apache/beam · error · ValueError

Did not discover any SchemaTransforms resembling the name

Error message

Did not discover any SchemaTransforms resembling the name '%s'

What it means

discover_config queried the expansion service for all SchemaTransforms and none of their identifiers contains the requested (partial) name, so the transform lookup cannot resolve which transform to configure.

Solutions

1. List available transforms from the service to see exact identifiers, then correct the name
2. Fix typos or use the fully qualified identifier (e.g. 'beam:transform:org.apache.beam:kafka_read:v1')
3. Verify the expansion service jar actually contains the transform

When it happens

Trigger: Thrown at sdks/python/apache_beam/transforms/external.py:585 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/beam@12126d8942 (2026-09-13). Data as JSON: /api/errors/a883e271cff9d817. Report an issue: GitHub.

Appendix: source

Thrown at sdks/python/apache_beam/transforms/external.py:585

    :return: one SchemaTransformsConfig that represents the discovered
        SchemaTransform

    :raises:
      ValueError: if more than one SchemaTransform is discovered, or if none
      are discovered
    """

    schematransforms = SchemaAwareExternalTransform.discover(
        expansion_service, ignore_errors=True)
    matched = []

    for st in schematransforms:
      if name in st.identifier:
        matched.append(st)

    if not matched:
      raise ValueError(
          "Did not discover any SchemaTransforms resembling the name '%s'" %
          name)
    elif len(matched) > 1:
      raise ValueError(
          "Found multiple SchemaTransforms with the name '%s':\n%s\n" %
          (name, [st.identifier for st in matched]))

    return matched[0]


class JavaExternalTransform(ptransform.PTransform):
  """A proxy for Java-implemented external transforms.

  One builds these transforms just as one would in Java, e.g.::

      transform = JavaExternalTransform('fully.qualified.ClassName'
          )(contructorArg, ... ).builderMethod(...)

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