CloudFormation + CodePipeline Template Configuration For CLI Tools

Making development closer to production use of CodePipeline

See Limitations section towards the bottom

Supported CLI Tools

• aws cloudformation https://aws.amazon.com/cli/
  • deploy | create-stack | create-change-set | create-stack-instances | create-stack-set | update-stack | update-stack-instances | update-stack-set
• aws serverlessrepo create-cloud-formation-change-set https://aws.amazon.com/cli/
• sam deploy https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/serverless-sam-cli-install.html
• rain deploy https://github.com/aws-cloudformation/rain

Fed up of the following commands all differing in their parameter overrides and tags parameter formats? and them all differing from how CloudFormation Actions in CodePipeline are configured?

Then do one of these:

$ tc aws cloudformation deploy ...
$ tc aws cloudformation create-change-set ... 
$ tc sam deploy ... 
$ tc rain deploy ...

With a template configuration file template-configuration/default.json (see https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/continuous-delivery-codepipeline-cfn-artifacts.html#w2ab1c21c17c15)

{
  "Parameters": {
    "Key": "Value"
  },
  "Tags": {
    "TagKey": "TagValue"
  }, 
  "StackPolicy": {
    "Statement": [
      {
        "Effect": "Allow",
        "NotAction": "Update:Delete",
        "Principal": "*",
        "Resource": "*"
      }
    ]
  }
}

And do away with your flakey non-production-like deploy scripts, and stop doing these:

$ aws cloudformation deploy \
  --parameter-overrides \
    Key=Value \
    Key2=Value2 \
  ...

$ aws cloudformation create-change-set \
  --parameters \
    ParameterKey=Key,ParameterValue=Value \
    ParameterKey=Key2,ParameterValue=Value2 \
  ...

$ sam deploy \
  --parameter-overrides \
    ParameterKey=Key,ParameterValue=Value \
    ParameterKey=Key2,ParameterValue=Value2 \
  ...

$ rain \
  --params \
    Key=Value,Key2=Value2

Implicit Proxy

Add the following to your shell rc/profile file to replace aws, sam, and/or rain with implicit tc proxying (e.g. ~/.bashrc, ~/.zshrc, etc)

aws () { template-configuration "$0" "$@" }
sam () { template-configuration "$0" "$@" }
rain () { template-configuration "$0" "$@" }

Then tc is implicit and no longer needed

$ aws cloudformation deploy ...
$ aws cloudformation create-change-set ...
$ sam deploy ...
$ rain deploy ...

Limitations

• only supports commands without global arguments between them (where they would otherwise be supported)
  • supported aws cloudformation deploy ... --profile <profile> --region <region>
  • not-supported aws --profile <profile> --region <region> cloudformation deploy ...
• only supports proxying to help commands where help arguments are the last argument e.g. aws cloudformation deploy help
• does not and does not plan to support merging each commands existing parameter arguments with a template configuration file
• [ ] add support for tc --parameters ... [cmd ...] for 1 single way override template configuration file values
• [ ] test / add support for parameters with quoted values
• [ ] support UsePreviousValue
• [ ] tc help --help -h
• [ ] support StackPolicy for those commands that support it, and maybe do 2nd api call if needed for those where it is not

Arguments

Some arguments can come before the proxied command e.g. tc <here> aws ...

• tc init create a template-configuration/default.json file, with optional additional --config argument
• --debug echos out the command that is also ran
• --dryrun only echo out the command that would otherwise be ran – implies --debug
• --config <configuration-file> override template-configuration/default.json with another local file path
  • e.g. tc --config template-configuration/test.json sam deploy ...