cf_cdn_service_broker

Cloud Foundry CDN Service Broker

A Cloud Foundry service broker that uses AWS CloudFront to proxy traffic from a domain that the user controls (the domain) to an existing Cloud Foundry application or external URL. Traffic is encrypted using an SSL certificate generated by ACM.

Deployment

Automated

The easiest/recommended way to deploy the broker is via the Concourse pipeline.

1. Create a ci/credentials.yml file, and fill in the templated values from the pipeline.

2. Deploy the pipeline.

   fly -t lite set-pipeline -n -c ci/pipeline.yml -p deploy-cdn-broker -l ci/credentials.yml
   

Manual

1. Clone this repository, and cd into it.

2. Target the space you want to deploy the broker to.

   $ cf target -o <org> -s <space>
   

3. Set the environment_variables listed in the deploy pipeline.

4. Deploy the broker as an application.

   $ cf push
   

5. Register the broker.

   $ cf create-service-broker cdn-route [username] [password] [app-url] --space-scoped
   

Usage

1. Target the space your application is running in.

   $ cf target -o <org> -s <space>
   

2. Add your domain to your Cloud Foundry organization:

   $ cf create-domain <org> my.domain.gov
   ```
   
   

3. Create a service instance.

   $ cf create-service cdn-route cdn-route my-cdn-route -c '{"domain": "my.domain.gov"}'
   
   Create in progress. Use 'cf services' or 'cf service my-cdn-route' to check operation status.
   

   If you have more than one domain you can pass a comma-delimited list to the domain parameter, just keep in mind that the broker will wait until all domains are CNAME'd:

   $ cf create-service cdn-route cdn-route my-cdn-route -c '{"domain": "my.domain.gov,www.my.domain.gov"}'
   
   Create in progress. Use 'cf services' or 'cf service my-cdn-route' to check operation status.
   

4. Get the DNS instructions.

   $ cf service my-cdn-route
   
   Last Operation
   Status: create in progress
   Message: Provisioning in progress; CNAME domain "my.domain.gov" to "d3kajwa62y9xrp.cloudfront.net."
   

5. Create/update your DNS configuration.

6. Wait up to 30 minutes for the CloudFront distribution to be provisioned and the DNS changes to propagate.

7. Visit my.domain.gov, and see that you have a valid certificate (i.e. that visiting your site in a modern browser doesn't give you a certificate warning).

8. Add your domain to a Cloud Foundry application:

   $ cf map-route <app> my.domain.gov
   

The default TTL for the CloudFront distribution is 0. To change this, you can pass it as a parameter:

$ cf create-service cdn-route cdn-route my-cdn-route \
    -c '{"domain": "my.domain.gov", "default_ttl": 12345}'

Create in progress. Use 'cf services' or 'cf service my-cdn-route' to check operation status.

Cookie Forwarding

If you do not want cookies forwarded to your origin, you'll need to add another parameter:

$ cf create-service cdn-route cdn-route my-cdn-route \
    -c '{"domain": "my.domain.gov", "cookies": false}'

Create in progress. Use 'cf services' or 'cf service my-cdn-route' to check operation status.

Header Forwarding

CloudFront forwards a limited set of headers by default. If you want extra headers forwarded to your origin, you'll want to add another parameter. Here we forward both the User-Agent and Referer headers:

$ cf create-service cdn-route cdn-route my-cdn-route \
    -c '{"domain": "my.domain.gov", "headers": ["User-Agent", "Referer"]}'

Create in progress. Use 'cf services' or 'cf service my-cdn-route' to check operation status.

CloudFront can forward up to 10 custom headers. Because this broker automatically forwards the Host header when not using a custom origin, you can whitelist up to nine headers by default; if using a custom origin, you can whitelist up to 10 headers. If you want to exceed this limit or forward all headers, you can use a wildcard:

$ cf create-service cdn-route cdn-route my-cdn-route \
    -c '{"domain": "my.domain.gov", "headers": ["*"]}'

Create in progress. Use 'cf services' or 'cf service my-cdn-route' to check operation status.

When making requests to the origin, CloudFront's caching mechanism associates HTTP requests with their response. The more variation within the forwarded request, the fewer cache hits and the less effective the cache. Limiting the headers forwarded is therefore key to cache performance. Caching is disabled altogether when using a wildcard.

Debugging

By default, Cloud Controller will expire asynchronous service instances that have been pending for over one week. If your instance expires, run a dummy update to restore it to the pending state so that Cloud Controller will continue to check for updates:

cf update-service my-cdn-route -c '{"timestamp": 20161001}'

Tests

go test -v $(go list ./... | grep -v /vendor/)

Contributing

See CONTRIBUTING for additional information.

Understanding the CDN broker state changes

The CDN broker is highly asynchronous, and deals with AWS CloudFront and ACM simultaneously. For that reason, it can be difficult to reason about the states it has and how it transitions between them. The below diagram is intended to help clarify that.

Public domain

This project is in the worldwide public domain. As stated in CONTRIBUTING:

This project is in the public domain within the United States, and copyright and related rights in the work worldwide are waived through the CC0 1.0 Universal public domain dedication.

All contributions to this project will be released under the CC0 dedication. By submitting a pull request, you are agreeing to comply with this waiver of copyright interest.