stacyvm 0.1.1

Python SDK for StacyVM — self-hosted microVM sandboxes for LLMs

StacyVM Python SDK

Python client for StacyVM — self-hosted compute sandboxes for AI agents and code execution.

pip install stacyvm

• Python 3.9+.
• Sync (Client) and async (AsyncClient) APIs with identical surface.
• Single dependency: httpx.
• Type hints everywhere, ships py.typed.

---

Table of contents

• Quick start
• Connecting
• Spawning sandboxes
• Executing commands
• Streaming output
• File operations
• Live preview URLs
• Templates
• TTL and lifecycle
• Pool mode (multi-user)
• Async usage
• Server introspection
• Errors
• Type reference
• Examples

---

Quick start

from stacyvm import Client

client = Client("http://localhost:7423")

sandbox = client.spawn(image="python:3.12")
result = sandbox.exec("python3 -c 'print(40 + 2)'")
print(result.stdout)        # "42\n"

sandbox.destroy()

Or use the context manager — auto-destroys on exit:

with client.spawn(image="python:3.12") as sb:
    sb.write_file("/app/main.py", "print('hi')")
    print(sb.exec("python3 /app/main.py").stdout)
# sandbox destroyed here, even if an exception was raised

---

Connecting

from stacyvm import Client

# Simplest form
client = Client("http://localhost:7423")

# With options
client = Client(
    base_url="http://localhost:7423",
    api_key=os.environ["STACYVM_API_KEY"],
    user_id="[e-mail]",   # for pool mode
    timeout=60.0,                   # seconds, applied to all HTTP requests
)

# Use as a context manager to close the underlying httpx client
with Client("http://localhost:7423") as client:
    ...

Argument	Type	Default	Notes
base_url	str	http://localhost:7423	Server URL
api_key	str | None	None	Sent as X-API-Key header
user_id	str | None	None	Sent as X-User-ID header (pool mode)
timeout	float	30.0	Per-request timeout in seconds

---

Spawning sandboxes

sandbox = client.spawn(
    image="python:3.12",
    provider="docker",          # override server default
    memory_mb=1024,
    vcpus=2,
    ttl="1h",                   # "30s", "5m", "2h" — Go duration syntax
    owner_id="team-a",          # optional per-owner quota identity
    metadata={"user": "alice", "task": "data-analysis"},
)

All parameters are optional. Server defaults apply when omitted.

Parameter	Type	Description
image	str	Container or VM image (default alpine:latest)
provider	str | None	docker, firecracker, e2b, custom, proot, mock
memory_mb	int | None	RAM in MB
vcpus	int | None	Virtual CPUs
ttl	str | None	Auto-destroy after this duration
owner_id	str | None	Owner ID for per-owner quotas when no user_id header is set
template	str | None	Spawn from a server-side template by name
metadata	dict[str, str] | None	Free-form labels

Spawn from a template directly:

sandbox = client.spawn_template("python-dev")

Preflight quota and scheduler admission without creating a sandbox:

decision = client.admission(image="python:3.12", ttl="1h")
if not decision.allowed and decision.queueable:
    print(f"Request would queue because {decision.reason}")

---

Executing commands

result = sandbox.exec("python3 -c 'print(40+2)'")
# ExecResult(exit_code=0, stdout='42\n', stderr='', duration='127ms')

print(result.exit_code)
print(result.stdout)
print(result.duration)

With options:

result = sandbox.exec(
    "npm test",
    args=["--coverage"],            # appended to command
    env={"NODE_ENV": "test"},       # additional env vars
    workdir="/app",                 # cwd
    timeout="30s",                  # server-side kill after this duration
)

Parameter	Type	Description
command	str	Command to run
args	list[str] | None	Arguments appended to the command
env	dict[str, str] | None	Extra environment variables
workdir	str | None	Working directory inside the sandbox
timeout	str | None	Server-enforced timeout (Go duration string)

---

Streaming output

For long-running commands, stream stdout/stderr as it arrives. The server emits NDJSON; the SDK parses it into StreamChunk objects.

for chunk in sandbox.exec_stream("pip install pandas"):
    if chunk.stream == "stdout":
        print(chunk.data, end="")
    else:
        print(chunk.data, end="", file=sys.stderr)

exec_stream accepts the same arguments as exec except timeout (the connection itself bounds the session).

---

File operations

The SDK exposes the full file API. Paths are absolute inside the sandbox.

# Write
sandbox.write_file("/app/main.py", "print('hi')")
sandbox.write_file("/app/run.sh",  "#!/bin/sh\necho hi", mode="755")

# Read
code = sandbox.read_file("/app/main.py")

# List a directory
entries = sandbox.list_files("/app")
# [{"name": "main.py", "path": "/app/main.py", "size": 11, "is_dir": False, ...}, ...]

# Glob
tests = sandbox.glob_files("/app/**/*.test.py")

# Stat
info = sandbox.stat_file("/app/main.py")

# Move / rename
sandbox.move_file("/app/main.py", "/app/entry.py")

# Permissions
sandbox.chmod_file("/app/run.sh", "755")

# Delete
sandbox.delete_file("/app/temp.log")
sandbox.delete_file("/app/cache", recursive=True)

Method	Returns	Notes
write_file(path, content, mode=None)	None	mode is an octal string like "755"
read_file(path)	str	UTF-8 only — for binary, hit the REST API directly
list_files(path="/")	list[dict]	Directory entries
delete_file(path, recursive=False)	None	Set recursive=True for directories
move_file(old_path, new_path)	None	Move or rename
chmod_file(path, mode)	None	Octal string
stat_file(path)	dict	Single-entry metadata
glob_files(pattern)	list[str]	Matched paths

---

Live preview URLs

If your sandbox runs an HTTP server, get a public URL for any port. Backed by Traefik — see the main README.

sb = client.spawn(image="python:3.12")
sb.write_file("/app/server.py", """
from http.server import HTTPServer, BaseHTTPRequestHandler
class H(BaseHTTPRequestHandler):
    def do_GET(self):
        self.send_response(200); self.end_headers(); self.wfile.write(b'hi')
HTTPServer(('0.0.0.0', 3000), H).serve_forever()
""")
sb.exec("python3 /app/server.py &")

print(sb.get_preview_url(3000))
# http://3000-sb-a1b2c3d4.localhost                  (local)
# https://3000-sb-a1b2c3d4.stacyide.xyz              (production)

get_preview_url is a regular synchronous method — it builds the URL from the sandbox ID and the server's preview_domain setting. Available on both Sandbox and AsyncSandbox.

---

Templates

Templates are server-side blueprints. Define once, spawn many times.

from stacyvm import Template

# Save a template (create or update)
client.templates.save(Template(
    name="python-dev",
    image="python:3.12-slim",
    memory_mb=1024,
    vcpus=2,
    ttl="1h",
    metadata={"language": "python"},
))

# Spawn from template
sb = client.spawn(template="python-dev")
# or:
sb = client.spawn_template("python-dev")

# List / get / delete
for t in client.templates.list():
    print(t.name, t.image)

client.templates.get("python-dev")
client.templates.delete("python-dev")

---

TTL and lifecycle

Sandboxes auto-destroy after their TTL expires. Extend mid-run for long jobs.

sandbox.extend_ttl("1h")       # bump by 1 hour
sandbox.extend_ttl()           # default: "30m"

sandbox.destroy()              # immediate teardown

# Refresh cached info from the server
sandbox.refresh()
print(sandbox.state)           # up-to-date state

Reattach to an existing sandbox by ID:

sb = client.get("sb-a1b2c3d4")
sb.exec("ls /app")

---

Pool mode (multi-user)

When the server runs in pool mode (multiple users sharing each VM), pass user_id so the server scopes the workspace correctly.

client = Client(
    base_url="https://stacy.example.com",
    user_id="[e-mail]",
)

sb = client.spawn(image="python:3.12")
# sandbox now lives under /workspace/[e-mail]/ inside a shared VM

print(client.pool_status())
# {"enabled": True, "vms": 3, "max_vms": 20, "total_users": 14, "max_users_per_vm": 5}

---

Async usage

AsyncClient mirrors Client exactly — every method is async, every sandbox is an AsyncSandbox.

import asyncio
from stacyvm import AsyncClient

async def main():
    async with AsyncClient("http://localhost:7423") as client:
        async with await client.spawn(image="python:3.12") as sb:
            result = await sb.exec("python3 -c 'print(\"hi\")'")
            print(result.stdout)

            # Streaming
            async for chunk in sb.exec_stream("pip install pandas"):
                print(chunk.data, end="")

asyncio.run(main())

Behavioural notes:

• AsyncClient and AsyncSandbox support async with for cleanup.
• await sb.destroy() is the async teardown.
• sb.get_preview_url(port) is sync even on AsyncSandbox — it does no I/O.

---

Server introspection

client.health()             # {"status": "ok", "version": "0.5.1", "uptime": "2h13m"}
client.list()               # list[SandboxInfo] — all active sandboxes
client.pool_status()        # pool VM and user counts
client.quota_summary()      # QuotaSummary — redacted owner quota policy counts
client.prune()              # int — count of expired sandboxes destroyed

---

Errors

All exceptions inherit from StacyVMError. Catch the base class for general handling, or specific subclasses for granular control.

from stacyvm import (
    StacyVMError,
    SandboxNotFound,
    ProviderError,
    ConnectionError,
)

try:
    sandbox.exec("python3 main.py")
except SandboxNotFound as e:
    print(f"Sandbox {e.sandbox_id} no longer exists")
except ProviderError as e:
    print(f"Provider error ({e.code}): {e}")
except ConnectionError as e:
    print(f"Network issue: {e}")
except StacyVMError as e:
    print(f"API error ({e.code}): {e}")

Exception	When	Properties
StacyVMError	Base — any API error	code, message
SandboxNotFound	404 from server	sandbox_id, code="not_found"
ProviderError	5xx from server	code
ConnectionError	Network failure	message

---

Type reference

Public exports from stacyvm:

from stacyvm import (
    Client,
    AsyncClient,
    Sandbox,
    AsyncSandbox,
    Template,
    TemplateManager,
    # Models
    ExecResult,
    QuotaSummary,
    SandboxInfo,
    SpawnAdmissionDecision,
    StreamChunk,
    # Exceptions
    StacyVMError,
    SandboxNotFound,
    ProviderError,
    ConnectionError,
)

Selected dataclasses:

@dataclass
class ExecResult:
    exit_code: int
    stdout: str
    stderr: str
    duration: str = ""        # e.g. "127ms"

@dataclass
class SandboxInfo:
    id: str
    state: str                # "creating" | "running" | "stopped" | "destroyed" | "error"
    provider: str
    image: str
    memory_mb: int = 512
    vcpus: int = 1
    created_at: str = ""
    expires_at: str = ""
    metadata: dict = field(default_factory=dict)
    preview_domain: str = "localhost"

@dataclass
class StreamChunk:
    stream: str               # "stdout" | "stderr"
    data: str

@dataclass
class Template:
    name: str
    image: str
    memory_mb: int = 512
    vcpus: int = 1
    ttl: str = "30m"
    provider: str = ""
    metadata: dict = field(default_factory=dict)

---

Examples

Working examples live in examples/python/:

• Basic spawn → exec → destroy
• Streaming output
• Live preview (Flask/FastAPI inside a sandbox)
• Pool mode with multiple users
• Async patterns with asyncio.gather
• Template-driven workflows

---

Building from source

git clone https://github.com/StacyOs/stacyvm
cd stacyvm/sdk/python
pip install -e ".[dev]"
pytest

---

License

Apache 2.0 — see LICENSE.