| I've been doing this a long time and seen a few different apps use config in database. There's different levels of config you're talking about here, but general app config should generally not go in a db. No-one ever changes the bloody things and it's just an extra thing to go wrong. If it only loads on startup, it achieves nothing over a bog standard config file. If it loads every request you've just incurred a 5% overhead on every call. And it ALWAYS ends up filled with crap that doesn't work anymore. Because unlike config files, no-one clear it up. Worse still is when people haven't made it injectable and then it means unit tests rely on a real database, or it blocks getting a proper CI/CD pipeline working. I end up having to pick the damn thing out of the app. Use a config file like everyone else that's probably built into the framework you're using. To be honest, most of the time I've seen it has been when people who clearly did not know their language/framework who wrote the app. I'm not saying it's you, but that's been my honest experience of config in the db, it's generally been a serious code smell that the whole app will be bad. |
In my experience, feature flagging is more application-level than system-level. What I mean by that is, feature flagging is for stuff like: roll this feature out to 10% of users, or to users in North America, or to users who have opted into beta features; enable this feature and report conversion metrics (aka A/B testing); enable this experimental speedup for 15 minutes so we can measure the performance increase. It's stuff that you want to change at runtime, through centralized tooling with e.g. auditing and alerting, without restarting all of your application servers. It's a bit different than config for like "what's the database host and user", stuff that you don't want to change after initialization (generally).
Regarding the article though, early on your deployment pipeline should be fast enough that updating a hardcoded JSON file and redeploying is just as easy as updating a feature flag, so I agree it's not something to invest in if you're still trying to get your first 1000 users.