func populateInstalledCache()

in config/package_resource.go [343:398]
42 lines of code
12 McCabe index (conditional complexity)

func populateInstalledCache(ctx context.Context, mp ManagedPackage) error {
	var cache *packageCache
	var refreshFunc func(context.Context) ([]*packages.PkgInfo, error)
	var err error
	switch {
	case mp.Apt != nil:
		cache = aptInstalled
		refreshFunc = packages.InstalledDebPackages

	case mp.Deb != nil:
		cache = debInstalled
		refreshFunc = packages.InstalledDebPackages

	case mp.GooGet != nil:
		cache = gooInstalled
		refreshFunc = packages.InstalledGooGetPackages

	case mp.MSI != nil:
		// We just query per each MSI.
		return nil

	// TODO: implement yum functions
	case mp.Yum != nil:
		cache = yumInstalled
		refreshFunc = packages.InstalledRPMPackages

	// TODO: implement zypper functions
	case mp.Zypper != nil:
		cache = zypperInstalled
		refreshFunc = packages.InstalledRPMPackages

	case mp.RPM != nil:
		cache = rpmInstalled
		refreshFunc = packages.InstalledRPMPackages
	default:
		return fmt.Errorf("unknown or unpopulated ManagedPackage package type: %+v", mp)
	}

	// Cache already populated within the last 3 min.
	if cache.cache != nil && cache.refreshed.After(time.Now().Add(-3*time.Minute)) {
		return nil
	}

	pis, err := refreshFunc(ctx)
	if err != nil {
		return err
	}

	cache.cache = map[string]struct{}{}
	for _, pkg := range pis {
		cache.cache[pkg.Name] = struct{}{}
	}
	cache.refreshed = time.Now()

	return nil
}