Backport of Set replication metric to 0 when losing leadership into release/1.19.x (#21687)

* backport of commit d6e0bffbce

* backport of commit 74a6463761

---------

Co-authored-by: Jorge Marey <jorgenw3@gmail.com>

agent/consul/leader.go

@@ -771,6 +771,12 @@ func (s *Server) runACLReplicator(
 
 		index, exit, err := replicateFunc(ctx, logger, lastRemoteIndex)
 		if exit {
+			metrics.SetGauge([]string{"leader", "replication", metricName, "status"},
+				0,
+			)
+			metrics.SetGauge([]string{"leader", "replication", metricName, "index"},
+				0,
+			)
 			return nil
 		}
 

agent/consul/replication.go

@@ -153,6 +153,12 @@ func (r *Replicator) Run(ctx context.Context) error {
 		// Perform a single round of replication
 		index, exit, err := r.delegate.Replicate(ctx, atomic.LoadUint64(&r.lastRemoteIndex), r.logger)
 		if exit {
+			metrics.SetGauge([]string{"leader", "replication", r.delegate.MetricName(), "status"},
+				0,
+			)
+			metrics.SetGauge([]string{"leader", "replication", r.delegate.MetricName(), "index"},
+				0,
+			)
 			return nil
 		}
 		if err != nil {