OpenNHP/opennhp · error

failed to get agent unique id

Error message

failed to get agent unique id: %v

What it means

Raised by GetEvidenceWithAgentUuid when the helper CalculateAgentUniqueId returns an error. The fallback evidence path builds a synthetic test-purpose evidence object keyed on the agent's unique id; without that id the evidence cannot be constructed, so the failure of the underlying id calculation is wrapped and propagated to the WASM guest.

Solutions

1. Inspect the wrapped inner error to see which identity source failed
2. Ensure the container/host exposes /etc/machine-id (or systemd-machine-id-setup) and a resolvable hostname
3. Fix file permissions on the identity files or configure an explicit agent id in the agent config

Example fix

// before
agentUniqueId, err := CalculateAgentUniqueId()
if err != nil {
    return nil, fmt.Errorf("failed to get agent unique id: %v", err)
}
// after
agentUniqueId, err := CalculateAgentUniqueId()
if err != nil {
    return nil, fmt.Errorf("failed to get agent unique id: %v (check /etc/machine-id and hostname)", err)
}

if _, err := os.Stat("/etc/machine-id"); err != nil {
    return errors.New("host identity unavailable: /etc/machine-id missing")
}

ev, err := engine.GetEvidence()
if err != nil {
    if strings.Contains(err.Error(), "failed to get agent unique id") {
        return fmt.Errorf("cannot build fallback evidence: %w", err)
    }
}

When it happens

Trigger: Calling GetEvidence (test/fallback path) when CalculateAgentUniqueId fails — typically because required machine/host identity sources (hostname, machine-id file, MAC address, or crypto/rand) are unavailable.

Common situations: Running the agent in a minimal container without /etc/machine-id or hostname configured; restricted filesystem permissions; crypto entropy source unavailable at boot.

Understand the failure class

Background: "is required", "must be set", "missing required field": configuration validation errors across open-source libraries — this error's family across 36 libraries.

Related errors

• failed to generate UUID:
• cluster : missing publicKeyBase64
• cluster ( ): no instances configured
• cluster ( )
• no private key configured; check etc/config.toml

AI-assisted analysis of OpenNHP/opennhp@6e04ca5ff0 (2026-09-07). Data as JSON: /api/errors/07cebfdb63542ad4. Report an issue: GitHub.

Appendix: source

Thrown at nhp/core/wasm/engine/host.go:72

	}

	var buf bytes.Buffer
	w := zlib.NewWriter(&buf)
	_, err = w.Write(body)
	w.Close()
	if err != nil {
		return nil, fmt.Errorf("failed to compress response body: %w", err)
	}

	compressedBody := buf.Bytes()

	return compressedBody, nil
}

func GetEvidenceWithAgentUuid() ([]byte, error) {
	agentUniqueId, err := CalculateAgentUniqueId()
	if err != nil {
		return nil, fmt.Errorf("failed to get agent unique id: %v", err)
	}

	evidence := map[string]any{
		"test_purpose":  "this evidence is for testing purposes only",
		"measure":       agentUniqueId,
		"serial_number": agentUniqueId,
	}

	evidenceBytes, err := json.Marshal(evidence)
	if err != nil {
		return nil, fmt.Errorf("failed to marshal evidence: %v", err)
	}

	var buf bytes.Buffer
	w := zlib.NewWriter(&buf)
	_, err = w.Write(evidenceBytes)
	w.Close()
	if err != nil {

View on GitHub (pinned to 6e04ca5ff0)