example cache library

cache_library.go

type ObjectCache {}

func (r *ObjectCache) Cached(ctx context.Context, key string, callback func() (interface{}, error), storeIntoPtr interface{}) error {
	// Check cache for object, if it exists, get it from cache, otherwise call callback, store to cache, and put result
	// into storeIntoPtr pointer
}

func (app * Application) UserCode(ctx context.Context) (*UserProfile, error) {
	var ret *UserProfile
	err := app.Cache.Cached(ctx, "user:" + userID, func() (interface{}, error) {
		// This is only called if the object isn't in the cache
		return app.BackingStore.GetUser(ctx, userID)
	}, &ret)
	return ret, err
}