fermion-sandbox 0.1.1

Secure isolated code execution SDK for Python

fermion-sandbox

Secure isolated code execution SDK for Python. Run untrusted code, build projects, or host services in ephemeral containers.

Installation

pip install fermion-sandbox

Quick Start

import asyncio
import os
from fermion_sandbox import Sandbox

async def main():
    # Get API key from environment
    api_key = os.getenv('FERMION_API_KEY')
    if not api_key:
        raise ValueError("FERMION_API_KEY environment variable is required")

    # Create sandbox
    sandbox = Sandbox(api_key=api_key)
    await sandbox.create(should_backup_filesystem=False)

    # Execute commands
    result = await sandbox.run_command(cmd='node', args=['--version'])
    print(result.stdout)

    # Write and read files
    await sandbox.write_file(
        path='~/script.js',
        content='console.log("Hello World")'
    )

    response = await sandbox.get_file('~/script.js')
    content = response.text

    # Clean up
    await sandbox.disconnect()

asyncio.run(main())

Note: Set your API key as an environment variable: export FERMION_API_KEY='your-api-key'

Key Features

• Isolated containers - Secure Linux environments for code execution
• Real-time streaming - WebSocket-based command output streaming
• File operations - Read/write files with binary support
• Public URLs - Expose ports 3000, 1337, 1338 for web services
• Git support - Clone repositories on container startup
• Type safety - Full type hints with Pydantic models
• Async/await - Built on asyncio for modern Python applications

Core API

Creating a Sandbox

sandbox = Sandbox(api_key='your-api-key')

# New container
await sandbox.create(
    should_backup_filesystem=False,  # Persist filesystem after shutdown
    git_repo_url='https://github.com/user/repo.git'  # Optional
)

# Or connect to existing
await sandbox.from_snippet('snippet-id')

Running Commands

# Quick commands (< 5 seconds)
result = await sandbox.run_command(
    cmd='ls',
    args=['-la']
)
print(result.stdout, result.stderr)

# Long-running with streaming
result = await sandbox.run_streaming_command(
    cmd='npm',
    args=['install'],
    on_stdout=lambda data: print(data),
    on_stderr=lambda data: print(data)
)
print(f"Exit code: {result.exit_code}")

File Operations

# Write file
await sandbox.write_file(
    path='~/app.js',
    content='console.log("Hello")'
)

# Read file
response = await sandbox.get_file('~/app.js')
text = response.text
binary_data = response.content

Web Services

# Start a server
asyncio.create_task(sandbox.run_streaming_command(
    cmd='node',
    args=['server.js']
))

# Get public URL
url = await sandbox.expose_port(3000)
print(f'Live at: {url}')
# https://abc123-3000.run-code.com

Quick Code Execution

# Execute code without full sandbox
result = await sandbox.quick_run(
    runtime='Python',
    source_code='print("Hello, World!")'
)

if result.program_run_data:
    stdout = result.program_run_data.stdout_base64_url_encoded or ''
    print(stdout)

Examples

Run a Node.js Project

import asyncio
from fermion_sandbox import Sandbox

async def main():
    sandbox = Sandbox(api_key='your-api-key')
    await sandbox.create(
        should_backup_filesystem=False,
        git_repo_url='https://github.com/user/node-app.git'
    )

    # Install dependencies
    await sandbox.run_streaming_command(
        cmd='npm',
        args=['install'],
        on_stdout=lambda data: print(data.strip())
    )

    # Build project
    await sandbox.run_command(cmd='npm', args=['run', 'build'])

    # Start server
    asyncio.create_task(sandbox.run_streaming_command(
        cmd='npm',
        args=['start']
    ))

    # Get public URL
    url = await sandbox.expose_port(3000)
    print(f'App running at: {url}')

    # Keep running
    await asyncio.sleep(60)
    await sandbox.disconnect()

asyncio.run(main())

Execute C++ Code

from fermion_sandbox import Sandbox

async def main():
    sandbox = Sandbox(api_key='your-api-key')

    result = await sandbox.quick_run(
        runtime='C++',
        source_code='''
            #include <iostream>
            using namespace std;
            int main() {
                int a, b;
                cin >> a >> b;
                cout << a + b << endl;
                return 0;
            }
        ''',
        stdin='5 3',
        expected_output='8'
    )

    print(f"Status: {result.run_status}")
    if result.program_run_data:
        stdout = result.program_run_data.stdout_base64_url_encoded or ''
        print(f"Output: {stdout}")

asyncio.run(main())

API Reference

Sandbox Class

Constructor

Sandbox(api_key: str)

Initialize sandbox client with API key.

Methods

async create(should_backup_filesystem: bool, git_repo_url: Optional[str] = None) -> str

• Create new container
• Returns: snippet ID

async from_snippet(playground_snippet_id: str) -> None

• Connect to existing container

async run_command(cmd: str, args: Optional[list[str]] = None) -> CommandResult

• Execute command (< 5s timeout)
• Returns: CommandResult with stdout, stderr

async run_streaming_command(...) -> CommandResult

• Execute with streaming output
• Callbacks: on_stdout, on_stderr
• Returns: CommandResult with stdout, stderr, exit_code

async write_file(path: str, content: Union[str, bytes]) -> None

• Write file to container

async get_file(path: str) -> httpx.Response

• Read file from container
• Returns: Response object (use .text or .content)

async expose_port(port: Literal[3000, 1337, 1338]) -> str

• Get public URL for port

get_public_urls() -> Dict[int, str]

• Get all available public URLs

async disconnect() -> None

• Clean up resources

is_connected() -> bool

• Check connection status

async quick_run(...) -> DsaExecutionResult

• Execute code without full sandbox
• Supported runtimes: C, C++, Java, Python, Node.js, SQLite, MySQL, Go, Rust, .NET

File Paths

All paths must start with ~ (home) or /home/damner:

• ~/file.js → /home/damner/file.js
• /home/damner/app/index.js → absolute path
• /home/damner/code/app/index.js → also supported (nested under home)

Supported Ports

Public URLs available for:

• Port 3000
• Port 1337
• Port 1338

Requirements

• Python 3.8+
• httpx
• websockets
• pydantic

Development

# Install with dev dependencies
pip install -e ".[dev]"

# Run tests
pytest

# Format code
black fermion_sandbox/

# Type checking
mypy fermion_sandbox/

Examples Directory

Check the examples/ directory for more usage examples:

• basic_usage.py - Basic commands and file operations
• streaming_command.py - Real-time streaming output
• quick_run.py - Quick code execution
• web_server.py - Running web servers with public URLs

Running Examples

Set your API key and run any example:

# Set API key inline (recommended)
FERMION_API_KEY='your-api-key' python examples/basic_usage.py

# Or export for current terminal session
export FERMION_API_KEY='your-api-key'
python examples/basic_usage.py

Running Tests

# Unit tests (no API key needed)
pytest tests/test_utils.py tests/test_types.py

# Integration tests (API key required)
FERMION_API_KEY='your-api-key' pytest tests/test_integration.py

# All tests
FERMION_API_KEY='your-api-key' pytest tests/

License

MIT

Support

For issues and questions, visit GitHub Issues.

Related

• Node.js SDK - Official TypeScript/JavaScript SDK
• Documentation - Full API documentation