apache/seatunnel · error · IOException

Unexpected auth response

Error message

Unexpected auth response: ${reply} (expected ACK or REJECTED)

What it means

handleAuthResponse expects the collector's auth reply to be exactly ACK or REJECTED (AUTH_FAILED handled separately). Any other line is thrown as this IOException with the raw reply, meaning the authentication channel returned a response outside the known protocol.

Solutions

Inspect the reply text in the exception message to see what was actually received
Confirm the target address/port is the EdgeSocket collector and no proxy intercepts the plain-text protocol
Align agent and collector to the same SeaTunnel/protocol version
If the collector sends extra banner lines, remove the banner or update the client to skip it

Defensive patterns

Strategy: try-catch

Try / catch

try { client.probeReachable(); } catch (IOException e) { if (e.getMessage().startsWith("Unexpected auth response:")) { log.error("Auth channel returned: {}", e.getMessage()); } throw e; }

Prevention

Connect directly to the collector, avoiding banner-injecting middleboxes
Keep protocol versions aligned between agent and collector
Probe reachability at startup to catch protocol skew early
Check for collector crash output corrupting the handshake reply

When it happens

Trigger: The first reply line after the AUTH line is not ACK, REJECTED, or AUTH_FAILED — e.g. a proxy/gateway banner, TLS plaintext error, wrong-port HTTP response, or protocol version mismatch.

Common situations: Connecting through a load balancer or proxy that injects a banner; pointing at a non-EdgeSocket service; collector crash mid-handshake emitting a stack trace line; version skew between agent and collector protocol.

Related errors

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/e70c9934d60c04a4. Report an issue: GitHub.

Appendix: source

Thrown at seatunnel-edge-agent/seatunnel-edge-agent-transport/src/main/java/org/apache/seatunnel/edge/agent/transport/socket/EdgeSocketLineTransport.java:101

        }
        throw new IOException(
                "Exceeded maxBatchSendAttempts="
                        + config.getMaxBatchSendAttempts()
                        + " without RECEIVED for batch "
                        + batchId);
    }

    private static void handleAuthResponse(String reply) throws IOException {
        if (EdgeSocketProtocol.RESP_REJECTED.equals(reply)) {
            throw new EdgeSocketCollectorRejectedException();
        }
        if (EdgeSocketProtocol.RESP_AUTH_FAILED.equals(reply)) {
            throw new EdgeSocketCollectorRejectedException(
                    "Edge socket authentication rejected (AUTH_FAILED): check output token matches"
                            + " EdgeSocket source secret_key");
        }
        if (!EdgeSocketProtocol.RESP_ACK.equals(reply)) {
            throw new IOException(
                    "Unexpected auth response: "
                            + reply
                            + " (expected "
                            + EdgeSocketProtocol.RESP_ACK
                            + " or "
                            + EdgeSocketProtocol.RESP_REJECTED
                            + ")");
        }
    }

    private static long parseQueueFullBackoffMs(String reply) {
        String suffix = reply.substring(EdgeSocketProtocol.RESP_QUEUE_FULL_PREFIX.length());
        try {
            long ms = Long.parseLong(suffix.trim());
            return ms > 0 ? ms : EdgeSocketProtocol.DEFAULT_QUEUE_FULL_BACKOFF_MS;
        } catch (NumberFormatException ex) {
            return EdgeSocketProtocol.DEFAULT_QUEUE_FULL_BACKOFF_MS;
        }

View on GitHub (pinned to cf67b549a7)