feat: gracefully shutdown node at upgrade timestamp

cmd/geth/main.go

@@ -147,6 +147,7 @@ var (
 		utils.LogDebugFlag,
 		utils.LogBacktraceAtFlag,
 		utils.ZeroFeeAddressesFlag,
+		utils.UpgradeTimestampFlag,
 	}, utils.NetworkFlags, utils.DatabaseFlags)
 
 	rpcFlags = []cli.Flag{
@@ -366,6 +367,8 @@ func startNode(ctx *cli.Context, stack *node.Node, backend ethapi.Backend, isCon
 	rpcClient := stack.Attach()
 	ethClient := ethclient.NewClient(rpcClient)
 
+	utils.ShutdownAtUpgradeTimestamp(ctx, stack, ethClient)
+
 	go func() {
 		// Open any wallets already attached
 		for _, wallet := range stack.AccountManager().Wallets() {

cmd/utils/cmd.go

@@ -21,6 +21,7 @@ import (
 	"bufio"
 	"bytes"
 	"compress/gzip"
+	"context"
 	"crypto/sha256"
 	"errors"
 	"fmt"
@@ -40,6 +41,7 @@ import (
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/eth/ethconfig"
+	"github.com/ethereum/go-ethereum/ethclient"
 	"github.com/ethereum/go-ethereum/ethdb"
 	"github.com/ethereum/go-ethereum/internal/debug"
 	"github.com/ethereum/go-ethereum/internal/era"
@@ -123,6 +125,42 @@ func StartNode(ctx *cli.Context, stack *node.Node, isConsole bool) {
 	}()
 }
 
+func ShutdownAtUpgradeTimestamp(ctx *cli.Context, n *node.Node, ethClient *ethclient.Client) {
+	upgradeTimestamp := n.Config().UpgradeTimestamp
+	if upgradeTimestamp == 0 {
+		log.Info("Upgrade timestamp is not set, skipping shutdown at upgrade timestamp")
+		return
+	}
+	log.Info("Starting goroutine to shutdown at upgrade timestamp", "upgradeTimestamp", upgradeTimestamp)
+	go func() {
+		headers := make(chan *types.Header)
+		sub, err := ethClient.SubscribeNewHead(context.Background(), headers)
+		if err != nil {
+			log.Error("ShutdownAtUpgradeTimestamp: failed to subscribe to new head", "err", err)
+			return
+		}
+		defer sub.Unsubscribe()
+		for {
+			select {
+			case <-ctx.Done():
+				log.Info("ShutdownAtUpgradeTimestamp: context cancelled, exiting goroutine")
+				return
+			case header, ok := <-headers:
+				if !ok {
+					log.Error("ShutdownAtUpgradeTimestamp: subscription closed, exiting goroutine")
+					return
+				}
+				shutdownTimestamp := upgradeTimestamp - 200 // Timestamps are in ms, block time is 200ms
+				if header.Time >= shutdownTimestamp {
+					log.Info("Final block before upgrade has been sealed, initiating shutdown", "header_timestamp", header.Time)
+					n.Close()
+					return
+				}
+			}
+		}
+	}()
+}
+
 func monitorFreeDiskSpace(sigc chan os.Signal, path string, freeDiskSpaceCritical uint64) {
 	if path == "" {
 		return

cmd/utils/flags.go

@@ -566,6 +566,12 @@ var (
 		Category:  flags.MiscCategory,
 	}
 
+	UpgradeTimestampFlag = &cli.Uint64Flag{
+		Name:     "upgrade-timestamp-ms",
+		Usage:    "Timestamp (in unix milliseconds) at which the node will shut down for upgrade",
+		Category: flags.MiscCategory,
+	}
+
 	// RPC settings
 	IPCDisabledFlag = &cli.BoolFlag{
 		Name:     "ipcdisable",
@@ -1405,6 +1411,9 @@ func SetNodeConfig(ctx *cli.Context, cfg *node.Config) {
 	if ctx.IsSet(LogDebugFlag.Name) {
 		log.Warn("log.debug flag is deprecated")
 	}
+	if ctx.IsSet(UpgradeTimestampFlag.Name) {
+		cfg.UpgradeTimestamp = ctx.Uint64(UpgradeTimestampFlag.Name)
+	}
 }
 
 func setSmartCard(ctx *cli.Context, cfg *node.Config) {

node/config.go

@@ -211,6 +211,9 @@ type Config struct {
 	EnablePersonal bool `toml:"-"`
 
 	DBEngine string `toml:",omitempty"`
+
+	// UpgradeTimestamp is approximately the timestamp where the node will shut down for upgrade.
+	UpgradeTimestamp uint64 `toml:",omitempty"`
 }
 
 // IPCEndpoint resolves an IPC endpoint based on a configured value, taking into