Building Golem Components in Python

Building Golem components having an application manifest is straightforward, just use the golem command line interface:

golem app build

If the project was created using golem app new as recommended, the golem app build command will always work as expected.

The result of the golem app build command is a WebAssembly component file ready to be uploaded to Golem. It does not have to be specified explicitly, as the golem tool will automatically find the correct file when doing for example:

golem component add

Under the hood

Building Golem components written in Python involves two steps:

Package the Python code into a WASM component

The componentize subcommand of the componentize-py tool packages the Python code and the Python interpreter into a single WebAssembly component:

$ componentize-py componentize main -o py_example.wasm

Note that the componentize-py tool respects the VIRTUAL_ENV environment variable, so make sure to activate the virtualenv if there are any Python dependencies used by your component.

Reducing the size of the component

The output of compoenntize-py is large. It is possible to strip some parts of it to reduce the size by about 50% using the wasm-tools strip command:

$ wasm-tools strip -a py_example.wasm -o py_example_stripped.wasm

Generate the Python bindings from the WIT files

The bindings subcommand of the componentize-py tool generates the module containing the generated bindings:

$ componentize-py bindings generated_bindings

This will generate bindings into the bindings directory. Make sure to not actually use these bindings to invoke imported functions, as they don't have any implementation.

Defining Components Next Steps