This change checks the context whenever rclone might retry, and
doesn't retry if the current context has an error.
This fixes the pathological behaviour of `--max-duration` refusing to
exit because all the context deadline exceeded errors were being
retried.
This unfortunately meant changing the shouldRetry logic in every
backend and doing a lot of context propagation.
See: https://forum.rclone.org/t/add-flag-to-exit-immediately-when-max-duration-reached/22723
For few commands, RClone counts a error multiple times. This was fixed by
creating a new error type which keeps a flag to remember if the error has
already been counted or not. The CountError function now wraps the original
error eith the above new error type and returns it.
It was reported that v1.49.4 which was accidentally compiled with
go1.13 instead of go1.12 produced errors like this:
Failed to get StartPageToken: Get https://www.googleapis.com/drive/v3/changes/startPageToken?XXX: stream error: stream ID 1789; INTERNAL_ERROR
IO error: open file failed: Get https://www.googleapis.com/drive/v3/files/XXX?alt=media: stream error: stream ID 1781; INTERNAL_ERROR
These are errors from the http2 library. It appears that go1.13 when
communicating with google drive defaults to http2 whereas with go1.12
it doesn't.
It is unclear what is causing these errors, but retrying them since
they don't happen very often seems like a valid strategy.
This was fixed in v1.49.5 by compiling with go1.12 - this fix is
designed to work with go1.13
See: https://forum.rclone.org/t/1-49-4-plex-internal-errors-on-google-drive/12108/
The error "tls: bad record MAC" is very likely to be caused by
hardware issues. It indicates that a packet got corrupted somewhere.
As a work around, this change treats it as retriable error which
allows the chunk to get retried and the transfer to continue.
The purpose of this is to make it easier to maintain and eventually to
allow the rclone backends to be re-used in other projects without
having to use the rclone configuration system.
The new code layout is documented in CONTRIBUTING.
