Add support for environment variable configuration

[markrahimi]

Problem

Currently, Python Fire CLI tools require all configuration to be passed via command-line arguments. For sensitive data or frequently used configurations, this can be cumbersome and insecure.

Proposed Solution

Add support for reading configuration values from environment variables with a naming convention like FIRE_<PARAM_NAME>.

Example Usage

python import fire

def deploy(api_key, region='us-east-1'):
    """Deploy application"""
    print(f"Deploying to {region} with key {api_key}")

if __name__ == '__main__':
    fire.Fire(deploy)

Current usage (exposes secret):

‍‍python deploy.py --api-key=secret123 --region=eu-west-1

Proposed usage:

export FIRE_API_KEY=secret123
python deploy.py --region=eu-west-1

Benefits

• Security: Sensitive data not exposed in process lists
• Convenience: Reduce repetitive argument typing
• DevOps: Better integration with container/cloud environments

Alternative Considered

Using config files, but environment variables are more standard in modern deployment workflows.

[anki-code]

I can confirm that it's a good feature. In xonsh shell awesome CLI template the name of the env var formed from CLI app name (example) so if the app name myapp the env variable will be $MYAPP_<COMPONENT_NAME>_<ARGUMENT_NAME>.