Rising sun

Recently my interest in the Go programming language changed from dormant back to active. Being a .NET developer by day and frankly getting new feature fatigue. I was drawn to a simpler world. I studied Go in the past using e.g. exercism and watching every Rob Pike youtube video I could find. I brushed up on what I learned before and found that with the introduction of Go modules, life improved quite a bit. I was lucky to find the fantastic Just for func youtube channel, that really helped me to learn more about the practicalities of writing Go code.

The likes

I started by writing a really small stub implementation of a SOAP service at work. This was really easy given the excellent support for HTTP in the net/http package and Fiddler. My routine was,

• detect what calls to the service were being made,
• grab the response body using Fiddler,
• reformat it,
• paste it into the Go code,
• check if some part of the response needed to be parameterized,
• if so add some %s directives and use fmt.Fprintf instead of fmt.Printf to write to the response.

I especially appreciated that the standard library fills the HTTP Content-Type header correctly based on the content written to the writer.

Inception

With this positive experience behind me, I was trying to find a next project to work on. Recently I was experimenting with moving my work tracking/todo list management setup from Emacs Org-Mode to Taskwarrior. What I was missing was the ability to make brief notes about activities that were not planned or part of my todo list but that I do anyway. Think of things like helping a coworker with some problem they are having, or e.g. responding to an email from a customer. I’m aware of the log command of taskwarrior but I felt these smallish items should not pollute my task list. I tried taskbook to fill in this gap but wasn’t happy with it. So what else to do but to write something really simple myself. This marked the birth of sun.

Design

One key feature I wanted to implement was that notes would only be shown of the recent past. Next to that sun should be fast and perform in constant time. Another restriction I put on myself was to only use the Go standard library. Once I looked at the different options in the encoding package. I decided to use encoding/gob and encoding/binary in conjunction to be able to read the data file starting at the end. The file layout is explained in the picture below, courtesy of the excellent svgbob application.

This layout has two main advantages it is simple to write when appending a new entry to the file and it can be read in reverse from the end of the file in a straightforward manner.

Implementation

The implementation of the reading and writing of the data was done quickly. The rest of the application was a lot of getting used to how error handling is done in Go. Having played with languages such as Rust, the Go usage of errors is still something I struggle with. Being a fan of small functions I found it hard to choose the correct function size in Go without duplicating the error handling on multiple levels.

Following through

My GitHub account currently counts a large number of dreams/ideas and someday maybes. What made this project different was that I wanted the functionality for my daily work and it was small and simple enough that I could implement it in a limited amount of time. I was also very pleased to have found Asciidoctor which allowed me to have a README file that is presented on GitHub nicely, which can be transformed into a simple website easily. Asciidoctor also supports conditionals, which makes it possible to include parts of the document only when processed by GitHub for instance. A few clicks on Netlify and a deployment one-liner and Bob’s your uncle. The fact that Go makes cross-compilation so easy and some shell scripting made it easy to publish a release to GitHub semi-automatically. Since I don’t expect to add any features to sun trying to fully automate the release process seems overkill.

In conclusion

I had some real fun implementing sun and learning a lot about Go in the process. Have a look at the code on GitHub if your interested. If you have any suggestions about possible improvements for the code please let me know, I’m eager to learn. I hope this very small utility provides some value to others, 🙏.