apache/beam · error · ValueError

No logical type registered for URN

Error message

No logical type registered for URN '%s'

What it means

LogicalType.from_runner_api() resolves a schema proto's logical type by its URN. If no registered LogicalType claims that URN it raises ValueError. This happens when decoding a schema produced by another pipeline/SDK version whose logical type is unknown to the current process.

Solutions

  1. Upgrade apache-beam to a version that registers the missing logical type URN.
  2. Import/register the custom LogicalType class (with matching urn()) before decoding the schema.
  3. Rewrite the data with an older/simpler schema, or strip/replace the unknown logical type in the proto.

Example fix

// before
logical_type = LogicalType.from_runner_api(proto)  # ValueError for unknown urn

// after
from my_pipeline.logical_types import MyLogicalType  # registers urn on import
LogicalType.register_logical_type(MyLogicalType)
logical_type = LogicalType.from_runner_api(proto)
Defensive patterns

Strategy: try-catch

Validate before calling

from apache_beam.typehints.schemas import LogicalType

def urn_registered(schema_proto):
    return all(
        LogicalType._known_logical_types.get_logical_type_by_urn(lt.urn) is not None
        for lt in schema_proto.logical_types)

Try / catch

try:
    lt = LogicalType.from_runner_api(logical_type_proto)
except ValueError as e:
    if "No logical type registered for URN" in str(e):
        raise RuntimeError(f"Beam version lacks logical type {logical_type_proto.urn}; upgrade apache-beam") from e
    raise

Prevention

When it happens

Trigger: Decoding a runner API schema proto (schema_pb2.Schema with a logical_type field) whose urn (e.g. a custom or newer beam:logical_type:...) has no registered LogicalType in the current Beam version/process.

Common situations: Reading data written by a newer Beam version that introduced a logical type URN not present in your installed version; custom logical types registered on the writer side but not imported on the reader side; cross-language pipelines where the Python side lacks the logical type.

Understand the failure class

Background: 'Could not be found', 'does not exist', 'not found in database': the resource-not-found family when an ID, slug, key, or URI lookup comes back empty — this error's family across 20 libraries.

Related errors

AI-assisted analysis of apache/beam@12126d8942 (2026-09-13). Data as JSON: /api/errors/b6a53fd419d323d7. Report an issue: GitHub.

Appendix: source

Thrown at sdks/python/apache_beam/typehints/schemas.py:924

    # type: (type) -> LogicalType

    """Construct an instance of this LogicalType implementation given a typing.
    """
    raise NotImplementedError()

  @classmethod
  def from_runner_api(cls, logical_type_proto):
    # type: (schema_pb2.LogicalType) -> LogicalType

    """Construct an instance of a registered LogicalType implementation given a
    proto LogicalType.

    Raises ValueError if no LogicalType registered for the given URN.
    """
    logical_type = cls._known_logical_types.get_logical_type_by_urn(
        logical_type_proto.urn)
    if logical_type is None:
      raise ValueError(
          "No logical type registered for URN '%s'" % logical_type_proto.urn)
    if not logical_type_proto.HasField(
        "argument_type") or not logical_type_proto.HasField("argument"):
      # logical type_proto without argument
      return logical_type()
    else:
      try:
        argument = value_from_runner_api(
            logical_type_proto.argument_type, logical_type_proto.argument)
      except ValueError:
        # TODO(https://github.com/apache/beam/issues/23373): Complete support
        # for logical types that require arguments beyond atomic type.
        # For now, skip arguments.
        _LOGGER.warning(
            'Logical type %s with argument is currently unsupported. '
            'Argument values are omitted',
            logical_type_proto.urn)
        return logical_type()

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