Before this patch, when an alias backend was created it would be
renamed to be canonical and in the process Shutdown would be called on
it. This was particularly noticeable with the dropbox backend which
gave this error when uploading files after the backend was Shutdown.
Failed to copy: upload failed: batcher is shutting down
This patch fixes the cache Rename code not to finalize objects if the
object that is being overwritten is the same as the existing object.
See: https://forum.rclone.org/t/upload-failed-batcher-is-shutting-down/33900
This change ensures we call the Shutdown method on backends when
they drop out of the fs/cache and at program exit.
Some backends implement the optional fs.Shutdowner interface. Until now,
Shutdown is only checked and called, when a backend is wrapped (e.g.
crypt, compress, ...).
To have a general way to perform operations at the end of the backend
lifecycle with proper error handling, we can call Shutdown at cache
clear time.
We add a finalize hook to the cache which will be called when values
drop out of the cache.
Previous discussion: https://forum.rclone.org/t/31336
This commit makes the previously statically configured fs cache configurable.
It introduces two parameters `--fs-cache-expire-duration` and
`--fs-cache-expire-interval` to control the caching of the items.
It also adds new interfaces to lib/cache to set these.
