Static sites and Functions

This is the fifth and last part of a series of posts I am writing about building a static site with VueJS. In this post, I will walk-through how you could use Functions-as-a-Service for your next project…or your current too.

Static sites typically don’t get all of the infrastructure attention, that other stuff does. Many developers still think that SPAs, whether static sites or not, need to be hosted with an always-running server infrastructure. It is unnecessary. With the advent of ServiceWorkers and the Progressive Web App movement, you really don’t need a server running all of the time.

Most devs are familiar with using a CMS like WordPress and then buying a domain to serve a website. Most websites don’t need all of that infrastructure. The price is a modest $4/mo according to their pricing page, you just get the basic with the paid plan. Not a big deal, though. But if you wanted to do SEO, custom analytics etc., you are looking at the next pricing tier or perhaps the most expensive one, at $25/mo, if you are looking for a few more knobs/levers to turn.

This is the architecture I used for Net Your Problem.

Static websites architecture with Functions-Page-1
Fig.1 – A simple cloud architecture for SPAs.

I have automated the part where I build the VueJS app and upload it to the Azure Storage account using a PowerShell script (see this gist), which is purely based on the AzureRM PS module.

Great. Now, let’s talk about how these infrastructure systems talk to each other, to cohesively power your next project.

The inner details

A CDN works by aggressively caching static resources (JS, CSS, HTML, PNGs etc.). You can also give a hint to a CDN service to cache additional mime-types by setting the Cache-Control header attribute. A typical CDN service has “edge” nodes all over the world. When you provision a CDN service from any of the cloud providers, you are not choosing the edge nodes in a particular region. CDN services are globally distributed, by default. Each CDN service does their billing differently. For example, I know that the Azure CDN service offers a tiered pricing model based on a group of countries in each tier. So traffic from different countries will be billed at different rates, based on the amount of data transferred from the CDN to the clients (browsers).

As shown in fig.1, the CDN is connect to the Function App, meaning that the CDN will source the static assets from the Function App. But the Function App in turn is connected to a storage account. Technically, all of these can be services from any of the 3 major cloud providers (Azure, AWS, GCP). It doesn’t make sense, though, to create individual services in multiple clouds. You would be charged more for inter-data center data transfer. So it is best to co-locate all of these, except of course, the CDN, which is always global, regardless of whose CDN service you end up using.

The connection between the CDN and the Function App is pretty simple, as it is just a matter of specifying the origin settings for the CDN. The connection between the Function App and the Storage Account requires a little bit more than just specifying the URL. We have to detect the incoming request at the Function and proxy it to the storage account, to let the storage account serve the static asset. Essentially, the Function App serves as a reverse-proxy here for some URL patterns, and for others, as a service that may or may not return a response, i.e., if there is an actual function that can handle the request.

Bonus! Let’s talk about automation

Let’s introduce a CI/CD pipeline into the mix. Azure has a really good all-in-one Ops platform called Azure DevOps, previously known as Visual Studio Team Services or VSTS, and even before that, Visual Studio Online. Anyway, the point of the platform is like Bitbucket or GitHub, where you have everything in one place. CI/CD pipeline integrations, release management, project planning (Kanban as well as sprint-based, whichever you are into), private/public repos, wikis, and also a private feed for your Nuget (.Net packages), npm or maven packages too!

Don’t take my word for it, though. After all, I am just some random programmer on the internet. People say a lot of things. But seriously, you should check it out.

Static websites architecture with Functions-Page-2

Here’s the screenshot of the pipelines page showing you the CI and PROD build pipelines for Net Your Problem.

Screenshot_2018-10-09 Builds - Pipelines

Here’s the CI/CD pipeline in Azure DevOps.

The pipeline is simple. Run npm ci –> npm install –> npm run build –> upload to Az Storage –> store artifacts. That’s it. I have a trigger for this pipeline, which would kick-off this build every time a branch is updated through a merge.

Admittedly, all of this may look like overkill. Trust me, it is not. I spend about a minute to run the build and then to upload the files to the Azure Storage. Then, sometimes, I have to purge the CDN cache, because, well, it works too well sometimes :). Overall, I could spend anywhere between 1-10 mins, and on average ~5 mins, deploying some changes. Now, repeat this several times as I am actively developing something or want to see how things look in Dev, or I want to show something to my ahem client (my girlfriend), the time investment adds-up really quickly. This setup allows me to focus just on the coding part and push up my changes for a quick review on the dev site, before I create a release for the PROD and have approved changes go to the live site immediately. All of this is a pleasant experience for me. To my girlfriend, it makes no difference, and that’s a good thing. She just sees the dev site and the live site. That’s it.

You see, the delays in development, often affects our customers. When I have a pipeline, that works well, my customer doesn’t get affected by it. They just see what they need to see. To them, in the end, it matters if they are able to see what they want and if it works. If the process gets in their way, they simply won’t get it. If I could use the overused automobile world for an analogy. This experience would be akin to taking our car to a shop for an oil change. At the end of it, we just want to drive our car out of the shop with a new oil filter, and fresh oil. We don’t care and most of us don’t want to know how they were able to do an oil change without an appointment. On the other hand, if the oil change took too long, then we want an explanation and all of the shop’s fancy equipment and ISO certifications wouldn’t save them from our negative experience.