Push-button deployments with Arduino
TL;DR: Thanks to an Arduino, an Arduino ethernet shield, some Arduino code, buttons from eBay, LEDs from Fry’s, and SmugMug’s deployment web app, we’ve created a push-button deployment process that looks like this:
When I first started working at SmugMug, we deployed infrequently by manually merging branches, tagging, double-checking, then running a bunch of commands (some via sudo and some not). It was an eleven step process that not all developers had access to. Developers were usually uneasy about pushing due to the complexity involved.
Eventually the process was consolidated into a shell script, which still had to be run via sudo on a designated server. More recently, the shell script was wrapped in a web app that made things much easier.
While the web app is pretty awesome and easy to use, I thought using a real physical button to deploy code would be even better:
Introducing the SmugMug Deployinator 5000!
Arduino and Ethernet Shield
The Deployinator 5000 consists of the following components:
- Arduino Starter Kit
- Arduino Ethernet Shield
- Green, red and yellow 5v LEDs
- Lots of wires
- 2-button momentary switch with key lock station from eBay
- Protected toggle switch
- Used weather monitoring station enclosure from Weird Stuff
The setup is relatively simple. The toggle switch, key lock, and two momentary switches are all wired up in sequence so the Arduino sees them as one button. When all four are pressed, the Arduino makes an HTTP POST request to our deployment server, which then pushes any pending code live. While the Arduino is waiting for the deployment to finish, it blinks the yellow LED. When the push is deployed, the green LED lights up. If something goes horribly wrong, the red LED strikes fear into the deployer’s heart.
It wasn’t too hard to wire up the Arduino, the buttons, and the LEDs, even for someone with no electronics experience (although I had a bit of help from other SmugMug employees with more experience). The fun and challenging part was finding an enclosure and mounting all the pieces inside it. Trips to Weird Stuff and Home Depot solved that problem easily!
After gutting the enclosure, I superglued the Arduino holder to the inside and drilled holes into the backing plate to mount the buttons with machine screws. I then reattached a few wires and circuitry for dramatic effect.
Long-term ideas for the Deployinator include adding larger lights, a disco ball, and playing music when a push occurs. PowerSwitch Tails would allow the Arduino to control anything that runs on 120V power.
Deploying code doesn’t have to be boring!
– Ryan Doherty, SmugMug DevOps