package controller import ( "context" "golang.org/x/sync/errgroup" ) type Starter interface { Sync(ctx context.Context) error Start(ctx context.Context, threadiness int) error } func SyncThenStart(ctx context.Context, threadiness int, starters ...Starter) error { if err := Sync(ctx, starters...); err != nil { return err } return Start(ctx, threadiness, starters...) } func Sync(ctx context.Context, starters ...Starter) error { eg, _ := errgroup.WithContext(ctx) for _, starter := range starters { func(starter Starter) { eg.Go(func() error { return starter.Sync(ctx) }) }(starter) } return eg.Wait() } func Start(ctx context.Context, threadiness int, starters ...Starter) error { for _, starter := range starters { if err := starter.Start(ctx, threadiness); err != nil { return err } } return nil }