From 639e3072fe5f7cc335ad25d8b4a6cb386ad03a41 Mon Sep 17 00:00:00 2001
From: Nishant Das <nishdas93@gmail.com>
Date: Mon, 20 Apr 2020 12:04:45 +0800
Subject: [PATCH] Cancel Initial Sync Properly (#5529)

* fix cancelling
* Merge branch 'master' into cancelServices
* Merge refs/heads/master into cancelServices
* Merge refs/heads/master into cancelServices
---
 beacon-chain/sync/initial-sync-old/service.go |  6 +-
 beacon-chain/sync/initial-sync/service.go     |  6 +-
 beacon-chain/sync/service.go                  | 60 +++++++++----------
 3 files changed, 40 insertions(+), 32 deletions(-)

diff --git a/beacon-chain/sync/initial-sync-old/service.go b/beacon-chain/sync/initial-sync-old/service.go
index adc89b71e94e..14abc93863ef 100644
--- a/beacon-chain/sync/initial-sync-old/service.go
+++ b/beacon-chain/sync/initial-sync-old/service.go
@@ -47,6 +47,7 @@ type Config struct {
 // Service service.
 type Service struct {
 	ctx               context.Context
+	cancel            context.CancelFunc
 	chain             blockchainService
 	p2p               p2p.P2P
 	db                db.ReadOnlyDatabase
@@ -60,8 +61,10 @@ type Service struct {
 // NewInitialSync configures the initial sync service responsible for bringing the node up to the
 // latest head of the blockchain.
 func NewInitialSync(cfg *Config) *Service {
+	ctx, cancel := context.WithCancel(context.Background())
 	return &Service{
-		ctx:               context.Background(),
+		ctx:               ctx,
+		cancel:            cancel,
 		chain:             cfg.Chain,
 		p2p:               cfg.P2P,
 		db:                cfg.DB,
@@ -139,6 +142,7 @@ func (s *Service) Start() {
 
 // Stop initial sync.
 func (s *Service) Stop() error {
+	s.cancel()
 	return nil
 }
 
diff --git a/beacon-chain/sync/initial-sync/service.go b/beacon-chain/sync/initial-sync/service.go
index 1fa04e8adffd..10501d9038aa 100644
--- a/beacon-chain/sync/initial-sync/service.go
+++ b/beacon-chain/sync/initial-sync/service.go
@@ -47,6 +47,7 @@ type Config struct {
 // Service service.
 type Service struct {
 	ctx               context.Context
+	cancel            context.CancelFunc
 	chain             blockchainService
 	p2p               p2p.P2P
 	db                db.ReadOnlyDatabase
@@ -60,8 +61,10 @@ type Service struct {
 // NewInitialSync configures the initial sync service responsible for bringing the node up to the
 // latest head of the blockchain.
 func NewInitialSync(cfg *Config) *Service {
+	ctx, cancel := context.WithCancel(context.Background())
 	return &Service{
-		ctx:               context.Background(),
+		ctx:               ctx,
+		cancel:            cancel,
 		chain:             cfg.Chain,
 		p2p:               cfg.P2P,
 		db:                cfg.DB,
@@ -157,6 +160,7 @@ func (s *Service) Start() {
 
 // Stop initial sync.
 func (s *Service) Stop() error {
+	s.cancel()
 	return nil
 }
 
diff --git a/beacon-chain/sync/service.go b/beacon-chain/sync/service.go
index cf3967ce11b6..362d1f74ddee 100644
--- a/beacon-chain/sync/service.go
+++ b/beacon-chain/sync/service.go
@@ -62,36 +62,6 @@ type blockchainService interface {
 	blockchain.GenesisFetcher
 }
 
-// NewRegularSync service.
-func NewRegularSync(cfg *Config) *Service {
-	ctx, cancel := context.WithCancel(context.Background())
-	r := &Service{
-		ctx:                  ctx,
-		cancel:               cancel,
-		db:                   cfg.DB,
-		p2p:                  cfg.P2P,
-		attPool:              cfg.AttPool,
-		exitPool:             cfg.ExitPool,
-		slashingPool:         cfg.SlashingPool,
-		chain:                cfg.Chain,
-		initialSync:          cfg.InitialSync,
-		attestationNotifier:  cfg.AttestationNotifier,
-		slotToPendingBlocks:  make(map[uint64]*ethpb.SignedBeaconBlock),
-		seenPendingBlocks:    make(map[[32]byte]bool),
-		blkRootToPendingAtts: make(map[[32]byte][]*ethpb.SignedAggregateAttestationAndProof),
-		stateNotifier:        cfg.StateNotifier,
-		blockNotifier:        cfg.BlockNotifier,
-		stateSummaryCache:    cfg.StateSummaryCache,
-		stateGen:             cfg.StateGen,
-		blocksRateLimiter:    leakybucket.NewCollector(allowedBlocksPerSecond, allowedBlocksBurst, false /* deleteEmptyBuckets */),
-	}
-
-	r.registerRPCHandlers()
-	go r.registerSubscribers()
-
-	return r
-}
-
 // Service is responsible for handling all run time p2p related operations as the
 // main entry point for network messages.
 type Service struct {
@@ -129,6 +99,36 @@ type Service struct {
 	stateGen                  *stategen.State
 }
 
+// NewRegularSync service.
+func NewRegularSync(cfg *Config) *Service {
+	ctx, cancel := context.WithCancel(context.Background())
+	r := &Service{
+		ctx:                  ctx,
+		cancel:               cancel,
+		db:                   cfg.DB,
+		p2p:                  cfg.P2P,
+		attPool:              cfg.AttPool,
+		exitPool:             cfg.ExitPool,
+		slashingPool:         cfg.SlashingPool,
+		chain:                cfg.Chain,
+		initialSync:          cfg.InitialSync,
+		attestationNotifier:  cfg.AttestationNotifier,
+		slotToPendingBlocks:  make(map[uint64]*ethpb.SignedBeaconBlock),
+		seenPendingBlocks:    make(map[[32]byte]bool),
+		blkRootToPendingAtts: make(map[[32]byte][]*ethpb.SignedAggregateAttestationAndProof),
+		stateNotifier:        cfg.StateNotifier,
+		blockNotifier:        cfg.BlockNotifier,
+		stateSummaryCache:    cfg.StateSummaryCache,
+		stateGen:             cfg.StateGen,
+		blocksRateLimiter:    leakybucket.NewCollector(allowedBlocksPerSecond, allowedBlocksBurst, false /* deleteEmptyBuckets */),
+	}
+
+	r.registerRPCHandlers()
+	go r.registerSubscribers()
+
+	return r
+}
+
 // Start the regular sync service.
 func (r *Service) Start() {
 	if err := r.initCaches(); err != nil {