hashicorp/nomad · error

Job ID contains a null character

Error message

Job ID contains a null character

What it means

Job.Validate() rejects Job IDs containing a NUL byte ("\000"). NUL characters can corrupt string handling in downstream systems (logging, raft storage, C strings), so the validator explicitly disallows them. This check runs only after the empty-ID check passes.

Source

Thrown at nomad/structs/structs.go:4748

	nj.Periodic = j.Periodic.Copy()
	nj.Meta = maps.Clone(j.Meta)
	nj.ParameterizedJob = j.ParameterizedJob.Copy()
	return nj
}

// Validate is used to check a job for reasonable configuration
func (j *Job) Validate() error {
	var mErr multierror.Error

	if j.Region == "" && j.Multiregion == nil {
		mErr.Errors = append(mErr.Errors, errors.New("Missing job region"))
	}
	if j.ID == "" {
		mErr.Errors = append(mErr.Errors, errors.New("Missing job ID"))
	} else if strings.Contains(j.ID, " ") {
		mErr.Errors = append(mErr.Errors, errors.New("Job ID contains a space"))
	} else if strings.Contains(j.ID, "\000") {
		mErr.Errors = append(mErr.Errors, errors.New("Job ID contains a null character"))
	}
	if j.Name == "" {
		mErr.Errors = append(mErr.Errors, errors.New("Missing job name"))
	} else if strings.Contains(j.Name, "\000") {
		mErr.Errors = append(mErr.Errors, errors.New("Job Name contains a null character"))
	}

	if j.Namespace == "" {
		mErr.Errors = append(mErr.Errors, errors.New("Job must be in a namespace"))
	}
	switch j.Type {
	case JobTypeCore, JobTypeService, JobTypeBatch, JobTypeSystem, JobTypeSysBatch:
	case "":
		mErr.Errors = append(mErr.Errors, errors.New("Missing job type"))
	default:
		mErr.Errors = append(mErr.Errors, fmt.Errorf("Invalid job type: %q", j.Type))
	}
	if len(j.Datacenters) == 0 && !j.IsMultiregion() {

View on GitHub (pinned to 482b49bf1a)

Solutions

1. Strip NUL bytes from the ID before submission: strings.ReplaceAll(id, "\x00", "")
2. Validate input at the boundary with a regex like ^[^\x00]+$
3. Inspect the raw bytes of the ID (fmt.Sprintf("%q", id)) to find hidden control characters

Example fix

// before
job.ID = rawID
// after
job.ID = strings.ReplaceAll(rawID, "\x00", "")

if strings.Contains(j.ID, "\x00") {
    return fmt.Errorf("job ID contains a null character")
}

func isNulFree(s string) bool { return !strings.ContainsRune(s, '\x00') }

if err := job.Validate(); err != nil {
    if strings.Contains(err.Error(), "null character") {
        job.ID = strings.Map(func(r rune) rune { if r == 0 { return -1 }; return r }, job.ID)
    }
}

When it happens

Trigger: Submitting a job whose `id` contains an embedded null byte — typically via programmatic construction (j.ID = "job\x00suffix") or deserialized input containing NUL; direct calls to Job.Validate() in Go.

Common situations: Parsing binary or legacy encodings into strings that introduce NULs; string truncation bugs from C interop leaving trailing NULs; malicious or corrupted input from untrusted sources.

Understand the failure class

Background: "invalid id" errors: invalid identifier format — why libraries reject IDs before lookup, and how to fix them — this error's family across 37 libraries.

Related errors

• Job Name contains a null character
• Missing job ID
• Job ID contains a space
• Missing job name
• Job must be in a namespace

AI-assisted analysis of hashicorp/nomad@482b49bf1a (2026-09-04). Data as JSON: /api/errors/80c898227c4d0cc6. Report an issue: GitHub.