@mapbox/cfn-config

Quickly configure and start AWS CloudFormation stacks.

Features

• CLI tool provides prompting for easy stack configuration and verification of intended changes to your stack.
• Save parameter values in a specified S3 bucket for easy reuse and sharing privately.
• Deploy templates written as either JSON or JavaScript files. JavaScript files must either export JSON directly, or export a function that asynchronously provides JSON.
• JavaScript library functions provide access to high-level routines (e.g. create, update, delete) as well as low-level utilities you can use to build your own deployment workflows.
• Optional KMS encryption of sensitive parameter values.

Prerequisites

To use cfn-config, you will need to have two (or more) S3 buckets ready:

• config bucket: this is a bucket where cfn-config will save stack configurations (parameter values) that can be reused.

• template buckets: cfn-config will upload your template file to a bucket each time you perform a create or update action. There must be a bucket in any region to which you intend to deploy CloudFormation stacks. The suggested default bucket names are:

  cfn-config-templates-{account id}-{region}
  

  If you create buckets matching this pattern in each region you wish to use, then you do not need to specify the --template-bucket option when using cfn-config's CLI tool.

CLI Installation

cfn-config includes a CLI tool for working with CloudFormation stacks. Install globally with npm to use the CLI commands:

$ npm install -g @mapbox/cfn-config

CLI Usage

$ cfn-config --help

Quickly configure and start AWS CloudFormation stacks

  USAGE: cfn-config <command> <environment> [templatePath] [options]

  command:
    - create                create a new stack
    - update                update an existing stack
    - delete                delete an existing stack
    - info                  fetch information about an existing stack
    - save                  save an existing stack's configuration

  environment:
    Any string. A stack's name is constructed as name-environment

  templatePath:
    The relative path to the CloudFormation template in JSON format, required
    for create and update commands.

  options:
    -n, --name              the stack's base name (default: current dir name)
    -r, --region            the stack's region (default: us-east-1)
    -c, --config-bucket     an S3 bucket for storing stack configurations.
                            Required for the create, update, and save commands.
    -t, --template-bucket   an S3 bucket for storing templates
                            (default: cfn-config-templates-$AWS_ACCOUNT_ID-region)
    -k, --kms               a KMS key ID for parameter encryption or
                            configuration encryption at rest on S3. If not
                            provided, no encryption will be performed. If
                            provided as a flag without a value, the default
                            key id alias/cloudformation will be used.
    -f, --force             perform a create/update/delete command without any
                            prompting, accepting all defaults
    -e, --extended          display resource details with the info command
    -x, --expand            Add CAPABILITY_AUTO_EXPAND to the changeset capabilities.
                            This allows transformation macros to be expanded on stack
                            creation or update.

JavaScript Installation

Include cfn-config into your project to incorporate/extend its functionality. Add to your project's package.json by running the following from your project's directory:

$ npm install --save @mapbox/cfn-config

Then, in your scripts:

var cfnConfig = require('@mapbox/cfn-config');

JavaScript Usage

High-level prompting routines to create, update, and delete stacks are provided, as well as to fetch detailed information about a stack or to save an existing stack's configuration to S3.

First, create a commands object:

var options = {
  name: 'my-stack', // the base name of the stack
  region: 'us-east-1', // the region where the stack resides
  templatePath: '~/my-stack/cfn.template.json', // the template file
  configBucket: 'my-cfn-configurations', // bucket for configuration files
  templateBucket: 'cfn-config-templates-123456789012-us-east-1' // bucket for templates
};

var commands = cfnConfig.commands(options);

Then, perform the desired operation:

// Create a stack called `my-stack-testing`
commands.create('testing', '~/my-stack/cfn.template.json', function(err) {
  if (err) console.error(`Create failed: ${err.message}`);
  else console.log('Create succeeded');
});

// Update the stack with a different version of the template
commands.update('testing', '~/my-stack/cfn.template-v2.json', function(err) {
  if (err) console.error(`Update failed: ${err.message}`);
  else console.log('Update succeeded');
});

// Save the stack's configuration to S3
commands.save('testing', function(err) {
  if (err) console.error(`Failed to save configuration: ${err.message}`);
  else console.log('Saved configuration');
});

// Get information about the stack
commands.info('testing', function(err, info) {
  if (err) console.error(`Failed to read stack info: ${err.message}`);
  else console.log(JSON.stringify(info, null, 2));
});

// Delete the stack
commands.delete('testing', function(err) {
  if (err) console.error(`Delete failed: ${err.message}`);
  else console.log('Delete succeeded');
});

For low-level functions, see documentation in the code for now. More legible docs are to come.

Changelog

3.3.1 - 2024-04-18

• Update diff to v5.2.0

3.3 - 2023-09-12

• Change default when confirming template changes from "No" to keep prompting the user until a valid choice is provided