this refactors umount code we already used for the testsuite into the platform module's namespace.
also, it exposes that functionality via the cli api, so users can use it via "borg umount <mountpoint>",
which is more consistent than using borg to mount and fusermount -u (or umount) to un-mount.
/mnt/backup was confusing as people like to mount their backup disk on /mnt/backup,
but borg init /mnt/backup does not work if that directory already exists because it is
the mountpoint. it would work, if /mnt was the mountpoint, but that is not obvious
and also unusual.
it's not recommended to suppress warnings or errors,
but the user may decide this on his own.
note: --warning is not given to borg serve so a <= 1.0.0 borg
will still work as server. it is not needed as it is the default.
refactorings:
- introduced concept of default answer:
if the answer string is in the defaultish sequence, the return value of yes() will be the default.
e.g. if just pressing <enter> when asked on the console or if an empty string or "default" is
in the environment variable for overriding.
if an environment var has an invalid value and no retries are enabled: return default
if retries are enabled, next retry won't use the env var again, but either ask via input().
- simplify:
only one default - this should be a SAFE default as it is used in some special conditions
like EOF or invalid input with retries disallowed.
no isatty() magic, the "yes" shell command exists, so we could receive input even if it is not from a tty.
- clean:
separate retry flag from retry_msg
one of the biggest issues with borg < 1.0 was that it had a default target chunk
size of 64kiB, thus it created a lot of chunks, a huge chunk management overhead
(high RAM and disk usage).
The fnmatch module in Python's standard library implements a pattern
format for paths which is similar to shell patterns. However, “*”
matches any character including path separators. This newly introduced
pattern syntax with the selector “sh” no longer matches the path
separator with “*”. Instead “**/” can be used to match zero or more
directory levels.
