I prefer not to set the ssh password in my conf file. Either I set the FTP_PASSWORD in the environment or have ssh prompt for it.
The current behavior of duply is to always include the FTP_PASSWORD variable as part of the duplicity command. If the password is not in the target path, then duply assigns FTP_PASSWORD=’’. This prevents the use of an already assigned FTP_PASSWORD, since the command line overrides the environment variable. Second, it also prevents the prompted of a password if it is not set, since duplicity/ssh will use FTP_PASSWORD=‘’ as the password and not prompt the user.
I suggest to not pass FTP_PASSWORD if it is already set, OR if it is not set and no password is specified in the target path. In the second case, the user will be prompted for the password.
As a hack, I commented out line 1549 of duply to prevent FTP_PASSWORD from being passed to duplicity and it worked fine for my two scenarios.
System Rescue CD 1.6.4