Thank you for quick response and suggestion, but I’m not good at speaking English.
So, It’s alright to take a time and share my email address but I’d like to communicate with text if you don’t mind.
To summarize,
- I want to use the feature flags for not only our colleagues but for our customers and force their flags on/off in our control. I often provide beta features and sometimes meat bugs affect our service health. So, I want them like circuit breaker to stop them as soon as possible without re-deploy.
- I want the feature flags to switch our services’ condition, on available or under maintenance. Our most service apis are hosted on Vercel using next.js, so we can use feature flags in edge middleware. To read flags, I want to redirect all requests to our maintenance page and return status code 503 from our api handlers.
It’s great that they can be without any modification of url or query parameters if it’s possible.
They may be difficult to be achieved by only session cookie and current feature flags overrides system. So, I first used edge config for our purpose and achieved them, but our service has many requests and cause many read of edge config though our edge config has only two flags and they seldom change. The result costs a few ten dollars per a day if no optimization (ex: our service keeps flag in session cookie and cache the object value during an request with feature flags for that though it’s still a little expensive) to read it and, I realized that edge config is not suitable for our purpose especially when the values seldom change. Alternative external low price storage is possible, but not optimal about latency.
Thus, I’m glad to achieve them with feature flags overrides or other features on edge runtime in vercel platform.