apache/beam · error · ValueError

cache_root GCS bucket path is invalid.

Error message

cache_root GCS bucket path is invalid.

What it means

When cache_root points to a GCS path (gs://...), _get_gcs_cache_dir parses it and requires at least two path parts — a bucket name plus at least one object prefix component — before computing the per-pipeline cache dir. If the path is too short or oddly formed it logs the detailed reason and raises this ValueError, protecting the cache from writing to an invalid GCS location.

Source

Thrown at sdks/python/apache_beam/runners/interactive/interactive_environment.py:731

    if set_user_pipeline:
      if chain.user_pipeline and chain.user_pipeline is not pipeline:
        raise ValueError(
            'The beam_sql magic tries to query PCollections from multiple '
            'pipelines: %s and %s',
            chain.user_pipeline,
            pipeline)
      chain.user_pipeline = pipeline
    return chain

  def _get_gcs_cache_dir(self, pipeline, cache_dir):
    cache_dir_path = PurePath(cache_dir)
    if len(cache_dir_path.parts) < 2:
      _LOGGER.error(
          'GCS bucket cache path "%s" is too short to be valid. See '
          'https://cloud.google.com/storage/docs/naming-buckets for '
          'the expected format.',
          cache_dir)
      raise ValueError('cache_root GCS bucket path is invalid.')
    bucket_name = cache_dir_path.parts[1]
    assert_bucket_exists(bucket_name)
    return 'gs://{}/{}'.format('/'.join(cache_dir_path.parts[1:]), id(pipeline))

  @property
  def computing_pcollections(self):
    return self._computing_pcolls

  def mark_pcollection_computing(self, pcolls):
    """Marks the given pcolls as currently being computed."""
    self._computing_pcolls.update(pcolls)

  def unmark_pcollection_computing(self, pcolls):
    """Removes the given pcolls from the computing set."""
    self._computing_pcolls.difference_update(pcolls)

  def is_pcollection_computing(self, pcoll):
    """Checks if the given pcollection is currently being computed."""

View on GitHub (pinned to 12126d8942)

Solutions

1. Set cache_root to a full GCS path with a bucket and at least one folder, e.g. 'gs://my-bucket/cache'.
2. Verify the bucket name follows GCS naming rules (3-63 chars, lowercase, no underscores) per the docs linked in the log message.
3. Confirm the bucket exists and is accessible (assert_bucket_exists runs next and would fail otherwise).
4. Check for typos/extra slashes: 'gs:///x' or 'gs://' are invalid; use exactly 'gs://<bucket>/<prefix>'.
5. If remote caching isn't needed, use a local absolute directory path so the GCS branch is skipped.

Example fix

// before: ib.options.cache_root = 'gs://my-bucket' | // after: ib.options.cache_root = 'gs://my-bucket/interactive_cache'

from pathlib import PurePosixPath; def valid_gcs_cache_root(path): return True if not (isinstance(path, str) and path.startswith('gs://')) else (len(PurePosixPath(path[5:]).parts) >= 2 and bool(PurePosixPath(path[5:]).parts[0])); assert valid_gcs_cache_root(ib.options.cache_root)

def is_well_formed_gcs_path(s): return isinstance(s, str) and s.startswith('gs://') and '/' in s[5:]

try: ib.options.cache_root = candidate  # first recording builds cache manager | except ValueError as e: (set cache_root to 'gs://my-bucket/interactive_cache' if 'cache_root GCS' in str(e) else raise)

When it happens

Trigger: Setting ib.options.cache_root to 'gs://' alone, a bucket-only path like 'gs://mybucket' that parses to fewer than 2 parts, a malformed URL missing the bucket (e.g. 'gs:///folder'), or a typo'd path; then calling get_cache_manager via any recording/show/compute/cache usage.

Common situations: Notebooks configured for Dataproc/GCP: typos in cache_root; copying a bucket URL without a folder suffix; switching from a local temp dir to GCS without updating the format; bucket names with invalid characters breaking parsing.

Understand the failure class

Background: "Invalid URL" errors: why new URL(), URI.parse, and reqwest::Url reject your string — missing scheme, whitespace, and bad path format — this error's family across 39 libraries.

Related errors

• The given pcoll %s is not a dict, an iterable or a PCollecti
• All PCollections must belong to the same pipeline.
• The given pcoll {pcoll_container} is not a dict, an iterable
• The beam_sql magic tries to query PCollections from multiple
• PCollection not available, please run the pipeline.

AI-assisted analysis of apache/beam@12126d8942 (2026-09-13). Data as JSON: /api/errors/e1586069755d3e65. Report an issue: GitHub.