if you use assume role, you can do,
$ head -1 local.env.sample > local.env
$ vi local.env
$ ( cd .. && git clone https://github.com/clairvy/assume_role.git ) # you can modify your .aws setting
$ ( cd ../assume_role && docker-compose run --rm app ruby -I lib bin/assume_role ) >> local.env
$ mkdir tf
$ docker-compose run --rm app sh -x /mnt/terraforming.sh /mnt/tf
$ docker-compose run --rm tf plan