2017-12-19 13:16:39 +01:00

35 lines
1.2 KiB
Go

package outputs
// Observer provides an interface used by outputs to report common events on
// documents/events being published and I/O workload.
type Observer interface {
NewBatch(int) // report new batch being processed with number of events
Acked(int) // report number of acked events
Failed(int) // report number of failed events
Dropped(int) // report number of dropped events
Cancelled(int) // report number of cancelled events
WriteError(error) // report an I/O error on write
WriteBytes(int) // report number of bytes being written
ReadError(error) // report an I/O error on read
ReadBytes(int) // report number of bytes being read
}
type emptyObserver struct{}
var nilObserver = (*emptyObserver)(nil)
// NewNilObserver returns an oberserver implementation, ignoring all events.
func NewNilObserver() Observer {
return nilObserver
}
func (*emptyObserver) NewBatch(int) {}
func (*emptyObserver) Acked(int) {}
func (*emptyObserver) Failed(int) {}
func (*emptyObserver) Dropped(int) {}
func (*emptyObserver) Cancelled(int) {}
func (*emptyObserver) WriteError(error) {}
func (*emptyObserver) WriteBytes(int) {}
func (*emptyObserver) ReadError(error) {}
func (*emptyObserver) ReadBytes(int) {}