TFPromote

A CLI for promoting Terraform code through environments (dev, stage, prod, etc.). Automates comparing and copying of appropriate .tf files forward from environment to environment. All stuff you can do in bash on the command line but this saves you a lot of typing and helps reduce errors when performing this monotonous task in an environment with many microservices all needing Terraform deployments.

Required Directory Structure

This tool is useful only for a very prescriptive Terraform project structure. It assumes the following:

You store Terraform in a directory for each environment
Within each directory files prefixed with that environment name (e.g. dev-) have variables specific to that environment and are expected to be different from other environments
Files not prefixed with the environment name are expected to be able to be promoted (copied) from the source to the target environment exactly as is.

This is an example of the required directory structure:

app
    terraform
        dev
            dev-variables.tf
            dev-provider.tf
            iam.tf
            ecs.tf
        stage
            stage-variables.tf
            stage-provider.tf
            iam.tf
            ecs.tf
        prod
            prod-variables.tf
            prod-provider.tf
            iam.tf
            ecs.tf

Installation

$ pip install tfpromote

Usage

TFPromote will analyze the soure and target environment, show you the differences, prompt if you want to copy .tf files from the source to the target environment.

The easiest workflow is to let TFPromote automatically determine your from and to path. Start from the target or "to path" and just use tfpromote or tfp and TFPromote will figure out the lower environment you want from your from path.

$ pwd
/devel/myapp/terraform/stage
$ tfpromote
TFPromote
From path: /devel/myapp/terraform/dev
To   path: /devel/myapp/terraform/stage
Continue? (CTRL+C to abort)

Easy as pie.

Or you can specify your from and to paths directly. Note that if you supply only the from path or to path, but not both, TFPromote will assume the current directory is the path you didn't specify.

NOTE: In prior versions you needed to specify --auto or -a to use the auto paths mode. That is now the default behavior without any arguments, so the --auto argument has been removed.

# TFPROMOTE_ENVS defaults to the below, but you can use any custom named environments by overriding
$ export TFPROMOTE_ENVS="dev,stage,prod"
$ pwd
/devel/myapp/terraform/
$ tfpromote --to ./dev --from ./stage

If you have a compare tool installed (e.g. p4merge, kdiff, beyondcompare), you can specify that with the --difftool argument.

$ tfpromote --to dev --from stage --difftool p4merge

Or set your difftool with an environment variable so you don't have to type the argument each time.

$ export TFPROMOTE_DIFFTOOL=p4merge
$ tfpromote --to dev --from stage

To see a detailed diff printed to the screen if you don't have a difftool, use the --printdiff argument.

To see a full list of arguments, use tfpromote --help.

Publishing Updates to PyPi

For the maintainer - to publish an updated version of TFPromote, increment the version number in version.py and run the following:

docker build -f ./Dockerfile.buildenv -t billtrust/tfpromote:build .
docker run --rm -it --entrypoint make billtrust/tfpromote:build publish

At the prompts, enter the username and password to the Billtrust pypi.org repo.

License

MIT License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

billtrust / terraform-promote