Function configure_wasi_python

Platforms/WASI/_build.py:334–384

Configure the WASI/host build.

(context, working_dir)

@subdir(lambda context: CROSS_BUILD_DIR / host_triple(context), clean_ok=True)
def configure_wasi_python(context, working_dir):
    """Configure the WASI/host build."""
    config_site = os.fsdecode(HERE / "config.site-wasm32-wasi")

    wasi_build_dir = working_dir.relative_to(CHECKOUT)

    args = {
        "WASMTIME": "wasmtime",
        "ARGV0": f"/{wasi_build_dir}/python.wasm",
        "CHECKOUT": os.fsdecode(CHECKOUT),
        "WASMTIME_CONFIG_PATH": os.fsdecode(HERE / "wasmtime.toml"),
    }
    # Check dynamically for wasmtime in case it was specified manually via
    # `--host-runner`.
    if "{WASMTIME}" in context.host_runner:
        if wasmtime := shutil.which("wasmtime"):
            args["WASMTIME"] = wasmtime
        else:
            raise FileNotFoundError(
                "wasmtime not found; download from "
                "https://github.com/bytecodealliance/wasmtime"
            )
    host_runner = context.host_runner.format_map(args)
    env_additions = {"CONFIG_SITE": config_site, "HOSTRUNNER": host_runner}
    build_python = os.fsdecode(build_python_path())
    # The path to `configure` MUST be relative, else `python.wasm` is unable
    # to find the stdlib due to Python not recognizing that it's being
    # executed from within a checkout.
    configure = [
        os.path.relpath(CHECKOUT / "configure", working_dir),
        f"--host={host_triple(context)}",
        f"--build={BUILD_DIR.name}",
        f"--with-build-python={build_python}",
    ]
    if build_python_is_pydebug():
        configure.append("--with-pydebug")
    if context.args:
        configure.extend(context.args)
    call(
        configure,
        env=updated_env(env_additions | wasi_sdk_env(context)),
        context=context,
    )

    python_wasm = working_dir / "python.wasm"
    exec_script = working_dir / "python.sh"
    with exec_script.open("w", encoding="utf-8") as file:
        file.write(f'#!/bin/sh\nexec {host_runner} {python_wasm} "$@"\n')
    exec_script.chmod(0o755)
    log("🏃", f"Created {exec_script} (--host-runner)... ")
    sys.stdout.flush()


@subdir(lambda context: CROSS_BUILD_DIR / host_triple(context))