* feat(backends/s3): add warmup support before repacks and restores
This commit introduces basic support for transitioning pack files stored
in cold storage to hot storage on S3 and S3-compatible providers.
To prevent unexpected behavior for existing users, the feature is gated
behind new flags:
- `s3.enable-restore`: opt-in flag (defaults to false)
- `s3.restore-days`: number of days for the restored objects to remain
in hot storage (defaults to `7`)
- `s3.restore-timeout`: maximum time to wait for a single restoration
(default to `1 day`)
- `s3.restore-tier`: retrieval tier at which the restore will be
processed. (default to `Standard`)
As restoration times can be lengthy, this implementation preemptively
restores selected packs to prevent incessant restore-delays during
downloads. This is slightly sub-optimal as we could process packs
out-of-order (as soon as they're transitioned), but this would really
add too much complexity for a marginal gain in speed.
To maintain simplicity and prevent resources exhautions with lots of
packs, no new concurrency mechanisms or goroutines were added. This just
hooks gracefully into the existing routines.
**Limitations:**
- Tests against the backend were not written due to the lack of cold
storage class support in MinIO. Testing was done manually on
Scaleway's S3-compatible object storage. If necessary, we could
explore testing with LocalStack or mocks, though this requires further
discussion.
- Currently, this feature only warms up before restores and repacks
(prune/copy), as those are the two main use-cases I came across.
Support for other commands may be added in future iterations, as long
as affected packs can be calculated in advance.
- The feature is gated behind a new alpha `s3-restore` feature flag to
make it explicit that the feature is still wet behind the ears.
- There is no explicit user notification for ongoing pack restorations.
While I think it is not necessary because of the opt-in flag, showing
some notice may improve usability (but would probably require major
refactoring in the progress bar which I didn't want to start). Another
possibility would be to add a flag to send restores requests and fail
early.
See https://github.com/restic/restic/issues/3202
* ui: warn user when files are warming up from cold storage
* refactor: remove the PacksWarmer struct
It's easier to handle multiple handles in the backend directly, and it
may open the door to reducing the number of requests made to the backend
in the future.
* ui: restore --delete indicates number of deleted files
* adds new field `FilesDeleted` to the State struct, JSON and text progress updaters
* increment FilesDeleted count when ReportedDeletedFile
* ui: collect the files to be deleted, delete, then update the count post deletion
* docs: update scripting output fields for restore command
ui: report deleted directories and refactor function name to ReportDeletion
An attempt to replace an existing file with a hardlink previously ended
with a missing file.
Remove an existing file before trying to restore a special node. This
generalizes the existing behavior for symlinks to all special node
types.
LoadBlobsFromPack is now part of the repository struct. This ensures
that users of that method don't have to deal will internals of the
repository implementation.
The filerestorer tests now also contain far fewer pack file
implementation details.
For hardlinked files, only the first instance of that file increases the
amount of bytes to restore. All later instances only increase the file
count but not the restore size.
Gilbert Gilb's
Tesshu Flower
Srigovind Nayak
Michael Eischer
Shivashis Padhi
Viktor Szépe
Aneesh Nireshwalia
Alexander Neumann