Python programs can be compiled into WASM components using the tool componentize-py. For Golem you should use our forked version of this tool, as it pins all its dependencies to the one required by Golem Cloud.

Download a prebuilt binary from the following address:

https://github.com/golemcloud/componentize-py/releases/tag/canary-golem

The easiest way to get started once the tooling is installed is to use the golem new command as described in the Quickstart.

If you prefer to do it manually, first create a WIT interface definition in your project’s wit directory:

package my:component





interface api {


  add: func(value: u64)


  get: func() -> u64


}





world component-name {


  export api


}

The next step is to generate the Python bindings from this interface description using componentize-py:

componentize-py bindings bindings

The second parameter here is the name of the Python module to be generated. This module will contain all the types described in the interface description, as well as base classes to implement the exported functions.

Let’s implement the two exported function in a main.py file:

from bindings.component_name import exports





state: int = 0





class Api(exports.Api):


    def add(self, value: int):


      global state


      print("add " + str(value))


      state = state + value 





    def get(self) -> int:


       global state


       print("get")


       return state

The name of the class must be Api! The base class is imported from the generated bindings module’s submodule which is named as the world in your WIT file. If you are not sure what name to use, check the generated bindings, in this case in bindings/exports/__init__.py.

The last step is to compile the Python program to a WASM component using componentize-py:

componentize-py componentize main -o my-template.wasm

The resulting my-template.wasm is ready to be uploaded to Golem Cloud!