FTP to Google Storage

Some files get uploaded on a daily basis to an FTP server and I need those files under Google Cloud Storage. I don't want to bug the users that upload the files to install any additional software and just let them keep using their FTP client. Is there a way to use GCS as an FTP server? If not, how can I create a job that periodically picks up the files from an FTP location and puts them in GCS? In other words: what's the best and simplest way to do it?

I have successfully set up an FTP proxy to GCS using gcsfs in a VM in Google Compute (mentioned by jkff in the comment to my question), with these instructions: [url unlinked due to dangerous site] ilyapimenov.com/blog/2015/01/19/ftp-proxy-to-gcs.html

Some changes are needed though:

• In /etc/vsftpd.conf change #write_enable=YES
  to write_enable=YES
• Add firewall rules in your GC project to allow access to ports 21 and passive ports 15393 to 15592 (https://console.cloud.google.com/networking/firewalls/list)

Some possible problems:

• If you can access the FTP server using the local ip, but not the remote ip, it's probably because you haven't set up the firewall rules
• If you can access the ftp server, but are unable to write, it's probably because you need the write_enable=YES
• If you are tying to read on the folder you created on /mnt, but get a I/O error, it's probably because the bucket in gcsfs_config is not right.

Also, your ftp client needs to use the transfer mode set to "passive".