Unsupported export bucket type: ${this.config.bucketType}

Error message

Unsupported export bucket type: ${this.config.bucketType}

What it means

When an export bucket is configured, PrestoDriver.unload validates that the bucketType is one of SUPPORTED_BUCKET_TYPES (e.g. s3/gcs/azure). An unsupported bucketType string throws this error before any export is attempted.

Source

Thrown at packages/cubejs-prestodb-driver/src/PrestoDriver.ts:378

  public async createSchemaIfNotExists(schemaName: string) {
    await this.query(
      `CREATE SCHEMA IF NOT EXISTS ${this.config.catalog}.${schemaName}`,
      [],
    );
  }

  // Export bucket methods
  public async isUnloadSupported() {
    return this.config.exportBucket !== undefined;
  }

  public async unload(tableName: string, options: UnloadOptions) {
    if (!this.config.exportBucket) {
      throw new Error('Export bucket is not configured.');
    }

    if (!SUPPORTED_BUCKET_TYPES.includes(this.config.bucketType as string)) {
      throw new Error(`Unsupported export bucket type: ${this.config.bucketType}`);
    }

    const types = options.query
      ? await this.unloadWithSql(tableName, options.query.sql, options.query.params)
      : await this.unloadWithTable(tableName);

    const csvFile = await this.getCsvFiles(tableName);

    return {
      exportBucketCsvEscapeSymbol: this.config.exportBucketCsvEscapeSymbol,
      csvFile,
      types,
      csvNoHeader: true,
    };
  }

  private splitTableFullName(tableFullName: string) {
    const [schema, tableName] = tableFullName.split('.');

View on GitHub (pinned to 7d981676b3)

Solutions

Set bucketType to one of the supported values (check SUPPORTED_BUCKET_TYPES: s3, gcs, azure)
Fix the typo in the exportBucket configuration
Upgrade the driver package if your storage backend's bucket type is supported only in newer versions

Example fix

// before
exportBucket: { bucketType: 'aws', bucket: 'my-bucket' }
// after
exportBucket: { bucketType: 's3', bucket: 'my-bucket', region: 'us-east-1' }

Defensive patterns

Strategy: validation

Validate before calling

const SUPPORTED = ['s3', 'gcs', 'azure'];
if (!SUPPORTED.includes(driver.config?.exportBucket?.bucketType)) {
  throw new Error(`bucketType must be one of ${SUPPORTED.join(', ')}`);
}

Type guard

const isSupportedBucketType = (t) => typeof t === 'string' && ['s3','gcs','azure'].includes(t.toLowerCase());

Try / catch

try {
  await driver.unload(tableName, options);
} catch (e) {
  if (String(e.message).startsWith('Unsupported export bucket type')) {
    console.error(`Fix exportBucket.bucketType; got: ${e.message}`);
  }
  throw e;
}

Prevention

Copy bucketType values exactly from driver docs (lowercase)
Validate exportBucket config at startup, not at export time
Pin driver versions so supported bucket types are known

When it happens

Trigger: Setting PrestoDriver exportBucket.bucketType to a typo'd or unsupported value (e.g. 's', 'aws', 'blob') and then triggering unload via the query/download pipeline.

Common situations: Typo in bucket type config; copying config from another driver that supports a different bucket type set; newer/older driver versions where the supported list differs.

Related errors

AI-assisted analysis of cube-js/cube@7d981676b3 (2026-09-02). Data as JSON: /api/errors/1ff783e5b6aa3918. Report an issue: GitHub.