Haskell Application Monad

We want to get productive in Haskell very quickly. Most non-trivial applications will have configuration, connections to the outside world, can hit exceptional conditions, and benefit from having their operations logged. If your application has sensible logs at both high an low levels of detail, your devops team will thank you and your life of debugging a production application will be a happier one.

I want to get all of these things at once, and so it would be nice to provide a nearly boilerplate application stack that provides them all. I define the “application stack” as a group of attributes that contain the context and all of the common behaviors for an application. In Haskell, you do that with a monad stack, though work on extensible effects shows a great deal of promise and has been used to great effect in Purescript.

Configuring your Haskell application

One way or another, you are going to need to configure your Haskell application, and for that you have three major ways of doing it. I recommend choosing one and sticking to it. You can choose multiple ones, but it is important that you minimize one of them in order to keep yourself out of the mind-numbing tedium of consistently combining multiple input parameter sets and their overrides.

Your options tend to be…

Resistance

For the next ten days, my resistance against fascism is to sit with an enby who has just undergone surgery. The kind of person and surgery that self-proclaimed “decent folk” believe is an abomination worthy of death.

If you are one of them, fuck off.

A Quiet Walk, Interrupted

Yesterday, my friend and I were out walking along the Delaware Canal Towpath in Morissville, Pennsylvania, having a lovely day. Part of the canal is still frozen, and we made a hobby of seeing if we could break the ice using whatever rocks we had to hand. The sound of an ice sheet fracturing is really unique. Not precisely like glass shattering, because the fracture and stresses race down the ice sheet, even if the break only happens in a small area. I lost count of the number of significant rocks that I hurled into the ice that simply got embedded.

16 Years

Welcome to 2017!

In a few days I move away from Austin, likely never to return. I grew up in Round Rock. I went away for a few years, and then I returned here to begin my career and my adult life right during the dot-com crash. I’m actually a lot older than I look. Many people upon meeting me seem to assume that I’m 27 or so, when in fact I turned 38 late this year. “Wait, how old are you?”

Nix Development Environments

nix-shell, the command that creates a subshell after evaluating any nix expression, has a lot of uses. I found it very useful in my devops work when I had multiple environments to administer, but had to use different tools for each. The shell provides excellent help in isolating my required tools to the environments involved.

A trick, though, lay in learning how to acquire those tools when the tools were not available in the nixos channel. I figured it out, and so here is the example for one of the environments I was administering. Note that I include both Linux and Darwin builds, because I wanted to offer the nix environment to my replacement at the company.