Beyond the runbook – code and comments
Regardless of the amount of documentation an application has, the only true source to determine how an application works is its source code! The problem is that in today’s world of coding, even source code can be tricky to read at times. And while developers do add code comments, aka notes embedded in the code, remember they are not always correct or up to date. I tend to trust comments more than any other type of documentation though.
Quickly understanding source code
When analyzing source code, you’ve just been handed – and yes, you’ll have one of those outages at some time – there are a few tricks I’ve used over the years. But it always starts with finding the entry point where the code starts. This could be a function in the case of serverless functions, or simply the main() function inside main.c.
Most application frameworks these days also allow users to run code prior to the entry...