Fix slot chain dead lock bug and deprecated resource slot chain (#379)

Author: louyuting

api/api.go

@@ -18,7 +18,6 @@ import (
 	"sync"
 
 	"github.com/alibaba/sentinel-golang/core/base"
-	"github.com/alibaba/sentinel-golang/core/misc"
 )
 
 var entryOptsPool = sync.Pool{
@@ -142,10 +141,7 @@ func Entry(resource string, opts ...EntryOption) (*base.SentinelEntry, *base.Blo
 		opt(options)
 	}
 	if options.slotChain == nil {
-		options.slotChain = misc.GetResourceSlotChain(resource)
-		if options.slotChain == nil {
-			options.slotChain = GlobalSlotChain()
-		}
+		options.slotChain = GlobalSlotChain()
 	}
 	return entry(resource, options)
 }

api/api_test.go

@@ -26,10 +26,6 @@ type prepareSlotMock struct {
 	mock.Mock
 }
 
-func (m *prepareSlotMock) Name() string {
-	return "mock-sentinel-prepare-slot"
-}
-
 func (m *prepareSlotMock) Order() uint32 {
 	return 0
 }
@@ -43,10 +39,6 @@ type mockRuleCheckSlot1 struct {
 	mock.Mock
 }
 
-func (m *mockRuleCheckSlot1) Name() string {
-	return "mock-sentinel-rule-check-slot1"
-}
-
 func (m *mockRuleCheckSlot1) Order() uint32 {
 	return 0
 }
@@ -60,10 +52,6 @@ type mockRuleCheckSlot2 struct {
 	mock.Mock
 }
 
-func (m *mockRuleCheckSlot2) Name() string {
-	return "mock-sentinel-rule-check-slot2"
-}
-
 func (m *mockRuleCheckSlot2) Order() uint32 {
 	return 0
 }
@@ -77,10 +65,6 @@ type statisticSlotMock struct {
 	mock.Mock
 }
 
-func (m *statisticSlotMock) Name() string {
-	return "mock-sentinel-stat-check-slot"
-}
-
 func (m *statisticSlotMock) Order() uint32 {
 	return 0
 }

api/slot_chain.go

@@ -21,7 +21,6 @@ import (
 	"github.com/alibaba/sentinel-golang/core/hotspot"
 	"github.com/alibaba/sentinel-golang/core/isolation"
 	"github.com/alibaba/sentinel-golang/core/log"
-	"github.com/alibaba/sentinel-golang/core/misc"
 	"github.com/alibaba/sentinel-golang/core/stat"
 	"github.com/alibaba/sentinel-golang/core/system"
 )
@@ -49,21 +48,3 @@ func BuildDefaultSlotChain() *base.SlotChain {
 	sc.AddStatSlot(circuitbreaker.DefaultMetricStatSlot)
 	return sc
 }
-
-// RegisterGlobalStatPrepareSlot registers the global StatPrepareSlot for all resource
-// Note: this function is not thread-safe
-func RegisterGlobalStatPrepareSlot(slot base.StatPrepareSlot) {
-	misc.RegisterGlobalStatPrepareSlot(slot)
-}
-
-// RegisterGlobalRuleCheckSlot registers the global RuleCheckSlot for all resource
-// Note: this function is not thread-safe
-func RegisterGlobalRuleCheckSlot(slot base.RuleCheckSlot) {
-	misc.RegisterGlobalRuleCheckSlot(slot)
-}
-
-// RegisterGlobalStatSlot registers the global StatSlot for all resource
-// Note: this function is not thread-safe
-func RegisterGlobalStatSlot(slot base.StatSlot) {
-	misc.RegisterGlobalStatSlot(slot)
-}

core/base/slot_chain.go

@@ -24,9 +24,6 @@ import (
 )
 
 type BaseSlot interface {
-	// Name returns it's slot name which should be global unique.
-	Name() string
-
 	// Order returns the sort value of the slot.
 	// SlotChain will sort all it's slots by ascending sort value in each bucket
 	// (StatPrepareSlot bucket、RuleCheckSlot bucket and StatSlot bucket)
@@ -77,8 +74,6 @@ type StatSlot interface {
 // SlotChain hold all system slots and customized slot.
 // SlotChain support plug-in slots developed by developer.
 type SlotChain struct {
-	// RWMutex guard the slots in SlotChain and make sure the concurrency safe
-	sync.RWMutex
 	// statPres is in ascending order by StatPrepareSlot.Order() value.
 	statPres []StatPrepareSlot
 	// ruleChecks is in ascending order by RuleCheckSlot.Order() value.
@@ -108,7 +103,6 @@ var (
 
 func NewSlotChain() *SlotChain {
 	return &SlotChain{
-		RWMutex:    sync.RWMutex{},
 		statPres:   make([]StatPrepareSlot, 0, 8),
 		ruleChecks: make([]RuleCheckSlot, 0, 8),
 		stats:      make([]StatSlot, 0, 8),
@@ -130,31 +124,6 @@ func (sc *SlotChain) RefurbishContext(c *EntryContext) {
 	}
 }
 
-// ValidateStatPrepareSlotNaming checks whether the name of StatPrepareSlot exists in SlotChain.[]StatPrepareSlot
-// return true the name of StatPrepareSlot doesn't exist in SlotChain.[]StatPrepareSlot
-// ValidateStatPrepareSlotNaming is non-thread safe,
-// In concurrency scenario, ValidateStatPrepareSlotNaming must be guarded by SlotChain.RWMutex#RLock
-func ValidateStatPrepareSlotNaming(sc *SlotChain, s StatPrepareSlot) bool {
-	isValid := true
-	f := func(slot StatPrepareSlot) {
-		if slot.Name() == s.Name() {
-			isValid = false
-		}
-	}
-	sc.RangeStatPrepareSlot(f)
-
-	return isValid
-}
-
-// RangeStatPrepareSlot iterates the SlotChain.[]StatPrepareSlot and call f function for each StatPrepareSlot
-// RangeStatPrepareSlot is non-thread safe,
-// In concurrency scenario, RangeStatPrepareSlot must be guarded by SlotChain.RWMutex#RLock
-func (sc *SlotChain) RangeStatPrepareSlot(f func(slot StatPrepareSlot)) {
-	for _, slot := range sc.statPres {
-		f(slot)
-	}
-}
-
 // AddStatPrepareSlot adds the StatPrepareSlot slot to the StatPrepareSlot list of the SlotChain.
 // All StatPrepareSlot in the list will be sorted according to StatPrepareSlot.Order() in ascending order.
 // AddStatPrepareSlot is non-thread safe,
@@ -166,31 +135,6 @@ func (sc *SlotChain) AddStatPrepareSlot(s StatPrepareSlot) {
 	})
 }
 
-// ValidateRuleCheckSlotNaming checks whether the name of RuleCheckSlot exists in SlotChain.[]RuleCheckSlot
-// return true the name of RuleCheckSlot doesn't exist in SlotChain.[]RuleCheckSlot
-// ValidateRuleCheckSlotNaming is non-thread safe,
-// In concurrency scenario, ValidateRuleCheckSlotNaming must be guarded by SlotChain.RWMutex#RLock
-func ValidateRuleCheckSlotNaming(sc *SlotChain, s RuleCheckSlot) bool {
-	isValid := true
-	f := func(slot RuleCheckSlot) {
-		if slot.Name() == s.Name() {
-			isValid = false
-		}
-	}
-	sc.RangeRuleCheckSlot(f)
-
-	return isValid
-}
-
-// RangeRuleCheckSlot iterates the SlotChain.[]RuleCheckSlot and call f function for each RuleCheckSlot
-// RangeRuleCheckSlot is non-thread safe,
-// In concurrency scenario, RangeRuleCheckSlot must be guarded by SlotChain.RWMutex#RLock
-func (sc *SlotChain) RangeRuleCheckSlot(f func(slot RuleCheckSlot)) {
-	for _, slot := range sc.ruleChecks {
-		f(slot)
-	}
-}
-
 // AddRuleCheckSlot adds the RuleCheckSlot to the RuleCheckSlot list of the SlotChain.
 // All RuleCheckSlot in the list will be sorted according to RuleCheckSlot.Order() in ascending order.
 // AddRuleCheckSlot is non-thread safe,
@@ -202,31 +146,6 @@ func (sc *SlotChain) AddRuleCheckSlot(s RuleCheckSlot) {
 	})
 }
 
-// ValidateStatSlotNaming checks whether the name of StatSlot exists in SlotChain.[]StatSlot
-// return true the name of StatSlot doesn't exist in SlotChain.[]StatSlot
-// ValidateStatSlotNaming is non-thread safe,
-// In concurrency scenario, ValidateStatSlotNaming must be guarded by SlotChain.RWMutex#RLock
-func ValidateStatSlotNaming(sc *SlotChain, s StatSlot) bool {
-	isValid := true
-	f := func(slot StatSlot) {
-		if slot.Name() == s.Name() {
-			isValid = false
-		}
-	}
-	sc.RangeStatSlot(f)
-
-	return isValid
-}
-
-// RangeStatSlot iterates the SlotChain.[]StatSlot and call f function for each StatSlot
-// RangeStatSlot is non-thread safe,
-// In concurrency scenario, RangeStatSlot must be guarded by SlotChain.RWMutex#RLock
-func (sc *SlotChain) RangeStatSlot(f func(slot StatSlot)) {
-	for _, slot := range sc.stats {
-		f(slot)
-	}
-}
-
 // AddStatSlot adds the StatSlot to the StatSlot list of the SlotChain.
 // All StatSlot in the list will be sorted according to StatSlot.Order() in ascending order.
 // AddStatSlot is non-thread safe,
@@ -241,11 +160,9 @@ func (sc *SlotChain) AddStatSlot(s StatSlot) {
 // The entrance of slot chain
 // Return the TokenResult and nil if internal panic.
 func (sc *SlotChain) Entry(ctx *EntryContext) *TokenResult {
-	sc.RLock()
 	// This should not happen, unless there are errors existing in Sentinel internal.
 	// If happened, need to add TokenResult in EntryContext
 	defer func() {
-		sc.RUnlock()
 		if err := recover(); err != nil {
 			logging.Error(errors.Errorf("%+v", err), "Sentinel internal panic in SlotChain.Entry()")
 			ctx.SetError(errors.Errorf("%+v", err))
@@ -311,9 +228,6 @@ func (sc *SlotChain) exit(ctx *EntryContext) {
 	if ctx.IsBlocked() {
 		return
 	}
-
-	sc.RLock()
-	defer sc.RUnlock()
 	for _, s := range sc.stats {
 		s.OnCompleted(ctx)
 	}