pyeryx 0.1.0

Python sandbox powered by WebAssembly

PyEryx - Python Bindings for Eryx

Python bindings for the Eryx sandbox - execute Python code securely inside WebAssembly.

Installation

pip install pyeryx

Note: The package is installed as pyeryx but imported as eryx.

Or build from source using maturin:

cd crates/eryx-python
maturin develop

Quick Start

import eryx

# Create a sandbox with the embedded Python runtime
sandbox = eryx.Sandbox()

# Execute Python code in complete isolation
result = sandbox.execute('''
print("Hello from the sandbox!")
x = 2 + 2
print(f"2 + 2 = {x}")
''')

print(result.stdout)
# Output:
# Hello from the sandbox!
# 2 + 2 = 4

print(f"Execution took {result.duration_ms:.2f}ms")

Features

• Complete Isolation: Sandboxed code cannot access files, network, or system resources
• Resource Limits: Configure timeouts and memory limits
• Fast Startup: Embedded pre-compiled runtime for minimal initialization overhead
• Package Support: Load Python packages (.whl, .tar.gz) including native extensions
• Type Safe: Full type stubs for IDE support and static analysis

API Reference

Sandbox

The main class for executing Python code in isolation.

sandbox = eryx.Sandbox(
    resource_limits=eryx.ResourceLimits(
        execution_timeout_ms=5000,      # 5 second timeout
        max_memory_bytes=100_000_000,   # 100MB memory limit
    )
)

result = sandbox.execute("print('Hello!')")

Loading Packages

You can load Python packages (wheels or tar.gz archives) into the sandbox:

import eryx

# Load packages from wheel files
sandbox = eryx.Sandbox(
    packages=[
        "/path/to/jinja2-3.1.2-py3-none-any.whl",
        "/path/to/markupsafe-2.1.3-wasi.tar.gz",  # WASI-compiled native extension
    ]
)

result = sandbox.execute('''
from jinja2 import Template
template = Template("Hello, {{ name }}!")
print(template.render(name="World"))
''')

For packages with native extensions (like markupsafe), you need WASI-compiled versions. These are automatically late-linked into the WebAssembly component.

You can also mount a pre-extracted site-packages directory:

sandbox = eryx.Sandbox(site_packages="/path/to/site-packages")

ExecuteResult

Returned by sandbox.execute() with execution results:

• stdout: str - Captured standard output
• duration_ms: float - Execution time in milliseconds
• callback_invocations: int - Number of callback invocations
• peak_memory_bytes: Optional[int] - Peak memory usage (if available)

ResourceLimits

Configure execution constraints:

limits = eryx.ResourceLimits(
    execution_timeout_ms=30000,        # Max script runtime (default: 30s)
    callback_timeout_ms=10000,         # Max single callback time (default: 10s)
    max_memory_bytes=134217728,        # Max memory (default: 128MB)
    max_callback_invocations=1000,     # Max callbacks (default: 1000)
)

# Or create unlimited (use with caution!)
unlimited = eryx.ResourceLimits.unlimited()

Exceptions

• eryx.EryxError - Base exception for all Eryx errors
• eryx.ExecutionError - Python code raised an exception
• eryx.InitializationError - Sandbox failed to initialize
• eryx.ResourceLimitError - Resource limit exceeded
• eryx.TimeoutError - Execution timed out

Package Loading

Supported Formats

• .whl - Standard Python wheels (zip archives)
• .tar.gz / .tgz - Tarballs (used by wasi-wheels project)
• Directories - Pre-extracted package directories

Native Extensions

Packages containing native Python extensions (.so files compiled for WASI) are automatically detected and late-linked into the WebAssembly component. This allows packages like numpy, markupsafe, and others to work in the sandbox.

Note: You need WASI-compiled versions of native extensions, not regular Linux/macOS/Windows binaries.

Error Handling

import eryx

sandbox = eryx.Sandbox()

try:
    result = sandbox.execute("raise ValueError('oops')")
except eryx.ExecutionError as e:
    print(f"Code failed: {e}")

try:
    sandbox = eryx.Sandbox(
        resource_limits=eryx.ResourceLimits(execution_timeout_ms=100)
    )
    result = sandbox.execute("while True: pass")
except eryx.TimeoutError as e:
    print(f"Timed out: {e}")

Development

Building

# Install maturin
pip install maturin

# Build and install in development mode
maturin develop

# Build release wheel
maturin build --release

Testing

pip install pytest
pytest

License

MIT OR Apache-2.0