nats-io/nats-server · error

invalid pid: %s

Error message

invalid pid: %s

What it means

ProcessSignal validates the optional pid argument (after stripping a trailing '*' glob marker) and strconv failed to parse it as an integer PID. The offending string is echoed; it fires before any signal is sent, purely from CLI argument validation in nats-server --signal.

Source

Thrown at server/signal.go:105

// ProcessSignal sends the given signal command to the given process. If pidStr
// is empty, this will send the signal to the single running instance of
// nats-server. If multiple instances are running, pidStr can be a globular
// expression ending with '*'. This returns an error if the given process is
// not running or the command is invalid.
func ProcessSignal(command Command, pidExpr string) error {
	var (
		err    error
		errStr string
		pids   = make([]int, 1)
		pidStr = strings.TrimSuffix(pidExpr, "*")
		isGlob = strings.HasSuffix(pidExpr, "*")
	)

	// Validate input if given
	if pidStr != "" {
		if pids[0], err = strconv.Atoi(pidStr); err != nil {
			return fmt.Errorf("invalid pid: %s", pidStr)
		}
	}
	// Gather all PIDs unless the input is specific
	if pidStr == "" || isGlob {
		if pids, err = resolvePids(); err != nil {
			return err
		}
	}
	// Multiple instances are running and the input is not an expression
	if len(pids) > 1 && !isGlob {
		errStr = fmt.Sprintf("multiple %s processes running:", processName)
		for _, p := range pids {
			errStr += fmt.Sprintf("\n%d", p)
		}
		return errors.New(errStr)
	}
	// No instances are running
	if len(pids) == 0 {

View on GitHub (pinned to 3a66a489d2)

Solutions

1. Pass a valid numeric pid, e.g. nats-server --signal <pid>:m
2. Drop the pid to signal the single running instance
3. Use a glob like '123*' only with digits before the '*'

When it happens

Trigger: Thrown at server/signal.go:105 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of nats-io/nats-server@3a66a489d2 (2026-09-02). Data as JSON: /api/errors/eddb5f928a99883a. Report an issue: GitHub.