hashicorp/nomad · error

Error formatting the data: %w

Error message

Error formatting the data: %w

What it means

After Format successfully resolves a DataFormat, it applies f.TransformData(data) to render the output. If rendering fails (bad Go template syntax, unknown template function, or JSON marshaling problems), the underlying error is wrapped as "Error formatting the data: %w".

Source

Thrown at command/data_format.go:97

	var format string
	if json && len(template) > 0 {
		return "", fmt.Errorf("Both json and template formatting are not allowed")
	} else if json {
		format = "json"
	} else if len(template) > 0 {
		format = "template"
	} else {
		return "", fmt.Errorf("no formatting option given")
	}

	f, err := DataFormat(format, template)
	if err != nil {
		return "", err
	}

	out, err := f.TransformData(data)
	if err != nil {
		return "", fmt.Errorf("Error formatting the data: %w", err)
	}

	return out, nil
}

func makeFuncMap() template.FuncMap {
	fm := template.FuncMap{}

	// Add the Sprig functions to the funcmap. These functions are decorated
	// with `sprig_` to match how they are treated in consul-template
	for k, v := range sprig.FuncMap() {
		target := "sprig_" + k
		fm[target] = v
	}

	return fm
}

View on GitHub (pinned to 482b49bf1a)

Solutions

1. Read the wrapped cause after the colon and fix the template syntax/function name accordingly
2. Validate the template with `nomad job inspect -t '<template>'` or `go template` parse locally before scripting against it
3. Switch to -json output and post-process with jq if the template keeps failing

Example fix

// before
nomad status -t '{{.JobIDX}}' <id>
// after
nomad status -t '{{ range . }}{{ .ID }}{{ end }}' <id>

// parse the template first in tests:
if _, err := template.New("t").Funcs(makeFuncMap()).Parse(tmpl); err != nil {
    return err
}

out, err := Format(data, json, tmpl)
if err != nil {
    var wf interface{ Unwrap() error }
    if errors.As(err, &target) { /* inspect wrapped cause */ }
    return fmt.Errorf("check -template syntax: %w", err)
}

When it happens

Trigger: Calling Format with template=true path where the -template string is invalid Go template syntax, references an undefined function, or the data cannot be transformed by the json/templating backend.

Common situations: Users hand-write go template strings with typos (e.g. {{.Job.IDX}}), use a sprig/template function name that isn't in makeFuncMap, or pipe output where the data shape differs from what the template expects.

Related errors

• not a terminal
• both -n and -c set
• Allocation %q is running the following tasks: * %s Please
• Region not found
• evaluation ID or filter flag required

AI-assisted analysis of hashicorp/nomad@482b49bf1a (2026-09-04). Data as JSON: /api/errors/aafd21ba57f7a488. Report an issue: GitHub.