Add l1 metrics (#1678)

Co-authored-by: Kirill <paltsev.kir@gmail.com>

l1/eth_subscriber.go

@@ -20,6 +20,7 @@ type EthSubscriber struct {
 	ethClient *ethclient.Client
 	client    *rpc.Client
 	filterer  *contract.StarknetFilterer
+	listener  EventListener
 }
 
 var _ Subscriber = (*EthSubscriber)(nil)
@@ -42,6 +43,7 @@ func NewEthSubscriber(ethClientAddress string, coreContractAddress common.Addres
 		ethClient: ethClient,
 		client:    client,
 		filterer:  filterer,
+		listener:  SelectiveListener{},
 	}, nil
 }
 
@@ -50,14 +52,25 @@ func (s *EthSubscriber) WatchLogStateUpdate(ctx context.Context, sink chan<- *co
 }
 
 func (s *EthSubscriber) ChainID(ctx context.Context) (*big.Int, error) {
-	return s.ethClient.ChainID(ctx)
+	reqTimer := time.Now()
+	chainID, err := s.ethClient.ChainID(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("get chain ID: %w", err)
+	}
+	s.listener.OnL1Call("eth_chainId", time.Since(reqTimer))
+
+	return chainID, nil
 }
 
 func (s *EthSubscriber) FinalisedHeight(ctx context.Context) (uint64, error) {
+	const method = "eth_getBlockByNumber"
+	reqTimer := time.Now()
+
 	var raw json.RawMessage
-	if err := s.client.CallContext(ctx, &raw, "eth_getBlockByNumber", "finalized", false); err != nil { //nolint:misspell
+	if err := s.client.CallContext(ctx, &raw, method, "finalized", false); err != nil { //nolint:misspell
 		return 0, fmt.Errorf("get finalised Ethereum block: %w", err)
 	}
+	s.listener.OnL1Call(method, time.Since(reqTimer))
 
 	var head *types.Header
 	if err := json.Unmarshal(raw, &head); err != nil {

l1/event_listener.go

@@ -1,19 +1,29 @@
 package l1
 
 import (
+	"time"
+
 	"github.com/NethermindEth/juno/core"
 )
 
 type EventListener interface {
 	OnNewL1Head(head *core.L1Head)
+	OnL1Call(method string, took time.Duration)
 }
 
 type SelectiveListener struct {
 	OnNewL1HeadCb func(head *core.L1Head)
+	OnL1CallCb    func(method string, took time.Duration)
 }
 
 func (l SelectiveListener) OnNewL1Head(head *core.L1Head) {
 	if l.OnNewL1HeadCb != nil {
 		l.OnNewL1HeadCb(head)
 	}
 }
+
+func (l SelectiveListener) OnL1Call(method string, took time.Duration) {
+	if l.OnL1CallCb != nil {
+		l.OnL1CallCb(method, took)
+	}
+}

node/metrics.go

@@ -226,11 +226,20 @@ func makeL1Metrics() l1.EventListener {
 		Name:      "height",
 	})
 	prometheus.MustRegister(l1Height)
+	requestLatencies := prometheus.NewHistogramVec(prometheus.HistogramOpts{
+		Namespace: "l1",
+		Subsystem: "client",
+		Name:      "request_latency",
+	}, []string{"method"})
+	prometheus.MustRegister(requestLatencies)
 
 	return l1.SelectiveListener{
 		OnNewL1HeadCb: func(head *core.L1Head) {
 			l1Height.Set(float64(head.BlockNumber))
 		},
+		OnL1CallCb: func(method string, took time.Duration) {
+			requestLatencies.WithLabelValues(method).Observe(took.Seconds())
+		},
 	}
 }