What causes "stagingBucketName must end with '/'" in apache/beam?

Append a '/' to the staging bucket name, e.g. change 'gs://my-bucket' to 'gs://my-bucket/'.

apache/beam · error · java.lang.IllegalArgumentException

stagingBucketName must end with '/'

Error message

stagingBucketName must end with '/'

What it means

SnowflakeWriteConfiguration.validate() requires the staging bucket name to end with a trailing slash. The Snowflake IO composes storage integration paths by directly appending to the staging bucket name, so a missing trailing slash would produce malformed GCS/S3 paths during COPY operations. The check runs eagerly at pipeline construction time via IllegalArgumentException.

Solutions

Append a '/' to the staging bucket name, e.g. change 'gs://my-bucket' to 'gs://my-bucket/'.
If the value comes from a config file or pipeline option, sanitize it before building the configuration (value.endsWith("/") ? value : value + "/").
Check the storage integration in Snowflake points at the same bucket root if paths still misbehave after the fix.

Example fix

// before
.withStagingBucketName("gs://my-snowflake-bucket")
// after
.withStagingBucketName("gs://my-snowflake-bucket/")

Defensive patterns

Strategy: validation

Validate before calling

String bucket = cfg.getStagingBucketName();
if (bucket != null && !bucket.endsWith("/")) {
  bucket = bucket + "/";
}

Try / catch

try {
  config.validate();
} catch (IllegalArgumentException e) {
  if (e.getMessage().contains("stagingBucketName")) { /* fix trailing slash and retry */ }
  throw e;
}

Prevention

Normalize bucket strings with a small helper that guarantees a trailing slash before building the configuration.
Store bucket paths in config with the trailing slash already included and document this convention.
Run configuration.validate() in unit tests with production config fixtures.

When it happens

Trigger: Calling SnowflakeWriteConfiguration (or the Snowflake write SchemaTransform) with stagingBucketName set to e.g. 'gs://my-bucket' or 'gs://my-bucket/prefix' instead of 'gs://my-bucket/' or 'gs://my-bucket/prefix/'.

Common situations: Users copy a bucket URL from the cloud console (which omits the trailing slash) or construct the path programmatically with string concatenation and forget the separator; very common in Terraform-generated or template-generated configs.

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/beam@12126d8942 (2026-09-13). Data as JSON: /api/errors/43189ddfc5b134b6. Report an issue: GitHub.

Appendix: source

Thrown at sdks/java/io/snowflake/src/main/java/org/apache/beam/sdk/io/snowflake/SnowflakeWriteConfiguration.java:139

  public static Builder builder() {
    return new AutoValue_SnowflakeWriteConfiguration.Builder();
  }

  public abstract Builder toBuilder();

  void validate() {
    requireNonEmpty(getServerName(), "serverName");
    requireNonEmpty(getDatabase(), "database");
    requireNonEmpty(getSchema(), "schema");
    requireNonEmpty(getStagingBucketName(), "stagingBucketName");
    requireNonEmpty(getStorageIntegrationName(), "storageIntegrationName");

    SnowflakeSchemaTransformUtils.validateAuthentication(
        getUsername(), getPassword(), getOauthToken(), getPrivateKey(), getPrivateKeyPassphrase());

    if (!getStagingBucketName().endsWith("/")) {
      throw new IllegalArgumentException("stagingBucketName must end with '/'");
    }

    // Parse configured enum values to validate that they are supported.
    String createDisposition = getCreateDisposition();
    if (createDisposition != null) {
      parseCreateDisposition(createDisposition);
    }

    String writeDisposition = getWriteDisposition();
    if (writeDisposition != null) {
      parseWriteDisposition(writeDisposition);
    }

    String debugMode = getDebugMode();
    if (debugMode != null) {
      parseStreamingLogLevel(debugMode);
    }

View on GitHub (pinned to 12126d8942)