docs/examples/storage/upload_with_metadata.py

from libcloud.storage.types import Provider
from libcloud.storage.providers import get_driver

FILE_PATH = '/home/user/myfile.tar.gz'

cls = get_driver(Provider.S3)
driver = cls('api key', 'api secret key')

container = driver.get_container(container_name='my-backups-12345')

extra = {'meta_data': {'owner': 'myuser', 'created': '2014-02-2'}}

with open(FILE_PATH, 'rb') as iterator:
    obj = driver.upload_object_via_stream(iterator=iterator,
                                          container=container,
                                          object_name='backup.tar.gz',
                                          extra=extra)