Before this change, if the auth proxy script returned updated config
parameters for a backend (eg the api_key changed for the backend)
rclone would continue to re-use the old backend with the old config
parameters out of the fscache.
This fixes the problem by adding a short config hash to the fs names
created by the auth proxy. They used to be `proxy-user` (where user
was as supplied to the auth proxy) and they will now be
`proxy-user-hash` where hash is a base64 encoded partial md5 hash of
the config.
These new config names will be visible in the logs so this is a user
visible change.
This changes log statements from log to fs package, which is required for --use-json-log
to properly make log output in JSON format. The recently added custom linting rule,
handled by ruleguard via gocritic via golangci-lint, warns about these and suggests
the alternative. Fixing was therefore basically running "golangci-lint run --fix",
although some manual fixup of mainly imports are necessary following that.
This adds a context.Context parameter to NewFs and related calls.
This is necessary as part of reading config from the context -
backends need to be able to read the global config.
Unfortunately bcrypt only hashes the first 72 bytes of a given input
which meant that using it on ssh keys which are longer than 72 bytes
was incorrect.
This swaps over to using sha256 which should be adequate for the
purpose of protecting in memory passwords where the unencrypted
password is likely in memory too.
