Make validation process perpetual (#8)

* Make validation process perpetual

* Get sleep interval from config

* Add license

* Gracefully shutdown validator on interrupt

* Change default trail and sleep values

cmd/state_validator.go

@@ -3,6 +3,9 @@ package cmd
 import (
 	"context"
 	"fmt"
+	"os"
+	"os/signal"
+	"sync"
 
 	"github.com/ethereum/go-ethereum/statediff"
 	log "github.com/sirupsen/logrus"
@@ -36,6 +39,7 @@ func stateValidator() {
 		logWithCommand.Fatalf("block height cannot be less the 1")
 	}
 	trail := viper.GetUint64("validate.trail")
+	sleepInterval := viper.GetUint("validate.sleepInterval")
 
 	chainConfigPath := viper.GetString("ethereum.chainConfig")
 	chainCfg, err := statediff.LoadConfig(chainConfigPath)
@@ -43,26 +47,31 @@ func stateValidator() {
 		logWithCommand.Fatal(err)
 	}
 
-	srvc := validator.NewService(cfg.DB, height, trail, chainCfg)
+	service := validator.NewService(cfg.DB, height, trail, sleepInterval, chainCfg)
 
-	_, err = srvc.Start(context.Background())
-	if err != nil {
-		logWithCommand.Fatal(err)
-	}
+	wg := new(sync.WaitGroup)
+	wg.Add(1)
+	go service.Start(context.Background(), wg)
 
-	logWithCommand.Println("state validation complete")
+	shutdown := make(chan os.Signal, 1)
+	signal.Notify(shutdown, os.Interrupt)
+	<-shutdown
+	service.Stop()
+	wg.Wait()
 }
 
 func init() {
 	rootCmd.AddCommand(stateValidatorCmd)
 
 	stateValidatorCmd.PersistentFlags().String("block-height", "1", "block height to initiate state validation")
-	stateValidatorCmd.PersistentFlags().String("trail", "0", "trail of block height to validate")
+	stateValidatorCmd.PersistentFlags().String("trail", "16", "trail of block height to validate")
+	stateValidatorCmd.PersistentFlags().String("sleep-interval", "10", "sleep interval in seconds after validator has caught up to (head-trail) height")
 
 	stateValidatorCmd.PersistentFlags().String("chain-config", "", "path to chain config")
 
 	_ = viper.BindPFlag("validate.block-height", stateValidatorCmd.PersistentFlags().Lookup("block-height"))
 	_ = viper.BindPFlag("validate.trail", stateValidatorCmd.PersistentFlags().Lookup("trail"))
+	_ = viper.BindPFlag("validate.sleepInterval", stateValidatorCmd.PersistentFlags().Lookup("sleep-interval"))
 
 	_ = viper.BindPFlag("ethereum.chainConfig", stateValidatorCmd.PersistentFlags().Lookup("chain-config"))
 }