The channel-based algorithm had grown quite complicated. This is easier
to reason about and likely to be more performant with very many
CompleteBlob calls.
FindFilteredSnapshots no longer prints errors during snapshot loading on
stderr, but instead passes the error to the callback to allow the caller
to decide on what to do.
In addition, it moves the logic to handle an explicit snapshot list from
the main package to restic.
The helper function uidGidInt used strconv.ParseInt instead of
ParseUint, so it silently ignored some invalid user/group IDs.
Also, improve the error message. "Invalid UID" is more informative than
having "ParseInt" twice (*strconv.NumError displays the function name).
Finally, the user.User struct can be passed by pointer to get reduce
code size.
This package is no longer needed, since we can use the stdlib's
http.NewRequestWithContext.
backend/rclone already did, but it needed a different error check due to
a difference between net/http and ctxhttp.
Also, store the http.Client by value in the REST backend (changed to a
pointer when ctxhttp was introduced) and use errors.WithStack instead
of errors.Wrap where the message was no longer accurate. Errors from
http.NewRequestWithContext will start with "net/http" or "net/url", so
they're easy to identify.
The backup command failed if a directory contains duplicate entries.
Downgrade the severity of this problem from fatal error to a warning.
This allows users to still create a backup.
SaveTree did not use the TreeSaver but rather managed the tree
collection and upload itself. This prevents using the parallelism
offered by the TreeSaver and duplicates all related code. Using the
TreeSaver can provide some speed-ups as all steps within the backup tree
now rely on FutureNodes. This can be especially relevant for backups
with large amounts of explicitly specified files.
The main difference between SaveTree and SaveDir is, that only the
former can save tree blobs in which nodes have a different name than the
actual file on disk. This is the result of resolving name conflicts
between multiple files with the same name. The filename that must be
used within the snapshot is now passed directly to
restic.NodeFromFileInfo. This ensures that a FutureNode already contains
the correct filename.
According to the documentation of exec.Cmd Wait() must not be called
before completing all reads from the pipe returned by StdErrPipe(). Thus
return a context that is canceled once rclone has exited and use that as
a precondition to calling Wait(). This should ensure that all errors
printed to stderr have been copied first.
When rclone fails during the connection setup this currently often
results in a context canceled error. Replace this error with the exit
code from rclone.
When backing up many small files, the unbuffered channels frequently
cause the FileSaver to block when reporting progress information. Thus,
add buffers to these channels to avoid unnecessary scheduling.
As the status information is purely informational, it doesn't matter
that the status reporting shutdown is somewhat racy and could miss a few
final updates.
The only use cases in the code were in errors.IsFatal, backend/b2,
which needs a workaround, and backend.ParseLayout. The last of these
requires all backends to implement error unwrapping in IsNotExist.
All backends except gs already did that.
