WASI

wasi runs full CPython, with the whole standard library, compiled to WebAssembly and run on wasmtime inside the Mirage process. It has no host files or network: the files it opens are the workspace’s, under the same mount modes and permissions as shell commands. The first run compiles the interpreter and caches it; later runs start in milliseconds. Python SDK only.

Installation

pip install 'mirage-ai[wasi]'

Download and unzip a release from cpython-wasi-build. Point home, or MIRAGE_WASI_HOME, at the unzipped directory.

Usage

Python
YAML

from mirage import RAMVFS, MountMode, Workspace
from mirage.runtime.python import WasiRuntime

ws = Workspace(
    {"/data": RAMVFS()},
    mode=MountMode.EXEC,
    runtimes=[WasiRuntime(config={"home": "/path/to/build"})],
)
await ws.shell("python3 -c 'print(1 + 1)'")

mode: exec
runtimes:
  - name: wasi
    config:
      home: /path/to/build
mounts:
  /data:
    vfs: ram

What is wired

Anything built on these calls, such as os.path, pathlib, glob, shutil and json.load, works too.

Python	Supported	Notes
`open()` in every mode, `os.open`	Yes
`f.read()`, `os.read`, `os.pread`	Yes	Read in ranges, as the program asks.
`f.write()`, `os.write`, `os.pwrite`	Yes	Written at close or `os.fsync`.
`f.truncate()`, `os.truncate`	Yes
`os.stat`, `os.lstat`, `os.fstat`, `Path.stat`	Yes	`st_mode` has only the file type bits.
`os.listdir`, `os.scandir`, `os.walk`, `glob.glob`, `Path.glob`	Yes
`os.mkdir`, `os.makedirs`, `os.rmdir`, `shutil.rmtree`	Yes
`os.remove`, `os.unlink`, `Path.unlink`	Yes
`os.rename`, `os.replace`, `shutil.move`	Yes	`EXDEV` across mounts, where `shutil.move` copies instead.
`os.symlink`, `os.readlink`	Yes
`os.utime`, `Path.touch`	Yes
`os.getcwd`, `os.chdir`	Yes	The shell’s working directory; a change lasts for the run.
`os.environ`, `sys.argv`, `sys.stdin`	Yes	The session’s environment, the words after the script, and the piped input.
`os.chmod`	No	Does nothing.
`os.link`	No	Raises `PermissionError`.
`os.getxattr` and the other xattr calls	No	They do not exist.
`subprocess`, `socket`	No	Raise `OSError` (errno 58).

Paths outside the mounts show the CPython build, read-only.

Getting Started

Access

Policy

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Integration

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VFS

CLIs

Runtimes

Installation

Usage

What is wired

​Installation

​Usage

​What is wired

Installation

Usage

What is wired