apache/beam · error · BeamIOError

Checksum operation failed

Error message

Checksum operation failed

What it means

BlobStorageFileSystem.checksum() fetches blob checksum metadata and re-raises any exception as BeamIOError('Checksum operation failed', {path, e}). Note the source uses a set literal {path, e} instead of the dict {path: e} used elsewhere — the exception details are still attached to the BeamIOError but the path-to-error mapping is malformed.

Source

Thrown at sdks/python/apache_beam/io/azure/blobstoragefilesystem.py:280

    except Exception as e:  # pylint: disable=broad-except
      raise BeamIOError("Last updated operation failed", {path: e})

  def checksum(self, path):
    """Fetch checksum metadata of a file on the
    :class:`~apache_beam.io.filesystem.FileSystem`.

    Args:
      path: string path of a file.

    Returns: string containing checksum

    Raises:
      ``BeamIOError``: if path isn't a file or doesn't exist.
    """
    try:
      return self._blobstorageIO().checksum(path)
    except Exception as e:  # pylint: disable=broad-except
      raise BeamIOError("Checksum operation failed", {path, e})

  def metadata(self, path):
    """Fetch metadata fields of a file on the FileSystem.

    Args:
      path: string path of a file.

    Returns:
      :class:`~apache_beam.io.filesystem.FileMetadata`.

    Raises:
      ``BeamIOError``: if path isn't a file or doesn't exist.
    """
    try:
      file_metadata = self._blobstorageIO()._status(path)
      return FileMetadata(
          path, file_metadata['size'], file_metadata['last_updated'])
    except Exception as e:  # pylint: disable=broad-except

View on GitHub (pinned to 12126d8942)

Solutions

1. Verify the path points to an actual blob (not a directory-style prefix) with fs.exists / fs.metadata first
2. Inspect the BeamIOError details to identify the root Azure exception
3. Do not depend on exception_details being a {path: error} dict here due to the {path, e} set literal in the source
4. Check read permissions and credentials if the underlying error is authorization

Example fix

// before
try:
    checksum = fs.checksum(path)
except BeamIOError as e:
    handle(e.exception_details)  # expects dict, gets a set
// after
try:
    checksum = fs.checksum(path)
except BeamIOError as e:
    logging.error(f"checksum failed for {path}: {e!r}")
    raise

if not fs.exists(path):
    raise FileNotFoundError(f"no such blob: {path}")
# ensure it is a file, not a directory-style prefix
meta = fs.metadata(path)

try:
    checksum = fs.checksum(path)
except BeamIOError as e:
    logging.error("checksum failed for %s: %r", path, e)
    raise  # note: exception_details is a set here, not a dict

When it happens

Trigger: Calling fs.checksum(path) on a path that is not a file or does not exist, or when the Azure SDK raises while fetching blob properties (auth, network, permissions).

Common situations: Pointing checksum verification at a directory-style (empty-prefix) path; blob deleted between discovery and checksum; missing read permissions; relying on the malformed exception-details mapping and expecting a dict.

Understand the failure class

Background: Checksum mismatch errors: "checksum verification failed", "digest mismatch", "expected vs actual checksum" — what they mean and how to fix them — this error's family across 41 libraries.

Related errors

• Exists operation failed
• Size operation failed
• Last updated operation failed
• Metadata operation failed
• Unable to rename unequal number of sources and destinations.

AI-assisted analysis of apache/beam@12126d8942 (2026-09-13). Data as JSON: /api/errors/4093e73538d07075. Report an issue: GitHub.