backup with empty cache results in errno24 too many open files

[Matthew Farrellee]

description -

this occurred when creating a backup after clearing the cache. it does not happen with a warm cache - tested by setting ulimit -n 10240, performing a backup, setting ulimit -n 1024 (original), performing a backup.

software -

duplicity 0.7.19
Python 2.7.18
Fedora release 30 (Thirty)

log w/ error -

# PASSPHRASE= duplicity --archive-dir /mnt/backup/cache --allow-source-mismatch --encrypt-key ABCDEFG --full-if-older-than 3M /tmp/tmp.mount /mnt/data
Synchronizing remote metadata to local cache...
[...]
Last full backup date: [...]
Traceback (innermost last):
  File "/usr/bin/duplicity", line 1581, in <module>
    with_tempdir(main)
  File "/usr/bin/duplicity", line 1567, in with_tempdir
    fn()
  File "/usr/bin/duplicity", line 1419, in main
    do_backup(action)
  File "/usr/bin/duplicity", line 1549, in do_backup
    incremental_backup(sig_chain)
  File "/usr/bin/duplicity", line 673, in incremental_backup
    globals.backend)
  File "/usr/bin/duplicity", line 435, in write_multivol
    globals.volsize)
  File "/usr/lib64/python2.7/site-packages/duplicity/gpg.py", line 378, in GPGWriteFile
    file = GPGFile(True, path.Path(filename), profile)
  File "/usr/lib64/python2.7/site-packages/duplicity/gpg.py", line 206, in __init__
    'logger': self.logger_fp})
  File "/usr/lib64/python2.7/site-packages/duplicity/gpginterface.py", line 374, in run
    create_fhs, attach_fhs)
  File "/usr/lib64/python2.7/site-packages/duplicity/gpginterface.py", line 402, in _attach_fork_exec
    pipe = os.pipe()
 OSError: [Errno 24] Too many open files

# tree /mnt/backup/cache | tail -n1
1 directory, 3787 files

[Matthew Farrellee (mattf)]

this is likely related to +bug/1878560