An entry is expired when it hasn't been used for a while, but the user
of the cache may know it is still doing something in the background.
SetCanExpire sets a function which is asked before expiring an entry
and can keep it in the cache until it is ready to go.
The function is called without the cache locked as it may take a
while, so an entry which is used in the meantime isn't expired.
This commit modernizes Go usage. This was done with:
go run golang.org/x/tools/gopls/internal/analysis/modernize/cmd/modernize@latest -fix -test ./...
Then files needed to be `go fmt`ed and a few comments needed to be
restored.
The modernizations include replacing
- if/else conditional assignment by a call to the built-in min or max functions added in go1.21
- sort.Slice(x, func(i, j int) bool) { return s[i] < s[j] } by a call to slices.Sort(s), added in go1.21
- interface{} by the 'any' type added in go1.18
- append([]T(nil), s...) by slices.Clone(s) or slices.Concat(s), added in go1.21
- loop around an m[k]=v map update by a call to one of the Collect, Copy, Clone, or Insert functions from the maps package, added in go1.21
- []byte(fmt.Sprintf...) by fmt.Appendf(nil, ...), added in go1.19
- append(s[:i], s[i+1]...) by slices.Delete(s, i, i+1), added in go1.21
- a 3-clause for i := 0; i < n; i++ {} loop by for i := range n {}, added in go1.22
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.
Nick Craig-Wood