Function Run

pkg/routine/routine.go:88–123

Run runs the given function in a new background context. Panics thrown in the function are logged and sent to sentry. The routines context is canceled if the program receives a shutdown signal (SIGINT, SIGTERM), if the returned CancelFunc is called, or if the routine returned.

(ctx context.Context, routine func(context.Context))

// canceled if the program receives a shutdown signal (SIGINT, SIGTERM), if the
// returned CancelFunc is called, or if the routine returned.
func Run(ctx context.Context, routine func(context.Context)) (cancel context.CancelFunc) {
	ctx = context.WithoutCancel(ctx)

	// add routine number to context and logger
	num := atomic.AddInt64(&ctr, 1)

	ctx = context.WithValue(ctx, ctxNumKey{}, num)
	logger := log.Ctx(ctx).With().Int64("routine", num).Logger()
	ctx = logger.WithContext(ctx)
	// get cancel function
	ctx, cancel = context.WithCancel(ctx)

	// register context to be cancelled when the program is shut down
	contextsMx.Lock()
	contexts[num] = cancel
	contextsMx.Unlock()
	// deregister the above if context is done
	go func() {
		<-ctx.Done()
		// In case of a shutdown, this will block forever. But it doesn't hurt,
		// because the program is about to exit anyway.
		contextsMx.Lock()
		defer contextsMx.Unlock()
		delete(contexts, num)
	}()
	go func() {
		defer errors.HandleWithCtx(ctx, fmt.Sprintf("routine %d", num)) // handle panics
		defer cancel()

		span := sentry.StartSpan(ctx, "function", sentry.WithDescription(fmt.Sprintf("routine %d", num)))
		defer span.Finish()

		routine(span.Context())
	}()
	return
}

type ctxNumKey struct{}