[#324] Add replicator metrics

Signed-off-by: Alejandro Lopez <a.lopez@yadro.com>

pkg/services/replicator/process.go

@@ -20,6 +20,8 @@ type TaskResult interface {
 // HandleTask executes replication task inside invoking goroutine.
 // Passes all the nodes that accepted the replication to the TaskResult.
 func (p *Replicator) HandleTask(ctx context.Context, task Task, res TaskResult) {
+	p.metrics.IncInFlightRequest()
+	defer p.metrics.DecInFlightRequest()
 	defer func() {
 		p.log.Debug(logs.ReplicatorFinishWork,
 			zap.Uint32("amount of unfinished replicas", task.quantity),
@@ -69,6 +71,9 @@ func (p *Replicator) HandleTask(ctx context.Context, task Task, res TaskResult)
 			task.quantity--
 
 			res.SubmitSuccessfulReplication(task.nodes[i])
+
+			p.metrics.IncProcessedObjects()
+			p.metrics.AddPayloadSize(int64(task.obj.PayloadSize()))
 		}
 	}
 }