Add flag to exit immediately when --max-duration reached

[timevortex (Parth Shukla)]

@ncw

Rclone should exit immediately on --max-duration provided --cutoff-mode is set to hard.

The documentation for --cutoff-mode says:

This modifies the behavior of --max-transfer.

I read this to mean that it doesn't impact --max-duration. Either way I haven't modified the default here so it should be set to hard.

@ncw

If it doesn't this is likely a bug...

There is a bug report about this already
https://github.com/rclone/rclone/issues/4504

Seems like the same bug (or related), specially if if you are surprised by this behaviour. I wasn't sure what the normal or expected behaviour is for this flag.

Experiment points to unexpected behaviour

From Detecting incomplete file download from Google Photos - #8 by pparth

@timevortex

I'm going re-run but with the timeout set to 2 hours (1 hour extra after --max-duration) to see if rclone also eventually gives up on files that it doesn't even start transferring. In my experiment, one file was never given up on by rclone even ~30 minutes after Google Photos API stopped responding.

So this experiment has run now at least a couple of times and I'm finding that rclone does not exit even an hour after --max-duration is reached.

Command: timeout -v --preserve-status -k 1m 7200s rclone sync --transfers=10 --max-duration=58m --retries 1 --timeout 1m --fast-list --gphotos-include-archived --gphotos-start-year=1900 --log-level INFO --log-file=REDACTED.txt gphotos:album album

Will add logs in separate replies to this thread to avoid hitting the post character limit.