sagens 0.0.0.0.4

Python bindings and client APIs for sagens microVM sandboxes.

sagens Python

Python package for managing sagens daemons and BOX workspaces.

What it includes

• Rust bindings for daemon lifecycle helpers and smoke-test server bootstrap
• A synchronous Python client for the box_api websocket protocol
• High-level classes for Daemon, Box, BoxFs, BoxCheckpoint, and BoxShell
• pytest smoke and gated full e2e coverage

Support

• Secure host path: Linux x86_64, Linux arm64 / aarch64
• macOS arm64: dev/test only with SAGENS_ISOLATION_MODE=compat and SAGENS_INSECURE_COMPAT=1
• Python versions: 3.11+ (pyo3 abi3-py311; classifiers for 3.11, 3.12, and 3.13)
• Linux secure mode requires /dev/kvm, delegated cgroup access through SAGENS_CGROUP_PARENT, and Linux Landlock support
• The current backend does not support Windows or secure macOS runtime release paths

Quickstart

Build the host binary, install the package, and run Python inside a BOX:

cargo run --bin xtask -- dev --python-package-root python
python3 -m pip install -e python[test]

python3 - <<'PY'
from tempfile import TemporaryDirectory

from sagens import Daemon

with TemporaryDirectory() as state_dir:
    with Daemon.start(state_dir=state_dir) as daemon:
        box = daemon.create_box()

        # Settings are stop-only, so set them before start or after stop.
        box.set("memory_mb", 512)
        box.set("fs_size_mib", 1024)
        box.set("cpu_cores", 2)
        box.set("network_enabled", False)

        box.start()
        box.fs.write("/workspace/input.txt", b"hello from python\n")

        result = box.exec_python(
            [
                "-c",
                (
                    "from pathlib import Path; "
                    "text = Path('/workspace/input.txt').read_text(); "
                    "print(text.strip().upper())"
                ),
            ]
        )
        print(result.stdout.decode().strip())

        box.stop()
PY

BOX settings examples

All BOX settings are updated with box.set(...) while the BOX is stopped:

box.set("memory_mb", 512)       # Guest RAM in MiB.
box.set("fs_size_mib", 1024)    # Persistent workspace disk in MiB.
box.set("cpu_cores", 2)

box.set("network_enabled", True)   # Enable network in compat mode only.
box.set("network_enabled", False)  # Disable network.

Named Images

See examples/named_images.py for building a local chromium image and creating two BOXes from it through the SDK.

Local development

Build the host binary and stage it into the package layout:

cargo run --bin xtask -- dev --python-package-root python

Install the package in editable mode:

python3 -m pip install -e python[test]

Run smoke tests:

python3 -m pytest python/tests -q

Run full e2e when runtime assets and env are ready:

SAGENS_RUN_E2E=1 python3 -m pytest python/tests/test_e2e.py -q