Brume: an AWS CloudFormation deployer

---

Installation

brume is a Python package and it can be installed with Pip:

$ pip install brume

Usage

The current directory must contain a brume.yml configuration file.

Available commands

These commands always use the current AWS credentials and the stack name from the brume.yml file.

• config: Print the current stack configuration based on the brume.yml file, with the variables interpolated.
• create: Create the CloudFormation stack.
• delete: Delete the CloudFormation stack.
• deploy: Create or update the CloudFormation stack, if you only care about applying your changes and don't want to know if the stack already exists or not (can be useful for automated deployments)
• update: Update the existing CloudFormation stack.
• upload: Upload CloudFormation templates to S3.
• validate: Validate the CloudFormation templates that reside in local_path (in the YAML configuration) or the current directory.
• outputs: Get the full list of outputs
• parameters: Get the full list of parameters

The brume.yml file

The configuration file requires two configuration blocks stack and templates.

Stack

stack:
  stack_name: my-wordpress-website   # [REQUIRED] the name of the CloudFormation stack
  template_body: Main.cform          # local path to the main CloudFormation template
  template_url: https://my-bucket.s3.amazonaws.com/assets/cloudformation/Main.cform  # complete URL to the main CloudFormation template on S3

The template referenced in stack.template_body or stack.template_url is the entrypoint to your CloudFormation stack (the main or parent stack).

Templates

In case your stack is split between multiple templates, you need to upload the CloudFormation templates to S3 (e.g. using brume upload or the tool of your choice).

If you use brume upload, you need to tell brume where the templates are and where to put them. This is done via the templates section.

templates:
  s3_bucket: my-bucket            # [REQUIRED] name of the bucket in your account in which to store the templates
  s3_path: assets/cloudformation  # path of the S3 folder where the template are uploaded, defaults to `cloudformation`
  local_path: project/cfn         # local path where your CloudFormation templates are, defaults to `.`

Given the above configuration and if you have a Main.cform in project/cfn, the template would be uploaded to https://my-bucket.s3.amazonaws.com/assets/cloudformation/Main.cform.

Assets

If 'assets' configuration is present you can send additionnal resource to target s3 URI (like user data script, application config file, ...).

In your template, you can build assets url like this:

``` def getAssetUri(asset, bucketName, stackName):

return '/'.join(['s3://{}'.format(bucketName), stackName, 'assets', asset])

```

Minimal example

region: eu-west-1

stack:
  stack_name: my-wordpress-website
  template_body: Main.cform

templates:
  s3_bucket: my-bucket

Complete example

brume.yml is in fact a Jinja2 template which means you can declare variables and reuse them in the template. You can also inject environment variables by calling {{ env('MY_VAR') }}.

Also, if the current directory is a git repository (if it contains a .git/ directory), brume offers two pre-defined variables: git_commit and git_branch. Their values are taken directly from the current repository.

region: {{ env('AWS_REGION') }}

{% set stack_name = '-'.join([env('PROJECT'), env('ENVIRONMENT'), env('CLASSIFIER')]) %}
stack:
  stack_name: {{ stack_name }}

  template_body: Main.cform
  capabilities: [ CAPABILITY_IAM ]
  on_failure: DELETE

  parameters:
    Project: '{{ env('PROJECT') }}'
    Platform: '{{ env('PLATFORM') }}'
    Classifier: '{{ env('CLASSIFIER') }}'
    GitCommit: '{{ git_commit }}'
    GitBranch: '{{ git_branch }}'

  tags:
    Project: '{{ env('PROJECT') }}'
    Platform: '{{ env('PLATFORM') }}'
    Classifier: '{{ env('CLASSIFIER') }}'

templates:
  s3_bucket: my_bucket
  s3_path: {{ stack_name }}
  local_path: cloudformation

assets:
  s3_bucket: my_bucket
  s3_path: {{ stack_name }}/assets
  local_path: assets