What causes "service %s start: %w" in gofiber/fiber?

Increase the startup deadline via ServicesStartupContextProvider.

service %s start: %w

Error message

service %s start: %w

What it means

Returned by startServices (services.go:105) when a service's Start(ctx) returns context.Canceled or context.DeadlineExceeded. Fiber wraps it so the offending service name (srv.String()) and the original sentinel are visible, and startServices returns immediately rather than continuing to later services.

Source

Thrown at services.go:105

	for idx, srv := range app.configured.Services {
		if srv == nil {
			return fmt.Errorf("fiber: service at index %d is nil", idx)
		}
		if err := ctx.Err(); err != nil {
			// Context is canceled, return an error the soonest possible, so that
			// the user can see the context cancellation error and act on it.
			return fmt.Errorf("context canceled while starting service %s: %w", srv.String(), err)
		}

		err := srv.Start(ctx)
		if err == nil {
			// mark the service as started
			app.state.setService(srv)
			continue
		}

		if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
			return fmt.Errorf("service %s start: %w", srv.String(), err)
		}

		errs = append(errs, fmt.Errorf("service %s start: %w", srv.String(), err))
	}
	return errors.Join(errs...)
}

// shutdownServices Handles the shutdown process of services for the current application.
// Iterates over all the started services in reverse order and tries to terminate them,
// returning an error if any error occurs.
func (app *App) shutdownServices(ctx context.Context) error {
	if app.state.ServicesLen() == 0 {
		return nil
	}

	var errs []error
	for key, srv := range app.state.Services() {
		if srv == nil {

View on GitHub (pinned to 9a4c7e57fe)

Solutions

Increase the startup deadline via ServicesStartupContextProvider.
Make Service.Start non-blocking: kick off background reconnect and return nil once ready enough.
Separate the shutdown signal from the startup context so boot is not prematurely canceled.
Use context.WithTimeout with a value sized to your slowest dependency's connect time.

Example fix

// before: Start blocks until deadline
func (s *RedisSvc) Start(ctx context.Context) error {
    return s.client.Ping(ctx).Err()
}

// after: bounded retry, return on readiness
func (s *RedisSvc) Start(ctx context.Context) error {
    return retry.Do(s.client.Ping(ctx).Err,
        retry.Context(ctx), retry.Attempts(5), retry.Delay(200*time.Millisecond))
}

Defensive patterns

Strategy: retry

Try / catch

if err := app.startServices(ctx); err != nil {
    if errors.Is(err, context.DeadlineExceeded) {
        // extend deadline and retry, or fail boot with diagnostics
    }
}

Prevention

Implement Service.Start to be fast or non-blocking.
Use retry-with-backoff inside Start for transient dependency failures.
Monitor boot duration and alert before the deadline.

When it happens

Trigger: A Service.Start implementation respects ctx and returns ctx.Err() (or an error wrapping context.Canceled/DeadlineExceeded) when the startup context is canceled. The errors.Is check at services.go:104 classifies it as a context failure and short-circuits the loop.

Common situations: Service that blocks on a slow external resource (DB, cache, message broker) under a startup deadline; container orchestrator sends SIGTERM mid-boot; tests with a tight context.WithCancel around app.New.

Related errors

AI-assisted analysis of gofiber/fiber@9a4c7e57fe (2026-08-04). Data as JSON: /data/errors/f58686f3225baccb.json. Report an issue: GitHub.