Content Delivery Network AWS Module

This repo contains a Module for deploying a Content Delivery Network (CDN) on Amazon Web Services (AWS) using Terraform.

A content delivery network (CDN) is a system of distributed servers (network) that deliver pages and other Web content to a user, based on the geographic locations of the user, the origin of the webpage and the content delivery server.

This module can create your CDN in a manner compliant with best practices for frameworks such as GatsbyJS where HTML files are not cached, as per their recommendation. This is done with a pair of Lambda@Edge functions connected to the CloudFront distribution. Please note that at this time this functionality is only available in the AWS us-east-1 region.

Usage

This module can be used as follows

module "content-delivery-network" {
  source  = "ReidWeb/content-delivery-network/aws"

  env = "dev"
  domain_name = "mysite.dev.aws.example.com"
  additional_domains = ["www.mysite.dev.aws.example.com", "blog.dev.aws.example.com"]
  route53_zone_name = "dev.aws.example.com"
  region                  = "eu-west-1"
  shared_credentials_file = "/Users/yourUser/.aws/credentials"
  profile                 = "dev-profile"
  env                     = "Dev"
}

Note that Lambda@Edge is currently only supported in us-east-1

Inputs

Name	Description	Type	Default	Required
env	Deployment environment of application, will be included in resource names, and tags	string	-	yes
profile	Profile to use - required because we have to do some fiddling with the provider object to create certs in the right region.	string	-	yes
shared_credentials_file	Shared credentials file to use - required because we have to do some fiddling with the provider object to create certs in the right region.	string	-	yes
region	Shared credentials file to use - required because we have to do some fiddling with the provider object to create certs in the right region.	string	us-east-1	no
domain_name	Primary domain for this distribution.	string	""	no
additional_domains	Additional domains for this distribution.	list	[]	no
route53_zone_name	The name of your Route 53 zone in which to create the records	string	""	no
provision_lambdas	Whether to provision the custom event Lambdas, or use a basic CloudFront distribution	string	"true"	no

Be sure to read the inputs documentation before use - as omission of certain parameters will lead to behaviour changing.

Outputs

Name	Description
headers_lambda_qualified_arn	Qualified ARN of headers Lambda
paths_lambda_qualified_arn
lambda_role_arn	ARN of role assigned to Lambdas
bucket_id	ID for Origin S3 Bucket
bucket_domain_name	Domain name for Origin S3 Bucket
certificate_id	ID of certfificate provisioned in ACM
certificate_arn	ARN of certificate provisioned in ACM
cloudfront_dist_id	ID of CloudFront Distribution
cloudfront_dist_zone_id	Zone ID of CloudFront Distribution
cloudfront_domain	.cloudfront.net domain of Distribution
cloudfront_origin_iam_arn	CloudFront Origin Acess Identity

FAQ

What's a module?

A Module is a canonical, reusable, best-practices definition for how to run a single piece of infrastructure, such as a database or server cluster. Each Module is created using Terraform, and includes automated tests, examples, and documentation. It is maintained both by the open source community and companies that provide commercial support.

Instead of figuring out the details of how to run a piece of infrastructure from scratch, you can reuse existing code that has been proven in production. And instead of maintaining all that infrastructure code yourself, you can leverage the work of the Module community to pick up infrastructure improvements through a version number bump.

What code is included in this module:

• lambda-iam-role: This module creates the necessary IAM roles and policies for the Lambda functions to log to CloudWatch and to be invoked as part of the CloudFront distribution's event sequence using Lambda@Edge.
• lambdas: This module provisions the Lambda functions for handling events from CloudFront via Lambda@Edge.
• certificate: This module provisions a certificate for the domains specified by the user using Amazon Certificate Manager (ACM).
• bucket: This module provisions the Amazon S3 Bucket that will be used as the 'origin' for the CDN, along with the necessary policy that permits the CloudFront distribution to serve objects from it.
• cloudfront-distribution: This module creates the Amazon CloudFront 'distribution' from which your resources will be accessed, using the user specified domains when provided.
• bucket-iam-policy: This module creates the IAM policy that allows the CloudFront Origin to access the S3 bucket.
• route53-records: This module creates the Amazon Route 53 alias records for the domains specified targeting the CloudFront distribution.

How do I contribute to this Module?

Contributions are very welcome! Check out the Contribution Guidelines for instructions.

How is this Module versioned?

This Module follows the principles of Semantic Versioning. You can find each new release, along with the changelog, in the Releases Page.

During initial development, the major version will be 0 (e.g., 0.x.y), which indicates the code does not yet have a stable API. Once we hit 1.0.0, we will make every effort to maintain a backwards compatible API and use the MAJOR, MINOR, and PATCH versions on each release to indicate any incompatibilities.

Trademarks

All other trademarks referenced herein are the property of their respective owners.

License

This code is released under the MIT License. Please see LICENSE for more.

Copyright © 2018 Peter Reid