apache/beam · error · ValueError

Provided --prism_location URL is not an Apache Beam Github…

Error message

Provided --prism_location URL is not an Apache Beam Github Release page URL or download URL: %s

What it means

prism_runner resolves the --prism_location option into a downloadable Prism binary URL. If the value is a URL but neither a GitHub release download URL (starting with the download prefix) nor a GitHub release tag page URL (starting with the tag prefix), the library cannot map it to a binary and raises ValueError. It only accepts URLs pointing at the Apache Beam GitHub releases.

Solutions

Use the official GitHub release page URL for a specific tag, e.g. https://github.com/apache/beam/releases/tag/prism-vX.Y.Z
Or use the direct download URL starting with the GitHub download prefix
Or point --prism_location at a local prism binary path instead of a URL
Or drop --prism_location entirely and let Beam download/build Prism automatically

Example fix

// before
--prism_location=https://internal-mirror.example.com/prism
// after
--prism_location=https://github.com/apache/beam/releases/tag/prism-v2.61.0

Defensive patterns

Strategy: validation

Validate before calling

GITHUB_TAG_PREFIX = 'https://github.com/apache/beam/releases/tag/'
GITHUB_DOWNLOAD_PREFIX = 'https://github.com/apache/beam/releases/download/'
loc = options.prism_location
if loc and loc.startswith('http') and not (
        loc.startswith(GITHUB_DOWNLOAD_PREFIX) or loc.startswith(GITHUB_TAG_PREFIX)):
    raise ValueError(f'--prism_location must be a Beam GitHub release URL or local path: {loc}')

Type guard

def is_valid_prism_location(loc: str) -> bool:
    return not loc.startswith('http') or loc.startswith(GITHUB_TAG_PREFIX) or loc.startswith(GITHUB_DOWNLOAD_PREFIX)

Try / catch

try:
    server = PrismJobServer(options)
except ValueError as e:
    if 'not an Apache Beam Github' in str(e):
        logger.warning('Falling back to auto-managed prism; fix --prism_location')
        options.prism_location = None
        server = PrismJobServer(options)
    else:
        raise

Prevention

Only pass official github.com/apache/beam/releases URLs or local file paths
Validate the flag value in your launcher script before invoking Beam
Copy release URLs directly from the GitHub releases page rather than retyping them

When it happens

Trigger: Calling Beam with --prism_location set to a URL that starts with neither GITHUB_DOWNLOAD_PREFIX nor GITHUB_TAG_PREFIX (e.g. a personal mirror, an S3/HTTP link to a prism binary, or a typo'd GitHub URL). Raised in _resolve_from_location_override, invoked from _resolve_source_path when a location override is a URL.

Common situations: Pointing --prism_location at an internal artifact mirror or a direct binary URL from a non-GitHub host; pasting a GitHub 'releases' root page instead of a tag page; hand-editing the tag URL and breaking its prefix.

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

AI-assisted analysis of apache/beam@12126d8942 (2026-09-13). Data as JSON: /api/errors/d83f577d9db82ea4. Report an issue: GitHub.

Appendix: source

Thrown at sdks/python/apache_beam/runners/portability/prism_runner.py:380

      # the path with the following steps.
      pass

    # Check if the path is a URL.
    url = urllib.parse.urlparse(path)
    if not url.scheme:
      raise ValueError(
          'Unable to parse binary URL "%s". If using a full URL, make '
          'sure the scheme is specified. If using a local file xpath, '
          'make sure the file exists; you may have to first build prism '
          'using `go build `.' % (path))

    # We have a URL, see if we need to construct a valid file name.
    if path.startswith(GITHUB_DOWNLOAD_PREFIX):
      # If this URL starts with the download prefix, let it through.
      return path
    # The only other valid option is a github release page.
    if not path.startswith(GITHUB_TAG_PREFIX):
      raise ValueError(
          'Provided --prism_location URL is not an Apache Beam Github '
          'Release page URL or download URL: %s' % (path))
    # Get the root tag for this URL
    root_tag = os.path.basename(os.path.normpath(path))
    return PrismJobServer._construct_download_url(
        version, root_tag, platform.system(), platform.machine())

  @staticmethod
  def _install_from_source(version):
    """Builds and installs Prism from a Go source package.
    It first tries the local module, then falls back to @latest.
    """
    # This is a development version! Assume Go is installed.
    # Set the install directory to the cache location.
    envdict = {**os.environ, "GOBIN": PrismJobServer.BIN_CACHE}
    PRISMPKG = "github.com/apache/beam/sdks/v2/go/cmd/prism"

    _LOGGER.info(

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