When a project's config inherits yours
Two configs for one tool, the user's and the project's, and no rule anywhere about which one wins. Twenty minutes to make one a layer of the other and keep a straight answer about where every value came from.
Tags
10 pages
Config
A format per module, not a fatter config core
Viper reads a dozen extensions. Mine reads one, and the other formats live somewhere else entirely. Here's what that bought, measured rather than asserted.
YAML has comments for a reason
yamldoc is the editing half of YAML for Go: change one key and every byte you did not touch comes back exactly as it went in, comments included. It now has an engine of its own, and the numbers to show why.
The writer I added, and the Viper I deleted by accident
I set out to add a config writer and keep Viper. I ended up keeping the writer and deleting Viper, and I didn't notice until it was already gone.
Layering config without losing where a value came from
Four places a config value can come from, and the only question that matters at the wrong end of an incident: which one won, and why. Twenty minutes, one module, no services.
Config is a border, not a chain
I built a boundary so I wouldn't have to move my config package. Then I moved it anyway, and the boundary is the only reason that didn't hurt.
My blog was shipping 1.2 MB banners
A post hit Hacker News and the analytics showed pages far heavier than a static site should be. The cover images were the payload.
Building a CLI with go-tool-base, part 2: configuration your tool can trust
Configuration for a Go CLI: precedence of flags over env over files, per-command embedded defaults, layered config merging and a strict mode.
Reloading config without a restart
Hot-reloading configuration: watch the file, re-read it, swap it in atomically and notify observers, without restarting a long-running service.
The config key that quietly did nothing
Config loaders ignore keys they do not recognise, so a typo runs on the old value. Deriving a validation schema from struct tags to catch it.
