AWS CloudWatch Alarms Too Noisy Due To Ignoring Missing Data in Averages

I want to know when our app starts getting slower so I sat up an alarm on the Latency metric of our ELB. According to the AWS Console, “This alarm will trigger when the blue line [average latency over the period of 15 min] goes above the red line [2 sec] for a duration of

Git pre-commit hook that fails if “it.only” used (Jest/Jasmine)

One of the annoying things with Jest is that while it enables you to run only a single test by using it.only, it does not report this in any noticeable way. Thus you can end up in the same situation as we did, not running many tests without knowing it. (Oh yeah, if we only

There will be failures – On systems that live through difficulties instead of turning them into a catastrophy

Our systems always depend on other systems and services and thus may and will be subject to failures – network glitches, dropped connections, load spikes, deadlocks, slow or crashed subsystems. We will explore how to create robust systems that can sustain blows from its users, interconnecting networks, and supposedly allied systems yet carry on as

A Usable Node.js REPL for Emacs

Being used to the excellent REPL in Clojure(Script), I was surprised to find out that Node.js REPL is somewhat weak and that its support in Emacs is not actively maintained. I anyway managed to get a usable REPL with these three components: The Emacs nodejs-repl package (nearly 2 years old) J. David Smith’s nodejs-repl-eval.el to