chore(monitor): monitor omni EVM gas tip cap (#2590)

Monitor omni evm gas tip cap.

issue: #2200

monitor/app/app.go

@@ -104,6 +104,7 @@ func Run(ctx context.Context, cfg Config) error {
 	go routerecon.ReconForever(ctx, network, xprov, ethClients)
 	go validator.MonitorForever(ctx, cprov)
 	go monitorPublicRPCForever(ctx, network, ethClients)
+	go monitorOmniEVMGasTipForever(ctx, network, ethClients)
 
 	select {
 	case <-ctx.Done():

monitor/app/gastip.go

@@ -0,0 +1,44 @@
+package monitor
+
+import (
+	"context"
+	"math/big"
+	"time"
+
+	"github.com/omni-network/omni/lib/ethclient"
+	"github.com/omni-network/omni/lib/log"
+	"github.com/omni-network/omni/lib/netconf"
+
+	"github.com/ethereum/go-ethereum/params"
+)
+
+// monitorOmniEVMGasTipForever monitors the suggested gas tip cap for the Omni EVM chain.
+func monitorOmniEVMGasTipForever(ctx context.Context,
+	network netconf.Network,
+	ethClients map[uint64]ethclient.Client,
+) {
+	ethCl, ok := ethClients[network.ID.Static().OmniExecutionChainID]
+	if !ok {
+		log.Error(ctx, "No eth client for omni chain", nil)
+		return
+	}
+
+	ticker := time.NewTicker(time.Second * 30)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-ticker.C:
+			tip, err := ethCl.SuggestGasTipCap(ctx)
+			if err != nil {
+				log.Warn(ctx, "Failed to get gas tip (will retry)", err)
+				continue
+			}
+
+			tipGwei := new(big.Int).Div(tip, big.NewInt(params.GWei))
+			gasTipCap.Set(float64(tipGwei.Uint64()))
+		}
+	}
+}

monitor/app/metrics.go

@@ -43,4 +43,11 @@ var (
 		Name:      "sync_diff",
 		Help:      "Sync difference (highest blocks) betweent public RPC and omni node",
 	})
+
+	gasTipCap = promauto.NewGauge(prometheus.GaugeOpts{
+		Namespace: "monitor",
+		Subsystem: "omni_evm",
+		Name:      "gas_tip_cap_gwei",
+		Help:      "Suggested OmniEVM gas tip cap in gwei",
+	})
 )