuration.

You will need the main account to be able to assume a role on each env account to perform the changes, while the remote main account will keep all states. This is a good way to work with terraform worspaces Assuming you have two workspaces, prod and dev, you can try something like this:

variable "workspace_roles" {
  default = {
    dev  = "arn:aws:iam::<dev account id>:role/terra_role"
    prod = "arn:aws:iam::<prodaccount id>:role/terra_role"
  }
}

provider "aws" {
 assume_role = var.workspace_roles[terraform.workspace]
}