from mcp.server.fastmcp import FastMCP
import docker
import tempfile
import os
from pathlib import Path
from typing import Dict, List, Optional
class SandboxServer:
def __init__(self):
self.mcp = FastMCP("sandbox-server")
self.docker_client = docker.from_env()
# Map of container IDs to their info
self.containers: Dict[str, dict] = {}
# Register all tools
self._register_tools()
def _register_tools(self):
@self.mcp.tool()
async def create_container_environment(image: str, persist: bool) -> str:
"""Create a new container with the specified base image.
Args:
image: Docker image to use (e.g., python:3.9-slim, ubuntu:latest)
Returns:
Container ID of the new container
"""
try:
# Create a temporary directory for file mounting
temp_dir = tempfile.mkdtemp()
# Create container with the temp directory mounted
container = self.docker_client.containers.run(
image=image,
command="tail -f /dev/null", # Keep container running
volumes={
temp_dir: {
'bind': '/workspace',
'mode': 'rw'
}
},
working_dir='/workspace',
detach=True,
remove=not persist
)
# Store container info
self.containers[container.id] = {
'temp_dir': temp_dir,
'files': {}
}
return f"""Container created with ID: {container.id}
Working directory is /workspace
Container is ready for commands"""
except docker.errors.ImageNotFound:
return f"Error: Image {image} not found. Please verify the image name."
except Exception as e:
return f"Error creating container: {str(e)}"
@self.mcp.tool()
async def create_file_in_container(container_id: str, filename: str, content: str) -> str:
"""Create a file in the specified container.
Args:
container_id: ID of the container
filename: Name of the file to create
content: Content of the file
Returns:
Status message
"""
if container_id not in self.containers:
return f"Container {container_id} not found"
try:
container_info = self.containers[container_id]
temp_dir = container_info['temp_dir']
# Create file in the mounted directory
file_path = Path(temp_dir) / filename
with open(file_path, 'w') as f:
f.write(content)
# Update container info
container_info['files'][filename] = content
return f"File {filename} has been created in /workspace"
except Exception as e:
return f"Error creating file: {str(e)}"
@self.mcp.tool()
async def execute_command_in_container(container_id: str, command: str) -> str:
"""Execute a command in the specified container.
Args:
container_id: ID of the container
command: Command to execute
Returns:
Command output
"""
try:
container = self.docker_client.containers.get(container_id)
result = container.exec_run(
command,
workdir='/workspace',
environment={
"DEBIAN_FRONTEND": "noninteractive" # For apt-get
}
)
return result.output.decode('utf-8')
except docker.errors.NotFound:
return f"Container {container_id} not found"
except Exception as e:
return f"Error executing command: {str(e)}"
@self.mcp.tool()
async def save_container_state(container_id: str, name: str) -> str:
"""Save the current state of a container as a new image.
Args:
container_id: ID of the container to save
name: Name for the saved image (e.g., 'my-python-env:v1')
Returns:
Instructions for using the saved image
"""
try:
container = self.docker_client.containers.get(container_id)
repository, tag = name.split(':') if ':' in name else (name, 'latest')
container.commit(repository=repository, tag=tag)
return f"""Environment saved as image: {name}
To use this environment later:
1. Create new container: docker run -it {name}
2. Or use with this MCP server: create_container("{name}")
The image contains all installed packages and configurations."""
except docker.errors.NotFound:
return f"Container {container_id} not found"
except Exception as e:
return f"Error saving container: {str(e)}"
@self.mcp.tool()
async def export_dockerfile(container_id: str) -> str:
"""Generate a Dockerfile that recreates the current container state.
Args:
container_id: ID of the container to export
Returns:
Dockerfile content and instructions
"""
try:
container = self.docker_client.containers.get(container_id)
# Get container info
info = container_info = self.containers.get(container_id, {})
image = container.attrs['Config']['Image']
# Get history of commands (if available)
history = []
if 'files' in info:
history.extend([f"COPY {file} /workspace/{file}" for file in info['files'].keys()])
# Create Dockerfile content
dockerfile = [
f"FROM {image}",
"WORKDIR /workspace",
*history,
'\n# Add any additional steps needed:',
'# RUN pip install <packages>',
'# COPY <src> <dest>',
'# etc.'
]
return f"""Here's a Dockerfile to recreate this environment:
{chr(10).join(dockerfile)}
To use this Dockerfile:
1. Save it to a file named 'Dockerfile'
2. Build: docker build -t your-image-name .
3. Run: docker run -it your-image-name"""
except docker.errors.NotFound:
return f"Container {container_id} not found"
except Exception as e:
return f"Error generating Dockerfile: {str(e)}"
@self.mcp.tool()
async def exit_container(container_id: str, force: bool = False) -> str:
"""Stop and remove a running container.
Args:
container_id: ID of the container to stop and remove
force: Force remove the container even if it's running
Returns:
Status message about container cleanup
"""
try:
container = self.docker_client.containers.get(container_id)
container_info = self.containers.get(container_id, {})
# Try to stop container gracefully first
if not force:
try:
container.stop(timeout=10)
except Exception as e:
return f"Failed to stop container gracefully: {str(e)}. Try using force=True if needed."
# Remove container and cleanup
container.remove(force=force)
# Clean up temp directory if it exists
if 'temp_dir' in container_info:
try:
import shutil
shutil.rmtree(container_info['temp_dir'])
except Exception as e:
print(f"Warning: Failed to remove temp directory: {str(e)}")
# Remove from our tracking
if container_id in self.containers:
del self.containers[container_id]
return f"Container {container_id} has been stopped and removed."
except docker.errors.NotFound:
return f"Container {container_id} not found"
except Exception as e:
return f"Error cleaning up container: {str(e)}"
def run(self):
"""Start the MCP server."""
self.mcp.run()
def main():
server = SandboxServer()
server.run()
if __name__ == "__main__":
main()