crowdsecurity/crowdsec · error

cannot read line in response

Error message

cannot read line in response: %w

What it means

readResponse reads the streaming newline-delimited JSON body line by line with a JSON decoder/reader. When a read fails for a reason other than EOF or context cancellation (connection reset, unexpected short read, I/O error), the error is wrapped with "cannot read line in response" and returned to doQueryRange.

Solutions

1. Check the wrapped inner error for the root cause (connection reset, unexpected EOF, timeout)
2. Reduce the `limit` in the DSN so responses complete faster and are less likely to be dropped
3. Check intermediate proxies/load balancers idle timeouts for long streaming responses
4. Ensure VictoriaLogs is stable and not restarting during queries

try {
  await runAcquisition()
} catch (e) {
  if (String(e).includes("cannot read line in response")) {
    log.warn("Stream dropped, restarting acquisition", e.message)
    scheduleRestart()
  } else { throw e }
}

When it happens

Trigger: The response body reader returns a non-EOF, non-canceled error mid-stream — e.g. the HTTP connection is reset by VictoriaLogs or a proxy while the acquisition is still reading.

Common situations: Large result sets taking long enough for an idle timeout/load balancer to kill the connection, VictoriaLogs restarting mid-query, proxy or keep-alive misconfiguration dropping long-lived streaming responses.

Related errors

• error while reading tail response
• error tailing logs
• querying range
• unable to read body
• api register ( )

AI-assisted analysis of crowdsecurity/crowdsec@909b515798 (2026-09-06). Data as JSON: /api/errors/474e714e8b601809. Report an issue: GitHub.

Appendix: source

Thrown at pkg/acquisition/modules/victorialogs/internal/vlclient/vl_client.go:210

		case <-ctx.Done():
			return n, latestTS, nil
		default:
		}

		b, err := br.ReadBytes('\n')
		if err != nil {
			if errors.Is(err, bufio.ErrBufferFull) {
				lc.Logger.Infof("skipping line number #%d: line too long", n)
				continue
			}

			if errors.Is(err, io.EOF) {
				// b can be != nil when EOF is returned, so we need to process it
				finishedReading = true
			} else if errors.Is(err, context.Canceled) {
				return n, latestTS, nil
			} else {
				return n, latestTS, fmt.Errorf("cannot read line in response: %w", err)
			}
		}

		if len(b) == 0 {
			continue
		}

		b = bytes.Trim(b, "\n")

		var logLine Log

		if err := json.Unmarshal(b, &logLine); err != nil {
			lc.Logger.Warnf("cannot unmarshal line in response: %s", string(b))
			continue
		}

		n++

View on GitHub (pinned to 909b515798)