server: Refactor compaction checker

Signed-off-by: Marek Siarkowicz <siarkowicz@google.com>

server/embed/etcd.go

@@ -248,7 +248,7 @@ func StartEtcd(inCfg *Config) (e *Etcd, err error) {
 	// newly started member ("memberInitialized==false")
 	// does not need corruption check
 	if memberInitialized && srvcfg.InitialCorruptCheck {
-		if err = etcdserver.NewCorruptionMonitor(e.cfg.logger, e.Server).InitialCheck(); err != nil {
+		if err = e.Server.CorruptionChecker().InitialCheck(); err != nil {
 			// set "EtcdServer" to nil, so that it does not block on "EtcdServer.Close()"
 			// (nothing to close since rafthttp transports have not been started)
 

server/etcdserver/corrupt.go

@@ -33,7 +33,12 @@ import (
 	"go.uber.org/zap"
 )
 
-type corruptionMonitor struct {
+type CorruptionChecker interface {
+	InitialCheck() error
+	PeriodicCheck() error
+}
+
+type corruptionChecker struct {
 	lg *zap.Logger
 
 	hasher Hasher
@@ -48,8 +53,8 @@ type Hasher interface {
 	TriggerCorruptAlarm(uint64)
 }
 
-func NewCorruptionMonitor(lg *zap.Logger, s *EtcdServer) *corruptionMonitor {
+func NewCorruptionChecker(lg *zap.Logger, s *EtcdServer) *corruptionChecker {
-	return &corruptionMonitor{
+	return &corruptionChecker{
 		lg:     lg,
 		hasher: hasherAdapter{s, s.KV().HashStorage()},
 	}
@@ -79,7 +84,7 @@ func (h hasherAdapter) TriggerCorruptAlarm(memberID uint64) {
 // InitialCheck compares initial hash values with its peers
 // before serving any peer/client traffic. Only mismatch when hashes
 // are different at requested revision, with same compact revision.
-func (cm *corruptionMonitor) InitialCheck() error {
+func (cm *corruptionChecker) InitialCheck() error {
 
 	cm.lg.Info(
 		"starting initial corruption check",
@@ -158,7 +163,7 @@ func (cm *corruptionMonitor) InitialCheck() error {
 	return nil
 }
 
-func (cm *corruptionMonitor) periodicCheck() error {
+func (cm *corruptionChecker) PeriodicCheck() error {
 	h, rev, err := cm.hasher.HashByRev(0)
 	if err != nil {
 		return err

server/etcdserver/corrupt_test.go

@@ -88,7 +88,7 @@ func TestInitialCheck(t *testing.T) {
 	}
 	for _, tc := range tcs {
 		t.Run(tc.name, func(t *testing.T) {
-			monitor := corruptionMonitor{
+			monitor := corruptionChecker{
 				lg:     zaptest.NewLogger(t),
 				hasher: &tc.hasher,
 			}
@@ -205,11 +205,11 @@ func TestPeriodicCheck(t *testing.T) {
 	}
 	for _, tc := range tcs {
 		t.Run(tc.name, func(t *testing.T) {
-			monitor := corruptionMonitor{
+			monitor := corruptionChecker{
 				lg:     zaptest.NewLogger(t),
 				hasher: &tc.hasher,
 			}
-			err := monitor.periodicCheck()
+			err := monitor.PeriodicCheck()
 			if gotError := err != nil; gotError != tc.expectError {
 				t.Errorf("Unexpected error, got: %v, expected?: %v", err, tc.expectError)
 			}

server/etcdserver/server.go

@@ -293,6 +293,7 @@ type EtcdServer struct {
 	firstCommitInTermC  chan struct{}
 
 	*AccessController
+	corruptionChecker CorruptionChecker
 }
 
 type backendHooks struct {
@@ -629,6 +630,7 @@ func NewServer(cfg config.ServerConfig) (srv *EtcdServer, err error) {
 			)
 		}
 	}
+	srv.corruptionChecker = NewCorruptionChecker(cfg.Logger, srv)
 
 	srv.authStore = auth.NewAuthStore(srv.Logger(), srv.be, tp, int(cfg.BcryptCost))
 
@@ -2520,7 +2522,6 @@ func (s *EtcdServer) monitorKVHash() {
 		zap.String("local-member-id", s.ID().String()),
 		zap.Duration("interval", t),
 	)
-	monitor := NewCorruptionMonitor(lg, s)
 	for {
 		select {
 		case <-s.stopping:
@@ -2530,7 +2531,7 @@ func (s *EtcdServer) monitorKVHash() {
 		if !s.isLeader() {
 			continue
 		}
-		if err := monitor.periodicCheck(); err != nil {
+		if err := s.corruptionChecker.PeriodicCheck(); err != nil {
 			lg.Warn("failed to check hash KV", zap.Error(err))
 		}
 	}
@@ -2773,3 +2774,7 @@ func maybeDefragBackend(cfg config.ServerConfig, be backend.Backend) error {
 	}
 	return be.Defrag()
 }
+
+func (s *EtcdServer) CorruptionChecker() CorruptionChecker {
+	return s.corruptionChecker
+}