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A WebAssembly runtime powered by Wasmtime

Project description


Python embedding of Wasmtime

A Bytecode Alliance project

CI status Latest Version Latest Version Documentation Code Coverage


To install wasmtime-py, run this command in your terminal:

$ pip install wasmtime

The package currently supports 64-bit builds of Python 3.6+ on x86_64 Windows, macOS, and Linux


In this example, we compile and instantiate a WebAssembly module and use it from Python:

from wasmtime import Store, Module, Instance, Func, FuncType

store = Store()
module = Module(store.engine, """
    (func $hello (import "" "hello"))
    (func (export "run") (call $hello))

def say_hello():
    print("Hello from Python!")
hello = Func(store, FuncType([], []), say_hello)

instance = Instance(store, module, [hello])
run = instance.exports(store)["run"]

Be sure to check out the examples directory, which has other usage patterns as well as the full API documentation of the wasmtime-py package.

If your WebAssembly module works this way, then you can also import the WebAssembly module directly into Python without explicitly compiling and instantiating it yourself:

# Import the custom loader for `*.wasm` files
import wasmtime.loader

# Assuming `your_wasm_file.wasm` is in the python load path...
import your_wasm_file

# Now you're compiled and instantiated and ready to go!



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