Public Digital URL shortener

Public Digital wants to provide a URL shortening service without requiring our users to use services that soak up lots of their data.

Since there doesn't appear to be a SaaS offering that guarantees privacy, and we want to run as little software as possible we have set up an amazon s3 based redirect service.

If you know of a SaaS service that we could rely on, please let us know!

Infrastructure configuration

We use:

• AWS Route53 for DNS
• AWS CertificateManager to make it all work using https
• AWS CloudFront for caching and routing
• AWS S3 for hosting the redirects

This is all configured using terraform, other than the certificate creation process that needs to be done via the AWS Console.

We keep our configuration in a file called conf.tfvars which looks like:

site_domain = "pdlink.co"
certificate_arn = "arn:aws:acm:our-aws-certificate-details"

For more on managing terraform variables see: https://www.terraform.io/docs/configuration/variables.html

To set things up or make updates we call:

terraform apply -var-file=conf.tfvars

This assumes that you have a ~/.aws/config file with the right credentials in it. Read this if you need more info on authenticating to AWS:

https://blog.gruntwork.io/authenticating-to-aws-with-the-credentials-file-d16c0fbcbf9e

Setting up the redirections

The redirections are managed as a CSV file. To create a new redirect, add it to the file build-short-urls/pd-short-urls.csv

There are then two options for deployment:

Use Github actions

If you're editing the main PD version of this then committing your change will trigger a deployment.

If using your own clone of this then your repository will need secrets set up for AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY

With that done, pushing the updated CSV to github (or just updating it using github on the web) will trigger a deployment.

Deploy from the command line

Run:

cd build-short-urls
AWS_ACCESS_KEY_ID=<your_key> AWS_SECRET_ACCESS_KEY=<your_secret> python build_redirects.py

This assumes you are:

• running python3
• have the dependencies listed in the requirements.txt file

Any questions/suggestions

Contact james@public.digital