apache/seatunnel · error · SlackConnectorException

WRITE_TO_SLACK_CHANNEL_FAILED

WRITE_TO_SLACK_CHANNEL_FAILED

Error message

Write to Slack Fail.

What it means

SlackWriter.write posts a message to a Slack channel via SlackClient.publishMessage, then sleeps ~1s to respect Slack's send-rate limits. Any exception — publish failure, network error, or interruption during sleep — is logged and rethrown as SlackConnectorException with code WRITE_TO_SLACK_CHANNEL_FAILED. It signals the sink could not deliver a message to the configured conversation.

Solutions

  1. Check the logged ExceptionUtils.getMessage(e) for the root cause (auth vs channel vs rate limit).
  2. Verify the bot token has chat:write scope and the bot is invited to the target channel.
  3. Confirm the conversation ID is valid and the channel is active.
  4. Reduce sink parallelism/throughput or add buffering if hitting Slack rate limits.
  5. Treat InterruptedException specially if job cancellation is repeatedly triggering this error.

Example fix

// before: broad catch turns cancellation into a write failure
catch (Exception e) { throw new SlackConnectorException(..., e); }
// after
try {
    slackClient.publishMessage(conversationId, message);
} catch (InterruptedException e) {
    Thread.currentThread().interrupt();
    return; // honor cancellation
} catch (Exception e) {
    throw new SlackConnectorException(WRITE_TO_SLACK_CHANNEL_FAILED, e);
}
Defensive patterns

Strategy: retry

Validate before calling

// pre-check channel membership and scope
callSlackApi("conversations.info", Map.of("channel", conversationId)); // validates channel + access

Try / catch

try {
    slackWriter.write(conversationId, message);
} catch (SlackConnectorException e) {
    if (isRateLimited(e)) {
        Thread.sleep(backoff); retry();
    } else {
        log.error("Permanent Slack write failure: {}", ExceptionUtils.getMessage(e));
        throw e;
    }
}

Prevention

When it happens

Trigger: write(conversationId, message) fails because publishMessage throws (invalid channel ID, invalid/expired token, missing chat:write scope, message rejected, rate limit) or Thread.sleep is interrupted (InterruptedException caught by the broad catch(Exception)).

Common situations: Wrong channel ID after channel deletion/archival; bot lacking chat:write scope or not a member of the channel; Slack 429 rate limits on high-throughput sinks; job cancellation interrupting the rate-limit sleep.

Related errors

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/e1d4b13e7d9a2a55. Report an issue: GitHub.

Appendix: source

Thrown at seatunnel-connectors-v2/connector-slack/src/main/java/org/apache/seatunnel/connectors/seatunnel/slack/sink/SlackWriter.java:62

        this.conversationId = slackClient.findConversation();
    }

    @Override
    public void write(SeaTunnelRow element) throws IOException {
        Object[] fields = element.getFields();
        StringJoiner stringJoiner = new StringJoiner(",", "", "\n");
        for (Object field : fields) {
            stringJoiner.add(String.valueOf(field));
        }
        String message = stringJoiner.toString();
        try {
            slackClient.publishMessage(conversationId, message);
            // Slack has a limit on the frequency of sending messages
            // One message can be sent as soon as one second
            Thread.sleep(POST_MSG_WAITING_TIME);
        } catch (Exception e) {
            log.error("Write to Slack Fail.", ExceptionUtils.getMessage(e));
            throw new SlackConnectorException(
                    SlackConnectorErrorCode.WRITE_TO_SLACK_CHANNEL_FAILED, e);
        }
    }

    @Override
    public void close() throws IOException {}
}

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