[go-eth-16400] Add an option to stop geth once in sync

cmd/geth/main.go

@@ -107,6 +107,7 @@ var (
 		utils.DeveloperPeriodFlag,
 		utils.TestnetFlag,
 		utils.RinkebyFlag,
+		utils.ExitWhenSyncedFlag,
 		utils.VMEnableDebugFlag,
 		utils.NetworkIdFlag,
 		utils.RPCCORSDomainFlag,

cmd/geth/usage.go

@@ -74,6 +74,7 @@ var AppHelpFlagGroups = []flagGroup{
 			utils.NetworkIdFlag,
 			utils.TestnetFlag,
 			utils.RinkebyFlag,
+			utils.ExitWhenSyncedFlag,
 			utils.SyncModeFlag,
 			utils.GCModeFlag,
 			utils.EthStatsURLFlag,

cmd/utils/flags.go

@@ -139,6 +139,11 @@ var (
 		Name:  "rinkeby",
 		Usage: "Rinkeby network: pre-configured proof-of-authority test network",
 	}
+	ExitWhenSyncedFlag = cli.IntFlag{
+		Name:  "exit-when-synced",
+		Usage: "Exit after the chain is in sync",
+		Value: 0,
+	}
 	DeveloperFlag = cli.BoolFlag{
 		Name:  "dev",
 		Usage: "Ephemeral proof-of-authority network with a pre-funded developer account, mining enabled",
@@ -1034,6 +1039,9 @@ func SetEthConfig(ctx *cli.Context, stack *node.Node, cfg *eth.Config) {
 	if ctx.GlobalIsSet(LightServFlag.Name) {
 		cfg.LightServ = ctx.GlobalInt(LightServFlag.Name)
 	}
+	if ctx.GlobalIsSet(ExitWhenSyncedFlag.Name) {
+		cfg.ExitWhenSynced = ctx.GlobalInt(ExitWhenSyncedFlag.Name)
+	}
 	if ctx.GlobalIsSet(LightPeersFlag.Name) {
 		cfg.LightPeers = ctx.GlobalInt(LightPeersFlag.Name)
 	}

eth/config.go

@@ -87,6 +87,9 @@ type Config struct {
 	LightServ  int `toml:",omitempty"` // Maximum percentage of time allowed for serving LES requests
 	LightPeers int `toml:",omitempty"` // Maximum number of LES client peers
 
+	// Exit when sycned options
+	ExitWhenSynced	int `toml:",omitempty"`
+
 	// Database options
 	SkipBcVersionCheck bool `toml:"-"`
 	DatabaseHandles    int  `toml:"-"`

eth/downloader/downloader.go

@@ -19,6 +19,7 @@ package downloader
 
 import (
 	"errors"
+	"os"
 	"fmt"
 	"math/big"
 	"sync"
@@ -1094,6 +1095,26 @@ func (d *Downloader) fetchParts(errCancel error, deliveryCh chan dataPack, deliv
 			// If there's nothing more to fetch, wait or terminate
 			if pending() == 0 {
 				if !inFlight() && finished {
+					// Exit when synced param should be executed after defined 'value' in seconds
+					// TODO:
+					//	1. Get the flag value - ctx.GlobalInt(util.ExitWhenSyncedFlag.Name)
+					//	2. Figure out where to put this
+					exitWhenSynced := 5
+					if exitWhenSynced > 0 {
+						exitCounter := exitWhenSynced
+						ticker := time.NewTicker(time.Second * 1)
+						go func() {
+							for range ticker.C {
+								fmt.Println("Exiting sync process in ", exitCounter)
+								exitCounter -= 1
+							}
+						}()
+						time.Sleep(time.Second * time.Duration(exitWhenSynced))
+						ticker.Stop()
+						fmt.Println("Exiting sync process in ", exitCounter)
+					}
+					fmt.Println("Exit sync")
+					os.Exit(3)
 					log.Debug("Data fetching completed", "type", kind)
 					return nil
 				}