click cli read from stdin

click.py

#!/env/bin/python3

import click
import sys


@click.group()
def cli():
    pass

@cli.command()
@click.option('--compose-file', 
              help='compose file to work with',
              type=click.File('r'),
              default=sys.stdin)
def secret_hash_ini(compose_file):
    with compose_file:
        data = compose_file.read()

    print(data, end='')


if __name__ == '__main__':
    cli()

    
    
# Run
# echo thisistest | ./run.py secret-hash-ini
# based on [larsks' aswer on SO](https://stackoverflow.com/a/59830073)