What causes "failed to read response body: %w" in OpenNHP/opennhp?

Retry GetEvidenceWithCCUrl — transient resets are common while AAA is warming up

failed to read response body

Error message

failed to read response body: %w

What it means

Raised by GetEvidenceWithCCUrl after a 200 response: io.ReadAll of the response body failed mid-transfer. The connection to the confidential-container evidence endpoint broke while streaming the body, so the raw evidence bytes could not be collected for compression and return to the WASM guest.

Solutions

Retry GetEvidenceWithCCUrl — transient resets are common while AAA is warming up
Check AAA container logs/OOM events at the failure timestamp
Increase the http.Client timeout and/or add a retry with backoff around the whole call

Example fix

// before
body, err := io.ReadAll(resp.Body)
// after
body, err := io.ReadAll(io.LimitReader(resp.Body, 1<<20))
if err != nil {
    return nil, retryOrWrap(err, "failed to read response body")
}

Defensive patterns

Strategy: retry

Try / catch

ev, err := engine.GetEvidenceWithCCUrl()
if err != nil {
    if strings.Contains(err.Error(), "failed to read response body") {
        time.Sleep(500*time.Millisecond)
        ev, err = engine.GetEvidenceWithCCUrl() // bounded retry
    }
}

Prevention

Monitor AAA container for OOM kills/crashes
Keep evidence payloads small and read with io.LimitReader
Use localhost directly (avoid proxies) for the AAA endpoint

When it happens

Trigger: AAA accepted the connection, sent 200, then closed early or the stream was interrupted mid-read (AAA crash while generating the TEE report, container OOM-kill, socket timeout).

Common situations: Attestation agent dying mid-request under memory pressure; TCP reset by a sidecar/proxy; large evidence payloads over an unstable link (rare for localhost, common through proxies).

Understand the failure class

Background: "failed to read file", EACCES, ENOENT and "could not read <path>" errors: when a program can't read a file from disk — this error's family across 49 libraries.

Related errors

AI-assisted analysis of OpenNHP/opennhp@6e04ca5ff0 (2026-09-07). Data as JSON: /api/errors/5821a39074412f8a. Report an issue: GitHub.

Appendix: source

Thrown at nhp/core/wasm/engine/host.go:53

}

func GetEvidenceWithCCUrl() ([]byte, error) {
	client := &http.Client{Timeout: 3 * time.Second}

	resp, err := client.Get(confidentialContainerEvidenceUrl)
	if err != nil {
		return nil, fmt.Errorf("http request failed: %w", err)
	}

	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("unexpected status code: %d", resp.StatusCode)
	}

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, fmt.Errorf("failed to read response body: %w", err)
	}

	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 {

View on GitHub (pinned to 6e04ca5ff0)