Beer Me!

As a way to practice coding on my software development journey, I have embarked on experimenting with the Raspberry Pi platform. I am quite fond of beer, and I quite enjoy the art of brewing. In this process, the beer needs to be stored for weeks at a time, preferably in a location with a specific temperature range.

Raspberry Pi Zero and MCP9808

And it was thus that I thought of monitoring a spare closet with a Raspberry Pi Zero and an MCP9808 temperature sensor breakout board. The Pi is lightweight, requires minimal power, and the Zero has the bonus WiFi chip. So, I can stick it in the closet with a constant power supply, and basically leave it on for all eternity, if necessary. You can find out a little more about this project here. (Note: This is still very much a work in progress)

I finally got the code to place where I could indeed leave it on for days/weeks at a time. However, it was very fragile; basic errors (inability to communicate with a service to which it reports, or errors communicating with DarkSky, where I get local temperature data from, amongst other errors) would cause the monitor to crash and burn, and sometimes it would be a few days before I noticed. How can I fix this?

Crash And Burn, Baby!

Ultimately, the problem was bad coding on my part; ugly flow within a try/catch and lack of proper logging. Most of the time, I’d never see the error itself, so I had no idea what was taking down the monitor. I decided to set up a Slack bot to figure this out.

Slack Messaging To The Rescue

Start by going to the Slack API to create a new app 1; and hitting that green button “Create New App” 2. Enter an App Name, select an available workspace, then create that app!

There is a slew of options to setup and configure your app (bot); experiment to your hearts content! Don’t forget though, the ultimate goal is to have the script tell you when something fails, at the moment that it fails. If the failure results in my script burning, then I can quickly restart (as a stop-gap, at the very least). Under the “Features” section of your app, select “Incoming Webhooks”. Near the bottom of the panel that is displayed is a Webhook URL that you can copy. This is the URL you want to use when sending a message to Slack from within your app. There is even a sample request that you can try to make sure it indeed it works! Just make sure to create the webhook first, and link it to an existing channel (public or private).

In Closing …

This writeup is way too short to describe everything that had to be done in terms of setup. However, it is all fairly straightforward and shouldn’t cause too much heartache. For a real use case, check out my implementation that saved my python app from constantly crashing!

Happy Coding!

1: Assumes that you have a Slack account with access to a workspace.

2: You’ll also be required to agree to the Slack App Directory Agreement terms.