When configuring a new target, such as an audit target, the server waits
until all audit events are sent to the audit target before doing the
swap from the old to the new audit target. Therefore current S3 operations
can suffer from this since the audit swap lock will be held.
This behavior is unnecessary as the new audit target can enter in a
functional mode immediately and the old audit will just cancel itself
at its own pace.
This PR simplifies few things by splitting
the locks between audit, logger targets to
avoid potential contention between them.
any failures inside audit/logger HTTP
targets must only log to console instead
of other targets to avoid cyclical dependency.
avoids unneeded atomic variables instead
uses RWLock to differentiate a more common
read phase v/s lock phase.
PR introduced in #13819 was incorrect and was not
handling the situation where a buffer is full can
cause incessant amount of logs that would keep the
logger webhook overrun by the requests.
To avoid this only log failures to console logger
instead of all targets as it can cause self reference,
leading to an infinite loop.
Logger targets were not race protected against concurrent updates from for example `HTTPConsoleLoggerSys`.
Restrict direct access to targets and make slices immutable so a returned slice can be processed safely without locks.
This is to ensure that there are no projects
that try to import `minio/minio/pkg` into
their own repo. Any such common packages should
go to `https://github.com/minio/pkg`
