Merge #1477

1477: Backport HotStuff view metric fixes from `v0.22-mainnet` r=jordanschalm a=jordanschalm

Fixes two issues with HotStuff view metric from Mainnet deployment branch:
* `HotstuffViewFun` unset caused panic on non-consensus nodes
* `hotstuffCurView` metric missing `role` label

Co-authored-by: Jordan Schalm <jordan@dapperlabs.com>
Co-authored-by: Kay-Zee <kan@axiomzen.co>
Co-authored-by: Leo Zhang (zhangchiqing) <zhangchiqing@gmail.com>
Co-authored-by: Leo Zhang <zhangchiqing@gmail.com>

cmd/scaffold.go

@@ -176,6 +176,7 @@ func (fnb *FlowNodeBuilder) EnqueueNetworkInit() {
 				}
 				return head.Height, nil
 			},
+			HotstuffViewFun: nil, // set in next code block, depending on role
 		}
 
 		// only consensus roles will need to report hotstuff view
@@ -191,6 +192,11 @@ func (fnb *FlowNodeBuilder) EnqueueNetworkInit() {
 
 				return curView, nil
 			}
+		} else {
+			// non-consensus will not report any hotstuff view
+			pingProvider.HotstuffViewFun = func() (uint64, error) {
+				return 0, fmt.Errorf("non-consensus nodes do not report hotstuff view in ping")
+			}
 		}
 
 		streamFactory, err := p2p.LibP2PStreamCompressorFactoryFunc(fnb.BaseConfig.LibP2PStreamCompression)

module/metrics/ping.go

@@ -34,7 +34,7 @@ func NewPingCollector() *PingCollector {
 			Namespace: namespaceNetwork,
 			Subsystem: subsystemGossip,
 			Help:      "the hotstuff current view",
-		}, []string{LabelNodeID, LabelNodeAddress, LabelNodeRole, LabelNodeInfo}),
+		}, []string{LabelNodeID, LabelNodeAddress, LabelNodeInfo}),
 	}
 
 	return pc
@@ -65,10 +65,17 @@ func (pc *PingCollector) NodeInfo(node *flow.Identity, nodeInfo string, version
 		LabelNodeVersion: version}).
 		Set(float64(sealedHeight))
 
-	pc.hotstuffCurView.With(prometheus.Labels{
-		LabelNodeID:      node.NodeID.String(),
-		LabelNodeAddress: node.Address,
-		LabelNodeInfo:    nodeInfo,
-	}).
-		Set(float64(hotstuffCurView))
+	// we only need this metrics from consensus nodes.
+	// since non-consensus nodes will report this metrics as well, and the value will always be 0,
+	// we can exclude metrics from non-consensus nodes by checking if the value is above 0.
+	// consensus nodes will start this metrics value with 0 as well, and won't report, but that's
+	// OK, because their hotstuff view will quickly go up and start reporting.
+	if hotstuffCurView > 0 {
+		pc.hotstuffCurView.With(prometheus.Labels{
+			LabelNodeID:      node.NodeID.String(),
+			LabelNodeAddress: node.Address,
+			LabelNodeInfo:    nodeInfo,
+		}).
+			Set(float64(hotstuffCurView))
+	}
 }