What causes "Option 'field_delimiter' cannot be empty" in apache/seatunnel?

Set field_delimiter to a non-empty separator, e.g. ","

apache/seatunnel · error · IllegalArgumentException

Option 'field_delimiter' cannot be empty

Error message

Option 'field_delimiter' cannot be empty

What it means

Config validation in AzureQueueSourceConfig.validate: when the message format is TEXT, field_delimiter is required to split queue message text into record fields; an empty delimiter would prevent correct field parsing, so it is rejected at source initialization.

Source

Thrown at seatunnel-connectors-v2/connector-azure-queue-storage/src/main/java/org/apache/seatunnel/connectors/seatunnel/azure/queue/config/AzureQueueSourceConfig.java:85

                        .batchSize(config.get(AzureQueueStorageSourceOptions.BATCH_SIZE))
                        .visibilityTimeoutSeconds(
                                config.get(
                                        AzureQueueStorageSourceOptions.VISIBILITY_TIMEOUT_SECONDS))
                        .pollIntervalMillis(
                                config.get(AzureQueueStorageSourceOptions.POLL_INTERVAL_MS))
                        .maxInFlightMessages(
                                config.get(AzureQueueStorageSourceOptions.MAX_IN_FLIGHT_MESSAGES))
                        .operationTimeoutMillis(
                                config.get(AzureQueueStorageSourceOptions.OPERATION_TIMEOUT_MS))
                        .build();
        sourceConfig.validate();
        return sourceConfig;
    }

    private void validate() {
        AzureQueueConfigValidator.validateClient(this);
        if (format == MessageFormat.TEXT && fieldDelimiter.isEmpty()) {
            throw new IllegalArgumentException("Option 'field_delimiter' cannot be empty");
        }
        if (batchSize < 1 || batchSize > MAX_BATCH_SIZE) {
            throw new IllegalArgumentException("Option 'batch_size' must be between 1 and 32");
        }
        if (visibilityTimeoutSeconds < 1
                || visibilityTimeoutSeconds > MAX_VISIBILITY_TIMEOUT_SECONDS) {
            throw new IllegalArgumentException(
                    "Option 'visibility_timeout_seconds' must be between 1 and 604800");
        }
        if (pollIntervalMillis <= 0) {
            throw new IllegalArgumentException(
                    "Option 'poll_interval_ms' must be greater than zero");
        }
        if (maxInFlightMessages < batchSize) {
            throw new IllegalArgumentException(
                    "Option 'max_in_flight_messages' must be greater than or equal to batch_size");
        }
        if (operationTimeoutMillis <= 0) {

View on GitHub (pinned to cf67b549a7)

Solutions

Set field_delimiter to a non-empty separator, e.g. ","
Switch format = JSON if messages are not delimited text
Delete the field_delimiter key to fall back to the default

Example fix

// before
format = TEXT
field_delimiter = ""
// after
format = TEXT
field_delimiter = ","

Defensive patterns

Strategy: validation

Validate before calling

java
if (format == MessageFormat.TEXT && (fieldDelimiter == null || fieldDelimiter.isEmpty())) {
    fieldDelimiter = ",";
}

Try / catch

java
try {
    AzureQueueSourceConfig.from(config);
} catch (IllegalArgumentException e) {
    if (e.getMessage().equals("Option 'field_delimiter' cannot be empty")) {
        log.error("Provide a non-empty field_delimiter for TEXT format");
    } else { throw e; }
}

Prevention

Omit field_delimiter instead of setting it to ""
Match source and sink formats when round-tripping messages
Validate configs locally with a -e local dry run

When it happens

Trigger: Building AzureQueueSourceConfig via from() with MessageFormat.TEXT and field_delimiter = "".

Common situations: Empty delimiter left from a copied template; user expected the default to apply after explicitly overriding with ""; unit-config generator emitted an empty value.

Understand the failure class

Background: "Invalid value" and "allowed values are" config errors: what your library rejected and how to fix it — this error's family across 41 libraries.

Related errors

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/645ce705180e4ced. Report an issue: GitHub.