[Duplicity-talk] Feedback based on restore experience

[Sergei G]

Background: My old Mac Mini failed, so I had to restore data from 
duplicity backup. Unfortunately, I experienced a set of mostly unrelated 
issues with hardware and FreeBSD 10 handling of external USB drives. 
These issues made me to try restore multiple times. My experience ended 
up focused on sftp and later ftp.

Absolutely every attempt was delayed by a single type of error message:
    CollectionsError: No backup chains found
I provide a full stack trace at the end.

The problem with this error is that it reports a consequence and not an 
issue. Duplicity failed to get to the desired source directory, but it 
fails to report the preceding error.

For example, If FTP user's root is /home/userName, but backup is at 
/mnt/extufs/, FTP client will fail to cd to the new directory, while 
interactive console will have no problem.  FTP failure to change path is 
not properly reported and that's the preceding error.

From what I remember the absolute form of sftp was one of the reasons 
for the same error message. I think sftp properly reports failure to cd 
to the remote directory. In my case, I was using 
sftp://address@hidden/abs/path/to/dir, but I should've used 
sftp://address@hidden//abs/path/to/dir. RTFM, but reporting a hint would be nice.

I usually had to find answers using other programs to questions:

1. What's my login remote directory? Is it the same as in other program 
I used?
2. What's my current remote directory when error occurred?

Answers to both questions from duplicity itself would make my life 
easier when troubleshooting.

Another set of problems was connected to incomplete error reporting when 
calling command line programs. I had a missing gpg command and I could 
not figure out its name, but its arguments were reported in the error 
message. I actually had to add print statements to source code to see 
what's the name of the missing application.


Here is a full stack trace for the typical FTP error:

NcFTP version is 3.2.5
Local and Remote metadata are synchronized, no sync needed.
Last full backup date: none
Traceback (most recent call last):
  File "/Users/sergei/.py-virtualenvs/duplicity/bin/duplicity", line 
1502, in <module>
    with_tempdir(main)
  File "/Users/sergei/.py-virtualenvs/duplicity/bin/duplicity", line 
1496, in with_tempdir
    fn()
  File "/Users/sergei/.py-virtualenvs/duplicity/bin/duplicity", line 
1345, in main
    do_backup(action)
  File "/Users/sergei/.py-virtualenvs/duplicity/bin/duplicity", line 
1430, in do_backup
    restore(col_stats)
  File "/Users/sergei/.py-virtualenvs/duplicity/bin/duplicity", line 
693, in restore
    restore_get_patched_rop_iter(col_stats)):
  File "/Users/sergei/.py-virtualenvs/duplicity/bin/duplicity", line 
715, in restore_get_patched_rop_iter
    backup_chain = col_stats.get_backup_chain_at_time(time)
  File 
"/Users/sergei/.py-virtualenvs/duplicity/lib/python2.7/site-packages/duplicity/collections.py", 
line 952, in get_backup_chain_at_time
    raise CollectionsError("No backup chains found")
CollectionsError: No backup chains found