hashicorp/nomad · error

failed to hcl parse the config: %v

Error message

failed to hcl parse the config: %v

What it means

Launcher config error in hclConfigToAny: the plugin config blob sent to the external device plugin is not parseable HCL, so it cannot be decoded into the map handed to the plugin's SetConfig. The offending config is the plugin config from the jobspec/client.

Source

Thrown at plugins/shared/cmd/launcher/command/device.go:227

		ApiVersion:   apiVersion,
	}

	if err := c.dev.SetConfig(req); err != nil {
		return err
	}

	return nil
}

func hclConfigToAny(config []byte) (any, error) {
	if len(config) == 0 {
		return map[string]any{}, nil
	}

	// Parse as we do in the jobspec parser
	root, err := hcl.Parse(string(config))
	if err != nil {
		return nil, fmt.Errorf("failed to hcl parse the config: %v", err)
	}

	// Top-level item should be a list
	list, ok := root.Node.(*ast.ObjectList)
	if !ok {
		return nil, fmt.Errorf("root should be an object")
	}

	var m map[string]any
	if err := hcl.DecodeObject(&m, list.Items[0]); err != nil {
		return nil, fmt.Errorf("failed to decode object: %v", err)
	}

	return m["config"], nil
}

func (c *Device) startRepl() error {
	// Start the output goroutine

View on GitHub (pinned to 482b49bf1a)

Solutions

1. Fix the HCL syntax in the device config at the line/column reported by the wrapped error.
2. Validate the config with an HCL linter/parser before deploying.
3. Ensure the config is HCL (not JSON/YAML) and free of non-ASCII/smart quotes.
4. Check file encoding (strip BOM) and encoding round-trips.

Example fix

// before
config "mock" {}
  foo = "bar"
// after
config "mock" {
  foo = "bar"
}

// Pre-validate config parses as HCL before handing it to the device
if _, err := hcl.Parse(string(config)); err != nil {
	return fmt.Errorf("invalid device config HCL: %w", err)
}

if err := setConfigErr; err != nil && strings.Contains(err.Error(), "failed to hcl parse") {
	// surface the hcl position info from the wrapped error to the operator
}

When it happens

Trigger: setConfig receives device config bytes that fail hcl.Parse: missing braces, bad syntax, stray characters, or non-HCL content.

Common situations: Typos in device plugin configuration files; JSON/YAML pasted where HCL is expected; unclosed blocks or quotes; editor artifacts (smart quotes, BOM) in config files.

Related errors

• failed to parse HCL file %s: %w
• error parsing: root should be an object
• cannot check HCL keys of type %T
• root should be an object
• failed to decode object: %v

AI-assisted analysis of hashicorp/nomad@482b49bf1a (2026-09-04). Data as JSON: /api/errors/6641f9a55d89e200. Report an issue: GitHub.