Create new code paths for multiple subsystems in the code. This will
make maintaing this easier later.
Also introduce bugLogIf() for errors that should not happen in the first
place.
A new middleware function is added for admin handlers, including options
for modifying certain behaviors. This admin middleware:
- sets the handler context via reflection in the request and sends AuditLog
- checks for object API availability (skipping it if a flag is passed)
- enables gzip compression (skipping it if a flag is passed)
- enables header tracing (adding body tracing if a flag is passed)
While the new function is a middleware, due to the flags used for
conditional behavior modification, which is used in each route registration
call.
To try to ensure that no regressions are introduced, the following
changes were done mechanically mostly with `sed` and regexp:
- Remove defer logger.AuditLog in admin handlers
- Replace newContext() calls with r.Context()
- Update admin routes registration calls
Bonus: remove unused NetSpeedtestHandler
Since the new adminMiddleware function checks for object layer presence
by default, we need to pass the `noObjLayerFlag` explicitly to admin
handlers that should work even when it is not available. The following
admin handlers do not require it:
- ServerInfoHandler
- StartProfilingHandler
- DownloadProfilingHandler
- ProfileHandler
- SiteReplicationDevNull
- SiteReplicationNetPerf
- TraceHandler
For these handlers adminMiddleware does not check for the object layer
presence (disabled by passing the `noObjLayerFlag`), and for all other
handlers, the pre-check ensures that the handler is not called when the
object layer is not available - the client would get a
ErrServerNotInitialized and can retry later.
This `noObjLayerFlag` is added based on existing behavior for these
handlers only.
