Virtual machines cost money when they’re powered on. Most servers obviously need to be on 24 hours a day. Others, like development machines, only have to be on when you’re using them. And if you forget to turn them off, they’ll empty out your Azure credits (or your credit card) before you know it.
Today, I’ll show you how to set an Auto-shutdown time to turn a VM off if you forget, as well as have Azure notify you on Slack 30 minutes ahead of time, so you have the option to postpone or cancel the shutdown.
I wrote this quick-and-dirty script to let me know if I happen to forget to turn off a P15 instance, or if I configure a service with a super-expensive performance tier without realizing. Maxing out your free Azure credits may be depressing enough, but emptying your credit card could really put you in the hurt locker.
So, here’s a Powershell script that warns me before any of this happens. It uses the Azure Consumption API to check how much money we’ve racked up on a subscription so far, and if any single instance exceeds, say, 50% of that total cost, it sends a notification to a Slack channel.
If you haven’t heard of Slack, it’s a wonderful team messaging platform. At first glance, it looks a bit like a private Twitter where you can set up “channels” to have conversations with colleagues. But the great thing with Slack is its flexible API and all the marvelous ways in which you can extend its functionality. You can send rich text messages with status updates from your production servers or you can interface with popular web services like Trello, right there in the chat window!
So as a way to kick start an effort at learning node.js and re-discover web development (which I haven’t really done in about 15 years now), I set out to build a Slack API. Here’s what I learned.