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2024

Rust inspired Async Lock for C

Venturing back into C# for the first time in a long time. I'm only 5 minutes in and already felt compelled to create a new utility class.

Essentially I'm adding an ASP.NET Web API to a daemon process, which requires that the REST API can get exclusive access to some daemon in-memory state. Since I'm building everything around async/await, I went looking for the async equivalent of the traditional lock, only to not find one. From what I could gather, the recommendation is to build one around SemaphoreSlim. After using that explicitly, I was really uncomfortable with having to make sure that I a) released the semaphore and b) did it in a try/finally.

Mastodon Integration

Well, damn it. Here I am procrastinating on my archviz project with a server side project. I am an infrastructure engineer at heart, so anything server related will always pull at me harder than any other project. So right after writing the Future Work section in my last post, I started looking more closely at Daniel's approach to using mastodon for comments. The part that scratched my server-side geek itch was his chicken-egg problem forcing the workflow:

  1. create post
  2. create toot
  3. update post with toot id

I just want to publish my post, have a matching toot automatically be generated and have the original post be able to discover the corresponding toot_id. I want to keep my blog static and don't really want to add this into the build pipeline, so what I need is a web service that will lazy publish the toot and return the toot_id for a given URL.

Blogging with mkdocs

claassen.net was converted from static html and a wordpress site behind nginx on an EC2 instance to a static site generated by mkdocs hosted on S3.

The motivation

For the last ~10 years, I hosted everything on a single EC2 instance behind an ElasticIP. A couple of wordpress sites, some static sites, a couple of node apps, all through nginx. Deploy was git checkouts and some shell scripting. After having my server taken over once because of a wordpress vulnerability, I now ran all my wordpress with read-only files, so that felt decent. Just had to make them read/write for version and plugin updates. Mind you all this is very low traffic hobby sites.

But I really wanted to get to immutable deploys. Run these sites as separate docker containers I could more easily test locally and deploy was a replace. I converted one WP site to docker and figured out how to run it with ECS. Then last month I set out to decommission the EC2 and convert everything left.

My WP deploys were using the default WP container as a base, but claassen.net was structured with the blog as a sub-directory and a bunch of static site elsewhere. I considered reconfiguring the container to serve the existing hierarchy through its nginx, but in the 10 years of not posting, my tastes for authoring had moved distinctly from WYSIWYG to markdown and if I was going to get back to blogging, I wanted to go static. I briefly considered jekyll, but had been using MkDocs at work and really liked it, plus I am far more fluent in python than ruby. Some brief googling later, I found Material for MkDocs which comes out of the box with blogging support and with LoneKorean's WordPress Export to Markdown I was well on my way.

Deploying many sites in ECS using one ALB

My current go-to deployment strategy is AWS Elastic Container Service (ECS) using Fargate behind an Application Load Balancer (ALB). Each site is its own stateless docker container persisting dynamic data in RDS and/or S3. When I make a change, I build the new container, push it to ECR, create a new task revision and ECS deploys the site for me.

I've now set this up a couple of times and each time I struggle to recollect all the steps along the way, so it's high time I write it down so that I can look it up next time. And now that I understand this a bit better, I was also able to consolidate my infrastructure, since my original approach wasn't necessarily the most cost-efficient setup.

Aside from remembering/reverse engineering all the pieces needed, the part I always got stuck on was the apparent catch-22 of a load balancer wanting a target group, a target group wanting an IP, while the ECS Service wants to set up a load balancer before providing said IP.

ECS RunTask needs public IP to access env file

Learning how to use ECS tasks to run some cron jobs has been an opaque journey to say the least.

I knew my TaskDefinition was fine, because my server was running, but I wanted to use that same definition with a different container command and schedule its execution for housekeeping tasks.

I started with creating an EventBridge schedule, which seemed straight forward enough. But as soon as I created it I was puzzled that there didn't seem to be a way to trigger it for testing nor was there any kind of information on whether or not the last invocation had happened and succeeded.

Closing out a decade of silence

About a decade ago I stopped posting on this blog. It wasn't a conscious decision but between twitter and stackoverflow, my attention had just shifted. Twitter provided an easy way to post tech comments, seductive in its immediacy and the enforced brevity. So I, as many other tech bloggers, led ourselves to believe that the interactions on twitter were a sufficient replacement of blog posts. As a way to acquiesce those niggling objections to that former delusion, stackoverflow served the need for asking and answering questions in a more substantive way.

Over time, the gamification appeal of stackoverflow wore off after a while, and I became mostly a consumer with the occasional issue that I got stuck on. It's still my ends up my primary source of troubleshooting, but mostly because google drops me off there. These days getting really stuck usually has me tracking down a relevant Discord community instead.

And twitter I left at the start of the pandemic, primarily because they kept messing with the ordered timeline and even when nothing was injected, it had really turned into primarily doom scrolling.

But last year I decided to give mastodon a try and have found it to be very much like early twitter. Informative, casual, non-sensational. Just a nice place to get some tech news, trends and conversation from.

However, as I play around with whatever evening project I've got myself into now, I am reminded of why I started this blog in the first place. Namely, capturing my troubleshooting and discovery so that next time I ran into the same or similar I would recall having written it down, or at least have google lead me back here again. So that's what I hope to accomplish here over the next year and beyond.

As part of the move, I've dropped wordpress in favor of static generation using material for mkdocs. I'll talk about how I ended up with that in a future post, assuming this New Year's resolution holds.