hooks.py

def register_config_loader(self, conf_paths: Iterable[str]) -> ConfigLoader:
    return TemplatedConfigLoader(
        conf_paths,
        globals_pattern="*globals.yml",
        globals_dict={"num_workers": os.environ["num_workers"]},
    )

parameters.yml

num_workers: ${num_workers}

pipeline.py

def f(num_workers):
  print(num_workers)

# in pipeline definition include a node like this:
node(f, "params:num_workers", None)