What causes "failed to read POST webhook response from %s" in bytebase/bytebase?

Retry the webhook POST — this is typically transient.

failed to read POST webhook response from %s

Error message

failed to read POST webhook response from %s

What it means

This error wraps a failure reading the full HTTP response body (io.ReadAll) after POSTing to the Discord webhook. It means the connection broke mid-read or a Body wrapper misbehaved — the response status is unknown.

Source

Thrown at backend/plugin/webhook/discord/discord.go:115

	}
	req, err := http.NewRequest("POST",
		context.URL, bytes.NewBuffer(body))
	if err != nil {
		return errors.Wrapf(err, "failed to construct webhook POST request to %s", context.URL)
	}

	req.Header.Set("Content-Type", "application/json")
	client := &http.Client{
		Timeout: webhook.Timeout,
	}
	resp, err := client.Do(req)
	if err != nil {
		return errors.Wrapf(err, "failed to POST webhook to %s", context.URL)
	}

	b, err := io.ReadAll(resp.Body)
	if err != nil {
		return errors.Wrapf(err, "failed to read POST webhook response from %s", context.URL)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusNoContent {
		return errors.Errorf("failed to POST webhook %s, status code: %d, response body: %s", context.URL, resp.StatusCode, b)
	}
	if resp.StatusCode == http.StatusNoContent || len(b) == 0 {
		return nil
	}

	webhookResponse := &WebhookResponse{}
	if err := json.Unmarshal(b, webhookResponse); err != nil {
		return errors.Wrapf(err, "malformed webhook response from %s", context.URL)
	}

	if webhookResponse.Code != 0 {
		return errors.Errorf("%s", webhookResponse.Message)
	}

View on GitHub (pinned to 1870550677)

Solutions

Retry the webhook POST — this is typically transient.
Check network stability/proxy health between the server and discord.com.
If persistent, inspect proxy/MTU issues that corrupt long responses.

Example fix

// before
b, err := io.ReadAll(resp.Body)
if err != nil {
  return errors.Wrapf(err, "failed to read POST webhook response from %s", context.URL)
}
// after
b, err := io.ReadAll(resp.Body)
if err != nil {
  return retryable(errors.Wrapf(err, "failed to read POST webhook response from %s", context.URL))
}

Defensive patterns

Strategy: retry

Try / catch

if err := discord.Post(ctx, whCtx); err != nil {
  if strings.Contains(err.Error(), "failed to read POST webhook response") {
    // transient read failure — safe to retry the whole POST (use idempotent content)
    return retryWithBackoff(func() error { return discord.Post(ctx, whCtx) })
  }
  return err
}

Prevention

Retry the POST on body-read failures — the message may or may not have been delivered.
Monitor proxy/network stability for long-lived HTTP responses.
Prefer stable network paths to discord.com (avoid flaky egress).

When it happens

Trigger: io.ReadAll(resp.Body) returns an error immediately after a successful client.Do — connection reset by peer, truncated response, or closed underlying connection.

Common situations: Discord or an intermediary proxy resets the connection mid-response; network interruption during read; very large/unexpected response with flaky link.

Understand the failure class

Background: 'Something went wrong' / 'Request failed (500)' / 'HTTP error! status: 404' — what failed HTTP requests actually mean and how to find the real cause — this error's family across 28 libraries.

Related errors

AI-assisted analysis of bytebase/bytebase@1870550677 (2026-09-06). Data as JSON: /api/errors/f34c50e4247552a9. Report an issue: GitHub.