I found upload_from_file and upload_from_filename, but is there a function or method to upload an entire folder to Cloud Storage via Python?
I don't think directly in the Python API, no, but there is in the commandline tool gsutil. You could do a system call from the python script to call out to the gsutil tool as long as you're authenticated on commandline in the shell you're calling the Python from.
The command would look something like:
gsutil -m cp -r <foldername> gs://<bucketname>
Upload a folder to Google Cloud Storage with Python?