What causes "error installing beam package: %v" in apache/beam?

Use a supported Python version (e.g. 3.8–3.11) that has apache_beam wheels on PyPI

error installing beam package

Error message

error installing beam package: %v

What it means

Raised in expansionx.SetUpPythonEnvironment when installing the apache_beam package (beamPackage) into the expansion service virtualenv fails. The message includes the specific beam package spec being installed. Without apache_beam, the Python expansion service cannot start.

Solutions

Use a supported Python version (e.g. 3.8–3.11) that has apache_beam wheels on PyPI
Run the install manually in the venv to read the real pip resolution error
Ensure network/proxy access to PyPI and sufficient disk space
Remove conflicting preinstalled apache_beam/pyparsing versions in the environment chain

Example fix

// before
python3.12 -m venv venv  # no apache_beam wheel yet
// after
python3.10 -m venv venv  # supported interpreter with wheels

Defensive patterns

Strategy: validation

Validate before calling

if !supportedPythonForBeam(pyVersion) { // e.g. allow only 3.8-3.11
    return fmt.Errorf("python %s has no apache_beam wheels; use a supported version", pyVersion)
}

Try / catch

python, err := expansionx.SetUpPythonEnvironment(ctx, py, pkg, extras)
if err != nil && strings.Contains(err.Error(), "error installing beam package") {
    return fmt.Errorf("apache_beam install failed; check Python version/network and run pip manually for details: %w", err)
}

Prevention

Run a Python version with published apache_beam wheels
Preinstall apache_beam in a test venv to validate the package spec
Avoid conflicting pins (pyparsing, protobuf) in the same environment

When it happens

Trigger: startPythonExpansionService -> SetUpPythonEnvironment where `pip install <beamPackage> pyparsing==2.4.2` fails: unsatisfiable dependencies, no matching apache_beam wheel for the Python version/platform, or network failure.

Common situations: Using a Python version with no prebuilt apache_beam wheel (too new/old); PyPI unreachable; conflicts from an existing apache_beam or incompatible pyparsing; disk space or compiler missing for source builds.

Understand the failure class

Background: "not installed", "pip install", "required for": how missing-dependency errors surface across open-source libraries — this error's family across 34 libraries.

Related errors

AI-assisted analysis of apache/beam@12126d8942 (2026-09-13). Data as JSON: /api/errors/d417246dcd219d17. Report an issue: GitHub.

Appendix: source

Thrown at sdks/go/pkg/beam/core/runtime/xlangx/expansionx/download.go:475

	)
	venvPython := filepath.Join(venvDir, "bin", "python")

	if _, err := os.Stat(venvPython); err != nil {
		err := exec.Command(py, "-m", "venv", venvDir).Run()
		if err != nil {
			return "", errors.Wrap(err, "error creating new virtual environment for python expansion service")
		}
		err = exec.Command(venvPython, "-m", "pip", "install", "--upgrade", "pip").Run()
		if err != nil {
			return "", errors.Wrap(err, "error upgrading pip")
		}
		err = exec.Command(venvPython, "-m", "pip", "install", "--upgrade", "setuptools").Run()
		if err != nil {
			return "", errors.Wrap(err, "error upgrading setuptools")
		}
		err = exec.Command(venvPython, "-m", "pip", "install", beamPackage, "pyparsing==2.4.2").Run()
		if err != nil {
			return "", errors.Wrap(err, fmt.Sprintf("error installing beam package: %v", beamPackage))
		}
		if len(extraPackages) > 0 {
			cmd := []string{"-m", "pip", "install"}
			cmd = append(cmd, extraPackages...)
			err = exec.Command(venvPython, cmd...).Run()
			if err != nil {
				return "", errors.Wrap(err, "error installing dependencies")
			}
		}
		err = exec.Command(venvPython, "-c", "import apache_beam").Run()
		if err != nil {
			return "", errors.Wrap(err, "apache beam installation failed in virtualenv")
		}
	}
	return venvPython, nil
}

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