Track your weight with a CGI script and Go
Programming Snapshot – Go CGI Scripting

© Lead Image © mathias the dread, photocase.com
Mike Schilli steps on the scale every week and records his weight fluctuations as a time series. To help monitor his progress, he writes a CGI script in Go that stores the data and draws visually appealing charts.
Capturing datapoints, adding them to a time series, and showing values over time graphically is usually the domain of tools like Prometheus. The tool retrieves the status of monitored systems at regular intervals and stores the data as a time series. If outliers occur, the messenger of the gods alerts its human to the fact. Viewing tools such as Grafana display the collected time series in dashboards spread over the last week or year as graphs, if so desired, so that even senior managers can see at a glance what's going on in the trenches.
However, my el cheapo web host won't let me install arbitrary software packages for this purpose on my rented virtual server. Plus, maintaining such complicated products with their continuous updates would be too time consuming for me, anyway. However, there is a '90s-style CGI interface on the web server. How hard could it be to write a CGI program in Go that receives measured values via HTTPS like an API, formats the time series generated from them into an attractive chart, and sends the results back to the browser in PNG format? Let's find out.
Figure 1 shows the graph of a time series that outputs my weight in kilograms over the past few years (possibly embellished for this article) as a chart in the browser after pointing it to the URL on the server. The same CGI script also accepts new incoming data. For example, if my scale shows 82.5 kilograms one day, calling
[...]
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.

News
-
Linux Kernel 6.17 Drops bcachefs
After a clash over some late fixes and disagreements between bcachefs's lead developer and Linus Torvalds, bachefs is out.
-
ONLYOFFICE v9 Embraces AI
Like nearly all office suites on the market (except LibreOffice), ONLYOFFICE has decided to go the AI route.
-
Two Local Privilege Escalation Flaws Discovered in Linux
Qualys researchers have discovered two local privilege escalation vulnerabilities that allow hackers to gain root privileges on major Linux distributions.
-
New TUXEDO InfinityBook Pro Powered by AMD Ryzen AI 300
The TUXEDO InfinityBook Pro 14 Gen10 offers serious power that is ready for your business, development, or entertainment needs.
-
Danish Ministry of Digital Affairs Transitions to Linux
Another major organization has decided to kick Microsoft Windows and Office to the curb in favor of Linux.
-
Linux Mint 20 Reaches EOL
With Linux Mint 20 at its end of life, the time has arrived to upgrade to Linux Mint 22.
-
TuxCare Announces Support for AlmaLinux 9.2
Thanks to TuxCare, AlmaLinux 9.2 (and soon version 9.6) now enjoys years of ongoing patching and compliance.
-
Go-Based Botnet Attacking IoT Devices
Using an SSH credential brute-force attack, the Go-based PumaBot is exploiting IoT devices everywhere.
-
Plasma 6.5 Promises Better Memory Optimization
With the stable Plasma 6.4 on the horizon, KDE has a few new tricks up its sleeve for Plasma 6.5.
-
KaOS 2025.05 Officially Qt5 Free
If you're a fan of independent Linux distributions, the team behind KaOS is proud to announce the latest iteration that includes kernel 6.14 and KDE's Plasma 6.3.5.