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Serverless Blog

Hello from CloudFront

As of today, this blog is now being served by Amazon S3, and cached globally by CloudFront. You can say it’s “serverless”, even if the term isn’t quite true (after all, it’s always running on someone’s server). The transition wasn’t too easy, but it was my first crack at hosting a site purely in S3, and it was a chance to learn to use CloudFront and Travis CI.

The Road to “Serverless”

When it started, this blog was hosted in a DigitalOcean Debian droplet with Caddy as its webserver. You can read the first entry here. Most recently, I transitioned to a CoreOS droplet. Somewhere along the way I put CloudFlare in front of it to handle SSL termination and caching.

I still like using CoreOS, and my DigitalOcean account isn’t going anywhere. But at least for the purposes of this blog, it doesn’t really need a full-blown server to run it, even while it’s running as a Docker container.

After writing a post, all I really need is somewhere to run Hugo to generate the static content, and then some place to upload it. $job.current has already allowed me to explore much of Amazon Web Services, so I knew I could host it in an S3 bucket as a static website1. The challenge was moving from CloudFlare to Amazon CloudFront as a CDN.

CloudFront: Plenty of Options

My experience with CloudFlare has been pretty painless. Most of the defaults just work, and they give you enough tips to get a stable, cached website with SSL enabled.

CloudFront is very powerful, but it’s easy to shoot yourself in the foot, either by setting the TTL too high and wondering why your content is missing/outdated, or invalidating the entire cached copy of your website and spending $0.005 per object (yikes). I’m still within my free year, so no money lost just yet, but I can definitely see how to shoot myself in the foot (or wallet in this case).

Getting Amazon Certificate Services to generate an SSL cert for the domain was the work of a few minutes.

Travis CI

So now that I have a bucket, it’s pretty trivial to run hugo to generate the content and upload it to s3. However, it’s kind of a pain to maintain that as a separate step in my workflow. I’d rather hand it off to an automated build system. Enter: Travis CI. Travis CI is traditionally a CI tool (go figure), but like Jenkins, it’s pretty easy to extend it to perform CD. After looking up a few examples, I was able to write a .travis.yml file that installed Hugo, built the static files, and then used s3cmd to synchronize the files with my S3 bucket.

Now, a push to master on GitHub kicks off a Travis build and an update to the S3 bucket. As long as I’m creating new entries, I don’t have to worry about stale cache entries in CloudFront.

The Future

I’m testing various tweaks to caching and building my site to see what works best, as well as keeping an eye on events in AWS that could cost me money in the future. So far, things are working pretty well.

The Code

You can see the code for this entire site on GitHub here: https://github.com/steeef/stp5blog.

Links

This blog post was very helpful in getting me started. The code snippets made it simple to modify for my needs. I got good pointers on using Travis CI with Hugo from this post.