Terraform wrapper script to run inside of a docker container

README.md

Run terraform in a container!

This file should just be in your path and your terraform codebase located in a folder called terraform. Then just run it like this:

terraformw init
terraformw plan -out plan.tfplan
terraformw apply plan.tfplan

Note that your AWS credentials should be in $HOME/.aws/credentials, but I guess they already are :-)

The script will ensure that the whole terraform codebase is mounted inside the container, under /app. It will then change the working directory in the container, to be the current host directory relative to the first occurence of a folder called terraform. See expected code structure below.

/code/project-foo/terraform <- folder
/code/project-foo/terraform/common <- example of module used
/code/project-foo/terraform/awesome-stack <- configuration of instances

The from within awesome-stack you can run terraformw, and the container will have /code/project-foo/terraform mounted on /app and then change working directory to be /app/awesome-stack and run terraform from there.

terraformw

#!/usr/bin/env python3

from os import getcwd,getenv
from os.path import normpath, sep, join
from itertools import takewhile
from subprocess import run
from sys import argv

def main(args):
    home = getenv("HOME")
    # Figure working directory
    cwd = getcwd()
    normalized_cwd = normpath(cwd)
    
    # Figure base path
    cwd_parts = normalized_cwd.split(sep)
    condition = lambda x: x != "terraform"
    base_path = join( sep.join( takewhile(condition, cwd_parts) ), "terraform")
    # Start docker container
    workdirectory = normalized_cwd[len(base_path)+1:]

    run([
        "docker", "run", "--rm", "-it", 
        "-e", "AWS_SHARED_CREDENTIALS_FILE=/aws_credentials",
        "-v", "{}/.aws/credentials:/aws_credentials".format(home),
        "-v", "{}:/app/".format(base_path),
        "-w", "/app/{}".format(workdirectory),
        "hashicorp/terraform:light"] + args
    )


if __name__ == "__main__":
    main(argv[1:])