get the value but not update the expiration time

go.mod

@@ -18,7 +18,6 @@ require (
 	github.com/jinzhu/now v1.1.5 // indirect
 	github.com/jroimartin/gocui v0.4.0
 	github.com/kardianos/service v1.2.1
-	github.com/muesli/cache2go v0.0.0-20200423001931-a100c5aac93f
 	github.com/nicksnyder/go-i18n/v2 v2.0.3
 	github.com/nsqio/go-nsq v1.0.8
 	github.com/olivere/elastic v6.2.31+incompatible

go.sum

@@ -144,7 +144,6 @@ github.com/mattn/go-sqlite3 v2.0.1+incompatible/go.mod h1:FPy6KqzDD04eiIsT53CuJW
 github.com/matttproud/golang_protobuf_extensions v1.0.1/go.mod h1:D8He9yQNgCq6Z5Ld7szi9bcBfOoFv/3dc6xSMkL2PC0=
 github.com/mitchellh/go-homedir v1.1.0/go.mod h1:SfyaCUpYCn1Vlf4IUYiD9fPX4A5wJrkLzIz1N1q0pr0=
 github.com/mitchellh/mapstructure v1.1.2/go.mod h1:FVVH3fgwuzCH5S8UJGiWEs2h04kUh9fWfEaFds41c1Y=
-github.com/muesli/cache2go v0.0.0-20200423001931-a100c5aac93f h1:dBzTzAKOh89fTvdQ3XlXupMExvLty90V1rrpChTAQAY=
 github.com/muesli/cache2go v0.0.0-20200423001931-a100c5aac93f/go.mod h1:414R+qZrt4f9S2TO/s6YVQMNAXR2KdwqQ7pW+O4oYzU=
 github.com/mwitkow/go-conntrack v0.0.0-20161129095857-cc309e4a2223/go.mod h1:qRWi+5nqEBWmkhHvq77mSJWrCKwh8bxhgT7d/eI7P4U=
 github.com/nicksnyder/go-i18n/v2 v2.0.3 h1:ks/JkQiOEhhuF6jpNvx+Wih1NIiXzUnZeZVnJuI8R8M=

mycache/cache2go/benchmark_test.go

@@ -0,0 +1,49 @@
+/*
+ * Simple caching library with expiration capabilities
+ *     Copyright (c) 2013-2017, Christian Muehlhaeuser <muesli@gmail.com>
+ *
+ *   For license see LICENSE.txt
+ */
+
+package cache2go
+
+import (
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+)
+
+func BenchmarkNotFoundAdd(b *testing.B) {
+	table := Cache("testNotFoundAdd")
+
+	var finish sync.WaitGroup
+	var added int32
+	var idle int32
+
+	fn := func(id int) {
+		for i := 0; i < b.N; i++ {
+			if table.NotFoundAdd(i, 0, i+id) {
+				atomic.AddInt32(&added, 1)
+			} else {
+				atomic.AddInt32(&idle, 1)
+			}
+			time.Sleep(0)
+		}
+		finish.Done()
+	}
+
+	finish.Add(10)
+	go fn(0x0000)
+	go fn(0x1100)
+	go fn(0x2200)
+	go fn(0x3300)
+	go fn(0x4400)
+	go fn(0x5500)
+	go fn(0x6600)
+	go fn(0x7700)
+	go fn(0x8800)
+	go fn(0x9900)
+	finish.Wait()
+
+}

mycache/cache2go/cache.go

@@ -0,0 +1,42 @@
+/*
+ * Simple caching library with expiration capabilities
+ *     Copyright (c) 2012, Radu Ioan Fericean
+ *                   2013-2017, Christian Muehlhaeuser <muesli@gmail.com>
+ *
+ *   For license see LICENSE.txt
+ */
+
+package cache2go
+
+import (
+	"sync"
+)
+
+var (
+	cache = make(map[string]*CacheTable)
+	mutex sync.RWMutex
+)
+
+// Cache returns the existing cache table with given name or creates a new one
+// if the table does not exist yet.
+func Cache(table string) *CacheTable {
+	mutex.RLock()
+	t, ok := cache[table]
+	mutex.RUnlock()
+
+	if !ok {
+		mutex.Lock()
+		t, ok = cache[table]
+		// Double check whether the table exists or not.
+		if !ok {
+			t = &CacheTable{
+				name:  table,
+				items: make(map[interface{}]*CacheItem),
+			}
+			cache[table] = t
+		}
+		mutex.Unlock()
+	}
+
+	return t
+}

mycache/cache2go/cache_test.go

@@ -0,0 +1,517 @@
+/*
+ * Simple caching library with expiration capabilities
+ *     Copyright (c) 2013-2017, Christian Muehlhaeuser <muesli@gmail.com>
+ *
+ *   For license see LICENSE.txt
+ */
+
+package cache2go
+
+import (
+	"bytes"
+	"log"
+	"strconv"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+)
+
+var (
+	k = "testkey"
+	v = "testvalue"
+)
+
+func TestCache(t *testing.T) {
+	// add an expiring item after a non-expiring one to
+	// trigger expirationCheck iterating over non-expiring items
+	table := Cache("testCache")
+	table.Add(k+"_1", 0*time.Second, v)
+	table.Add(k+"_2", 1*time.Second, v)
+
+	// check if both items are still there
+	p, err := table.Value(k + "_1")
+	if err != nil || p == nil || p.Data().(string) != v {
+		t.Error("Error retrieving non expiring data from cache", err)
+	}
+	p, err = table.Value(k + "_2")
+	if err != nil || p == nil || p.Data().(string) != v {
+		t.Error("Error retrieving data from cache", err)
+	}
+
+	// sanity checks
+	if p.AccessCount() != 1 {
+		t.Error("Error getting correct access count")
+	}
+	if p.LifeSpan() != 1*time.Second {
+		t.Error("Error getting correct life-span")
+	}
+	if p.AccessedOn().Unix() == 0 {
+		t.Error("Error getting access time")
+	}
+	if p.CreatedOn().Unix() == 0 {
+		t.Error("Error getting creation time")
+	}
+}
+
+func TestCacheExpire(t *testing.T) {
+	table := Cache("testCache")
+
+	table.Add(k+"_1", 250*time.Millisecond, v+"_1")
+	table.Add(k+"_2", 200*time.Millisecond, v+"_2")
+
+	time.Sleep(100 * time.Millisecond)
+
+	// check key `1` is still alive
+	_, err := table.Value(k + "_1")
+	if err != nil {
+		t.Error("Error retrieving value from cache:", err)
+	}
+
+	time.Sleep(150 * time.Millisecond)
+
+	// check key `1` again, it should still be alive since we just accessed it
+	_, err = table.Value(k + "_1")
+	if err != nil {
+		t.Error("Error retrieving value from cache:", err)
+	}
+
+	// check key `2`, it should have been removed by now
+	_, err = table.Value(k + "_2")
+	if err == nil {
+		t.Error("Found key which should have been expired by now")
+	}
+}
+
+func TestExists(t *testing.T) {
+	// add an expiring item
+	table := Cache("testExists")
+	table.Add(k, 0, v)
+	// check if it exists
+	if !table.Exists(k) {
+		t.Error("Error verifying existing data in cache")
+	}
+}
+
+func TestNotFoundAdd(t *testing.T) {
+	table := Cache("testNotFoundAdd")
+
+	if !table.NotFoundAdd(k, 0, v) {
+		t.Error("Error verifying NotFoundAdd, data not in cache")
+	}
+
+	if table.NotFoundAdd(k, 0, v) {
+		t.Error("Error verifying NotFoundAdd data in cache")
+	}
+}
+
+func TestNotFoundAddConcurrency(t *testing.T) {
+	table := Cache("testNotFoundAdd")
+
+	var finish sync.WaitGroup
+	var added int32
+	var idle int32
+
+	fn := func(id int) {
+		for i := 0; i < 100; i++ {
+			if table.NotFoundAdd(i, 0, i+id) {
+				atomic.AddInt32(&added, 1)
+			} else {
+				atomic.AddInt32(&idle, 1)
+			}
+			time.Sleep(0)
+		}
+		finish.Done()
+	}
+
+	finish.Add(10)
+	go fn(0x0000)
+	go fn(0x1100)
+	go fn(0x2200)
+	go fn(0x3300)
+	go fn(0x4400)
+	go fn(0x5500)
+	go fn(0x6600)
+	go fn(0x7700)
+	go fn(0x8800)
+	go fn(0x9900)
+	finish.Wait()
+
+	t.Log(added, idle)
+
+	table.Foreach(func(key interface{}, item *CacheItem) {
+		v, _ := item.Data().(int)
+		k, _ := key.(int)
+		t.Logf("%02x  %04x\n", k, v)
+	})
+}
+
+func TestCacheKeepAlive(t *testing.T) {
+	// add an expiring item
+	table := Cache("testKeepAlive")
+	p := table.Add(k, 250*time.Millisecond, v)
+
+	// keep it alive before it expires
+	time.Sleep(100 * time.Millisecond)
+	p.KeepAlive()
+
+	// check it's still alive after it was initially supposed to expire
+	time.Sleep(150 * time.Millisecond)
+	if !table.Exists(k) {
+		t.Error("Error keeping item alive")
+	}
+
+	// check it expires eventually
+	time.Sleep(300 * time.Millisecond)
+	if table.Exists(k) {
+		t.Error("Error expiring item after keeping it alive")
+	}
+}
+
+func TestPeek(t *testing.T) {
+	// add an expiring item
+	table := Cache("TestPeek")
+	_ = table.Add(k, 250*time.Millisecond, v)
+	_ = table.Add(k+"_", 250*time.Millisecond, v)
+
+	// test peek item
+	time.Sleep(150 * time.Millisecond)
+	p, _ := table.Peek(k)
+	if p.Data() != v {
+		t.Error("Error peek item")
+	}
+
+	// test k is expired
+	time.Sleep(150 * time.Millisecond)
+	if table.Exists(k) {
+		t.Error("Error peek but expired time updated")
+	}
+
+	// test peek nil
+	_, err := table.Peek(k)
+	if err != ErrKeyNotFound {
+		t.Error("Error peek nil value but not return ErrKeyNotFound")
+	}
+
+	// test DataLoader
+	table.SetDataLoader(func(key interface{}, args ...interface{}) *CacheItem {
+		if key == k {
+			return NewCacheItem(key, 150*time.Millisecond, "new value")
+		}
+		return nil
+	})
+	p, _ = table.Peek(k)
+	if p.Data() != "new value" {
+		t.Error("Error peek DataLoader callback did not take effect")
+	}
+
+	_, err = table.Peek(k + "_")
+	if err != ErrKeyNotFoundOrLoadable {
+		t.Error("Error peek DataLoader err")
+	}
+}
+
+func TestDelete(t *testing.T) {
+	// add an item to the cache
+	table := Cache("testDelete")
+	table.Add(k, 0, v)
+	// check it's really cached
+	p, err := table.Value(k)
+	if err != nil || p == nil || p.Data().(string) != v {
+		t.Error("Error retrieving data from cache", err)
+	}
+	// try to delete it
+	table.Delete(k)
+	// verify it has been deleted
+	p, err = table.Value(k)
+	if err == nil || p != nil {
+		t.Error("Error deleting data")
+	}
+
+	// test error handling
+	_, err = table.Delete(k)
+	if err == nil {
+		t.Error("Expected error deleting item")
+	}
+}
+
+func TestFlush(t *testing.T) {
+	// add an item to the cache
+	table := Cache("testFlush")
+	table.Add(k, 10*time.Second, v)
+	// flush the entire table
+	table.Flush()
+
+	// try to retrieve the item
+	p, err := table.Value(k)
+	if err == nil || p != nil {
+		t.Error("Error flushing table")
+	}
+	// make sure there's really nothing else left in the cache
+	if table.Count() != 0 {
+		t.Error("Error verifying count of flushed table")
+	}
+}
+
+func TestCount(t *testing.T) {
+	// add a huge amount of items to the cache
+	table := Cache("testCount")
+	count := 100000
+	for i := 0; i < count; i++ {
+		key := k + strconv.Itoa(i)
+		table.Add(key, 10*time.Second, v)
+	}
+	// confirm every single item has been cached
+	for i := 0; i < count; i++ {
+		key := k + strconv.Itoa(i)
+		p, err := table.Value(key)
+		if err != nil || p == nil || p.Data().(string) != v {
+			t.Error("Error retrieving data")
+		}
+	}
+	// make sure the item count matches (no dupes etc.)
+	if table.Count() != count {
+		t.Error("Data count mismatch")
+	}
+}
+
+func TestDataLoader(t *testing.T) {
+	// setup a cache with a configured data-loader
+	table := Cache("testDataLoader")
+	table.SetDataLoader(func(key interface{}, args ...interface{}) *CacheItem {
+		var item *CacheItem
+		if key.(string) != "nil" {
+			val := k + key.(string)
+			i := NewCacheItem(key, 500*time.Millisecond, val)
+			item = i
+		}
+
+		return item
+	})
+
+	// make sure data-loader works as expected and handles unloadable keys
+	_, err := table.Value("nil")
+	if err == nil || table.Exists("nil") {
+		t.Error("Error validating data loader for nil values")
+	}
+
+	// retrieve a bunch of items via the data-loader
+	for i := 0; i < 10; i++ {
+		key := k + strconv.Itoa(i)
+		vp := k + key
+		p, err := table.Value(key)
+		if err != nil || p == nil || p.Data().(string) != vp {
+			t.Error("Error validating data loader")
+		}
+	}
+}
+
+func TestAccessCount(t *testing.T) {
+	// add 100 items to the cache
+	count := 100
+	table := Cache("testAccessCount")
+	for i := 0; i < count; i++ {
+		table.Add(i, 10*time.Second, v)
+	}
+	// never access the first item, access the second item once, the third
+	// twice and so on...
+	for i := 0; i < count; i++ {
+		for j := 0; j < i; j++ {
+			table.Value(i)
+		}
+	}
+
+	// check MostAccessed returns the items in correct order
+	ma := table.MostAccessed(int64(count))
+	for i, item := range ma {
+		if item.Key() != count-1-i {
+			t.Error("Most accessed items seem to be sorted incorrectly")
+		}
+	}
+
+	// check MostAccessed returns the correct amount of items
+	ma = table.MostAccessed(int64(count - 1))
+	if len(ma) != count-1 {
+		t.Error("MostAccessed returns incorrect amount of items")
+	}
+}
+
+func TestCallbacks(t *testing.T) {
+	var m sync.Mutex
+	addedKey := ""
+	removedKey := ""
+	calledAddedItem := false
+	calledRemoveItem := false
+	expired := false
+	calledExpired := false
+
+	// setup a cache with AddedItem & SetAboutToDelete handlers configured
+	table := Cache("testCallbacks")
+	table.SetAddedItemCallback(func(item *CacheItem) {
+		m.Lock()
+		addedKey = item.Key().(string)
+		m.Unlock()
+	})
+	table.SetAddedItemCallback(func(item *CacheItem) {
+		m.Lock()
+		calledAddedItem = true
+		m.Unlock()
+	})
+	table.SetAboutToDeleteItemCallback(func(item *CacheItem) {
+		m.Lock()
+		removedKey = item.Key().(string)
+		m.Unlock()
+	})
+
+	table.SetAboutToDeleteItemCallback(func(item *CacheItem) {
+		m.Lock()
+		calledRemoveItem = true
+		m.Unlock()
+	})
+	// add an item to the cache and setup its AboutToExpire handler
+	i := table.Add(k, 500*time.Millisecond, v)
+	i.SetAboutToExpireCallback(func(key interface{}) {
+		m.Lock()
+		expired = true
+		m.Unlock()
+	})
+
+	i.SetAboutToExpireCallback(func(key interface{}) {
+		m.Lock()
+		calledExpired = true
+		m.Unlock()
+	})
+
+	// verify the AddedItem handler works
+	time.Sleep(250 * time.Millisecond)
+	m.Lock()
+	if addedKey == k && !calledAddedItem {
+		t.Error("AddedItem callback not working")
+	}
+	m.Unlock()
+	// verify the AboutToDelete handler works
+	time.Sleep(500 * time.Millisecond)
+	m.Lock()
+	if removedKey == k && !calledRemoveItem {
+		t.Error("AboutToDeleteItem callback not working:" + k + "_" + removedKey)
+	}
+	// verify the AboutToExpire handler works
+	if expired && !calledExpired {
+		t.Error("AboutToExpire callback not working")
+	}
+	m.Unlock()
+
+}
+
+func TestCallbackQueue(t *testing.T) {
+	var m sync.Mutex
+	addedKey := ""
+	addedkeyCallback2 := ""
+	secondCallbackResult := "second"
+	removedKey := ""
+	removedKeyCallback := ""
+	expired := false
+	calledExpired := false
+	// setup a cache with AddedItem & SetAboutToDelete handlers configured
+	table := Cache("testCallbacks")
+
+	// test callback queue
+	table.AddAddedItemCallback(func(item *CacheItem) {
+		m.Lock()
+		addedKey = item.Key().(string)
+		m.Unlock()
+	})
+	table.AddAddedItemCallback(func(item *CacheItem) {
+		m.Lock()
+		addedkeyCallback2 = secondCallbackResult
+		m.Unlock()
+	})
+
+	table.AddAboutToDeleteItemCallback(func(item *CacheItem) {
+		m.Lock()
+		removedKey = item.Key().(string)
+		m.Unlock()
+	})
+	table.AddAboutToDeleteItemCallback(func(item *CacheItem) {
+		m.Lock()
+		removedKeyCallback = secondCallbackResult
+		m.Unlock()
+	})
+
+	i := table.Add(k, 500*time.Millisecond, v)
+	i.AddAboutToExpireCallback(func(key interface{}) {
+		m.Lock()
+		expired = true
+		m.Unlock()
+	})
+	i.AddAboutToExpireCallback(func(key interface{}) {
+		m.Lock()
+		calledExpired = true
+		m.Unlock()
+	})
+
+	time.Sleep(250 * time.Millisecond)
+	m.Lock()
+	if addedKey != k && addedkeyCallback2 != secondCallbackResult {
+		t.Error("AddedItem callback queue not working")
+	}
+	m.Unlock()
+
+	time.Sleep(500 * time.Millisecond)
+	m.Lock()
+	if removedKey != k && removedKeyCallback != secondCallbackResult {
+		t.Error("Item removed callback queue not working")
+	}
+	m.Unlock()
+
+	// test removing of the callbacks
+	table.RemoveAddedItemCallbacks()
+	table.RemoveAboutToDeleteItemCallback()
+	secondItemKey := "itemKey02"
+	expired = false
+	i = table.Add(secondItemKey, 500*time.Millisecond, v)
+	i.SetAboutToExpireCallback(func(key interface{}) {
+		m.Lock()
+		expired = true
+		m.Unlock()
+	})
+	i.RemoveAboutToExpireCallback()
+
+	// verify if the callbacks were removed
+	time.Sleep(250 * time.Millisecond)
+	m.Lock()
+	if addedKey == secondItemKey {
+		t.Error("AddedItemCallbacks were not removed")
+	}
+	m.Unlock()
+
+	// verify the AboutToDelete handler works
+	time.Sleep(500 * time.Millisecond)
+	m.Lock()
+	if removedKey == secondItemKey {
+		t.Error("AboutToDeleteItem not removed")
+	}
+	// verify the AboutToExpire handler works
+	if !expired && !calledExpired {
+		t.Error("AboutToExpire callback not working")
+	}
+	m.Unlock()
+}
+
+func TestLogger(t *testing.T) {
+	// setup a logger
+	out := new(bytes.Buffer)
+	l := log.New(out, "cache2go ", log.Ldate|log.Ltime)
+
+	// setup a cache with this logger
+	table := Cache("testLogger")
+	table.SetLogger(l)
+	table.Add(k, 0, v)
+
+	time.Sleep(100 * time.Millisecond)
+
+	// verify the logger has been used
+	if out.Len() == 0 {
+		t.Error("Logger is empty")
+	}
+}

mycache/cache2go/cacheitem.go

@@ -0,0 +1,132 @@
+/*
+ * Simple caching library with expiration capabilities
+ *     Copyright (c) 2013-2017, Christian Muehlhaeuser <muesli@gmail.com>
+ *
+ *   For license see LICENSE.txt
+ */
+
+package cache2go
+
+import (
+	"sync"
+	"time"
+)
+
+// CacheItem is an individual cache item
+// Parameter data contains the user-set value in the cache.
+type CacheItem struct {
+	sync.RWMutex
+
+	// The item's key.
+	key interface{}
+	// The item's data.
+	data interface{}
+	// How long will the item live in the cache when not being accessed/kept alive.
+	lifeSpan time.Duration
+
+	// Creation timestamp.
+	createdOn time.Time
+	// Last access timestamp.
+	accessedOn time.Time
+	// How often the item was accessed.
+	accessCount int64
+
+	// Callback method triggered right before removing the item from the cache
+	aboutToExpire []func(key interface{})
+}
+
+// NewCacheItem returns a newly created CacheItem.
+// Parameter key is the item's cache-key.
+// Parameter lifeSpan determines after which time period without an access the item
+// will get removed from the cache.
+// Parameter data is the item's value.
+func NewCacheItem(key interface{}, lifeSpan time.Duration, data interface{}) *CacheItem {
+	t := time.Now()
+	return &CacheItem{
+		key:           key,
+		lifeSpan:      lifeSpan,
+		createdOn:     t,
+		accessedOn:    t,
+		accessCount:   0,
+		aboutToExpire: nil,
+		data:          data,
+	}
+}
+
+// AddAccessCount only add one access count.
+func (item *CacheItem) AddAccessCount() {
+	item.Lock()
+	defer item.Unlock()
+	item.accessCount++
+}
+
+// KeepAlive marks an item to be kept for another expireDuration period.
+func (item *CacheItem) KeepAlive() {
+	item.Lock()
+	defer item.Unlock()
+	item.accessedOn = time.Now()
+	item.accessCount++
+}
+
+// LifeSpan returns this item's expiration duration.
+func (item *CacheItem) LifeSpan() time.Duration {
+	// immutable
+	return item.lifeSpan
+}
+
+// AccessedOn returns when this item was last accessed.
+func (item *CacheItem) AccessedOn() time.Time {
+	item.RLock()
+	defer item.RUnlock()
+	return item.accessedOn
+}
+
+// CreatedOn returns when this item was added to the cache.
+func (item *CacheItem) CreatedOn() time.Time {
+	// immutable
+	return item.createdOn
+}
+
+// AccessCount returns how often this item has been accessed.
+func (item *CacheItem) AccessCount() int64 {
+	item.RLock()
+	defer item.RUnlock()
+	return item.accessCount
+}
+
+// Key returns the key of this cached item.
+func (item *CacheItem) Key() interface{} {
+	// immutable
+	return item.key
+}
+
+// Data returns the value of this cached item.
+func (item *CacheItem) Data() interface{} {
+	// immutable
+	return item.data
+}
+
+// SetAboutToExpireCallback configures a callback, which will be called right
+// before the item is about to be removed from the cache.
+func (item *CacheItem) SetAboutToExpireCallback(f func(interface{})) {
+	if len(item.aboutToExpire) > 0 {
+		item.RemoveAboutToExpireCallback()
+	}
+	item.Lock()
+	defer item.Unlock()
+	item.aboutToExpire = append(item.aboutToExpire, f)
+}
+
+// AddAboutToExpireCallback appends a new callback to the AboutToExpire queue
+func (item *CacheItem) AddAboutToExpireCallback(f func(interface{})) {
+	item.Lock()
+	defer item.Unlock()
+	item.aboutToExpire = append(item.aboutToExpire, f)
+}
+
+// RemoveAboutToExpireCallback empties the about to expire callback queue
+func (item *CacheItem) RemoveAboutToExpireCallback() {
+	item.Lock()
+	defer item.Unlock()
+	item.aboutToExpire = nil
+}

mycache/cache2go/cachetable.go

@@ -0,0 +1,398 @@
+/*
+ * Simple caching library with expiration capabilities
+ *     Copyright (c) 2013-2017, Christian Muehlhaeuser <muesli@gmail.com>
+ *
+ *   For license see LICENSE.txt
+ */
+
+package cache2go
+
+import (
+	"log"
+	"sort"
+	"sync"
+	"time"
+)
+
+// CacheTable is a table within the cache
+type CacheTable struct {
+	sync.RWMutex
+
+	// The table's name.
+	name string
+	// All cached items.
+	items map[interface{}]*CacheItem
+
+	// Timer responsible for triggering cleanup.
+	cleanupTimer *time.Timer
+	// Current timer duration.
+	cleanupInterval time.Duration
+
+	// The logger used for this table.
+	logger *log.Logger
+
+	// Callback method triggered when trying to load a non-existing key.
+	loadData func(key interface{}, args ...interface{}) *CacheItem
+	// Callback method triggered when adding a new item to the cache.
+	addedItem []func(item *CacheItem)
+	// Callback method triggered before deleting an item from the cache.
+	aboutToDeleteItem []func(item *CacheItem)
+}
+
+// Count returns how many items are currently stored in the cache.
+func (table *CacheTable) Count() int {
+	table.RLock()
+	defer table.RUnlock()
+	return len(table.items)
+}
+
+// Foreach all items
+func (table *CacheTable) Foreach(trans func(key interface{}, item *CacheItem)) {
+	table.RLock()
+	defer table.RUnlock()
+
+	for k, v := range table.items {
+		trans(k, v)
+	}
+}
+
+// SetDataLoader configures a data-loader callback, which will be called when
+// trying to access a non-existing key. The key and 0...n additional arguments
+// are passed to the callback function.
+func (table *CacheTable) SetDataLoader(f func(interface{}, ...interface{}) *CacheItem) {
+	table.Lock()
+	defer table.Unlock()
+	table.loadData = f
+}
+
+// SetAddedItemCallback configures a callback, which will be called every time
+// a new item is added to the cache.
+func (table *CacheTable) SetAddedItemCallback(f func(*CacheItem)) {
+	if len(table.addedItem) > 0 {
+		table.RemoveAddedItemCallbacks()
+	}
+	table.Lock()
+	defer table.Unlock()
+	table.addedItem = append(table.addedItem, f)
+}
+
+// AddAddedItemCallback appends a new callback to the addedItem queue
+func (table *CacheTable) AddAddedItemCallback(f func(*CacheItem)) {
+	table.Lock()
+	defer table.Unlock()
+	table.addedItem = append(table.addedItem, f)
+}
+
+// RemoveAddedItemCallbacks empties the added item callback queue
+func (table *CacheTable) RemoveAddedItemCallbacks() {
+	table.Lock()
+	defer table.Unlock()
+	table.addedItem = nil
+}
+
+// SetAboutToDeleteItemCallback configures a callback, which will be called
+// every time an item is about to be removed from the cache.
+func (table *CacheTable) SetAboutToDeleteItemCallback(f func(*CacheItem)) {
+	if len(table.aboutToDeleteItem) > 0 {
+		table.RemoveAboutToDeleteItemCallback()
+	}
+	table.Lock()
+	defer table.Unlock()
+	table.aboutToDeleteItem = append(table.aboutToDeleteItem, f)
+}
+
+// AddAboutToDeleteItemCallback appends a new callback to the AboutToDeleteItem queue
+func (table *CacheTable) AddAboutToDeleteItemCallback(f func(*CacheItem)) {
+	table.Lock()
+	defer table.Unlock()
+	table.aboutToDeleteItem = append(table.aboutToDeleteItem, f)
+}
+
+// RemoveAboutToDeleteItemCallback empties the about to delete item callback queue
+func (table *CacheTable) RemoveAboutToDeleteItemCallback() {
+	table.Lock()
+	defer table.Unlock()
+	table.aboutToDeleteItem = nil
+}
+
+// SetLogger sets the logger to be used by this cache table.
+func (table *CacheTable) SetLogger(logger *log.Logger) {
+	table.Lock()
+	defer table.Unlock()
+	table.logger = logger
+}
+
+// Expiration check loop, triggered by a self-adjusting timer.
+func (table *CacheTable) expirationCheck() {
+	table.Lock()
+	if table.cleanupTimer != nil {
+		table.cleanupTimer.Stop()
+	}
+	if table.cleanupInterval > 0 {
+		table.log("Expiration check triggered after", table.cleanupInterval, "for table", table.name)
+	} else {
+		table.log("Expiration check installed for table", table.name)
+	}
+
+	// To be more accurate with timers, we would need to update 'now' on every
+	// loop iteration. Not sure it's really efficient though.
+	now := time.Now()
+	smallestDuration := 0 * time.Second
+	for key, item := range table.items {
+		// Cache values so we don't keep blocking the mutex.
+		item.RLock()
+		lifeSpan := item.lifeSpan
+		accessedOn := item.accessedOn
+		item.RUnlock()
+
+		if lifeSpan == 0 {
+			continue
+		}
+		if now.Sub(accessedOn) >= lifeSpan {
+			// Item has excessed its lifespan.
+			table.deleteInternal(key)
+		} else {
+			// Find the item chronologically closest to its end-of-lifespan.
+			if smallestDuration == 0 || lifeSpan-now.Sub(accessedOn) < smallestDuration {
+				smallestDuration = lifeSpan - now.Sub(accessedOn)
+			}
+		}
+	}
+
+	// Setup the interval for the next cleanup run.
+	table.cleanupInterval = smallestDuration
+	if smallestDuration > 0 {
+		table.cleanupTimer = time.AfterFunc(smallestDuration, func() {
+			go table.expirationCheck()
+		})
+	}
+	table.Unlock()
+}
+
+func (table *CacheTable) addInternal(item *CacheItem) {
+	// Careful: do not run this method unless the table-mutex is locked!
+	// It will unlock it for the caller before running the callbacks and checks
+	table.log("Adding item with key", item.key, "and lifespan of", item.lifeSpan, "to table", table.name)
+	table.items[item.key] = item
+
+	// Cache values so we don't keep blocking the mutex.
+	expDur := table.cleanupInterval
+	addedItem := table.addedItem
+	table.Unlock()
+
+	// Trigger callback after adding an item to cache.
+	if addedItem != nil {
+		for _, callback := range addedItem {
+			callback(item)
+		}
+	}
+
+	// If we haven't set up any expiration check timer or found a more imminent item.
+	if item.lifeSpan > 0 && (expDur == 0 || item.lifeSpan < expDur) {
+		table.expirationCheck()
+	}
+}
+
+// Add adds a key/value pair to the cache.
+// Parameter key is the item's cache-key.
+// Parameter lifeSpan determines after which time period without an access the item
+// will get removed from the cache.
+// Parameter data is the item's value.
+func (table *CacheTable) Add(key interface{}, lifeSpan time.Duration, data interface{}) *CacheItem {
+	item := NewCacheItem(key, lifeSpan, data)
+
+	// Add item to cache.
+	table.Lock()
+	table.addInternal(item)
+
+	return item
+}
+
+func (table *CacheTable) deleteInternal(key interface{}) (*CacheItem, error) {
+	r, ok := table.items[key]
+	if !ok {
+		return nil, ErrKeyNotFound
+	}
+
+	// Cache value so we don't keep blocking the mutex.
+	aboutToDeleteItem := table.aboutToDeleteItem
+	table.Unlock()
+
+	// Trigger callbacks before deleting an item from cache.
+	if aboutToDeleteItem != nil {
+		for _, callback := range aboutToDeleteItem {
+			callback(r)
+		}
+	}
+
+	r.RLock()
+	defer r.RUnlock()
+	if r.aboutToExpire != nil {
+		for _, callback := range r.aboutToExpire {
+			callback(key)
+		}
+	}
+
+	table.Lock()
+	table.log("Deleting item with key", key, "created on", r.createdOn, "and hit", r.accessCount, "times from table", table.name)
+	delete(table.items, key)
+
+	return r, nil
+}
+
+// Delete an item from the cache.
+func (table *CacheTable) Delete(key interface{}) (*CacheItem, error) {
+	table.Lock()
+	defer table.Unlock()
+
+	return table.deleteInternal(key)
+}
+
+// Exists returns whether an item exists in the cache. Unlike the Value method
+// Exists neither tries to fetch data via the loadData callback nor does it
+// keep the item alive in the cache.
+func (table *CacheTable) Exists(key interface{}) bool {
+	table.RLock()
+	defer table.RUnlock()
+	_, ok := table.items[key]
+
+	return ok
+}
+
+// NotFoundAdd checks whether an item is not yet cached. Unlike the Exists
+// method this also adds data if the key could not be found.
+func (table *CacheTable) NotFoundAdd(key interface{}, lifeSpan time.Duration, data interface{}) bool {
+	table.Lock()
+
+	if _, ok := table.items[key]; ok {
+		table.Unlock()
+		return false
+	}
+
+	item := NewCacheItem(key, lifeSpan, data)
+	table.addInternal(item)
+
+	return true
+}
+
+// Value returns an item from the cache and marks it to be kept alive. You can
+// pass additional arguments to your DataLoader callback function.
+func (table *CacheTable) Value(key interface{}, args ...interface{}) (*CacheItem, error) {
+	table.RLock()
+	r, ok := table.items[key]
+	loadData := table.loadData
+	table.RUnlock()
+
+	if ok {
+		// Update access counter and timestamp.
+		r.KeepAlive()
+		return r, nil
+	}
+
+	// Item doesn't exist in cache. Try and fetch it with a data-loader.
+	if loadData != nil {
+		item := loadData(key, args...)
+		if item != nil {
+			table.Add(key, item.lifeSpan, item.data)
+			return item, nil
+		}
+
+		return nil, ErrKeyNotFoundOrLoadable
+	}
+
+	return nil, ErrKeyNotFound
+}
+
+// Peek returns an item from the cache, but does not mark its active status, i.e. does not update the active time.
+// You can also pass additional arguments to your DataLoader callback function.
+func (table *CacheTable) Peek(key interface{}, args ...interface{}) (*CacheItem, error) {
+	table.RLock()
+	r, ok := table.items[key]
+	loadData := table.loadData
+	table.RUnlock()
+
+	if ok {
+		r.AddAccessCount()
+		return r, nil
+	}
+
+	// Item doesn't exist in cache. Try and fetch it with a data-loader.
+	if loadData != nil {
+		item := loadData(key, args...)
+		if item != nil {
+			table.Add(key, item.lifeSpan, item.data)
+			return item, nil
+		}
+
+		return nil, ErrKeyNotFoundOrLoadable
+	}
+
+	return nil, ErrKeyNotFound
+}
+
+// Flush deletes all items from this cache table.
+func (table *CacheTable) Flush() {
+	table.Lock()
+	defer table.Unlock()
+
+	table.log("Flushing table", table.name)
+
+	table.items = make(map[interface{}]*CacheItem)
+	table.cleanupInterval = 0
+	if table.cleanupTimer != nil {
+		table.cleanupTimer.Stop()
+	}
+}
+
+// CacheItemPair maps key to access counter
+type CacheItemPair struct {
+	Key         interface{}
+	AccessCount int64
+}
+
+// CacheItemPairList is a slice of CacheItemPairs that implements sort.
+// Interface to sort by AccessCount.
+type CacheItemPairList []CacheItemPair
+
+func (p CacheItemPairList) Swap(i, j int)      { p[i], p[j] = p[j], p[i] }
+func (p CacheItemPairList) Len() int           { return len(p) }
+func (p CacheItemPairList) Less(i, j int) bool { return p[i].AccessCount > p[j].AccessCount }
+
+// MostAccessed returns the most accessed items in this cache table
+func (table *CacheTable) MostAccessed(count int64) []*CacheItem {
+	table.RLock()
+	defer table.RUnlock()
+
+	p := make(CacheItemPairList, len(table.items))
+	i := 0
+	for k, v := range table.items {
+		p[i] = CacheItemPair{k, v.accessCount}
+		i++
+	}
+	sort.Sort(p)
+
+	var r []*CacheItem
+	c := int64(0)
+	for _, v := range p {
+		if c >= count {
+			break
+		}
+
+		item, ok := table.items[v.Key]
+		if ok {
+			r = append(r, item)
+		}
+		c++
+	}
+
+	return r
+}
+
+// Internal logging method for convenience.
+func (table *CacheTable) log(v ...interface{}) {
+	if table.logger == nil {
+		return
+	}
+
+	table.logger.Println(v...)
+}

mycache/cache2go/errors.go

@@ -0,0 +1,20 @@
+/*
+ * Simple caching library with expiration capabilities
+ *     Copyright (c) 2013-2017, Christian Muehlhaeuser <muesli@gmail.com>
+ *
+ *   For license see LICENSE.txt
+ */
+
+package cache2go
+
+import (
+	"errors"
+)
+
+var (
+	// ErrKeyNotFound gets returned when a specific key couldn't be found
+	ErrKeyNotFound = errors.New("Key not found in cache")
+	// ErrKeyNotFoundOrLoadable gets returned when a specific key couldn't be
+	// found and loading via the data-loader callback also failed
+	ErrKeyNotFoundOrLoadable = errors.New("Key not found and could not be loaded into cache")
+)

mycache/cache2go/examples/callbacks/callbacks.go

@@ -0,0 +1,51 @@
+package main
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/xxjwxc/public/mycache/cache2go"
+)
+
+func main() {
+	cache := cache2go.Cache("myCache")
+
+	// This callback will be triggered every time a new item
+	// gets added to the cache.
+	cache.SetAddedItemCallback(func(entry *cache2go.CacheItem) {
+		fmt.Println("Added Callback 1:", entry.Key(), entry.Data(), entry.CreatedOn())
+	})
+	cache.AddAddedItemCallback(func(entry *cache2go.CacheItem) {
+		fmt.Println("Added Callback 2:", entry.Key(), entry.Data(), entry.CreatedOn())
+	})
+	// This callback will be triggered every time an item
+	// is about to be removed from the cache.
+	cache.SetAboutToDeleteItemCallback(func(entry *cache2go.CacheItem) {
+		fmt.Println("Deleting:", entry.Key(), entry.Data(), entry.CreatedOn())
+	})
+
+	// Caching a new item will execute the AddedItem callback.
+	cache.Add("someKey", 0, "This is a test!")
+
+	// Let's retrieve the item from the cache
+	res, err := cache.Value("someKey")
+	if err == nil {
+		fmt.Println("Found value in cache:", res.Data())
+	} else {
+		fmt.Println("Error retrieving value from cache:", err)
+	}
+
+	// Deleting the item will execute the AboutToDeleteItem callback.
+	cache.Delete("someKey")
+
+	cache.RemoveAddedItemCallbacks()
+	// Caching a new item that expires in 3 seconds
+	res = cache.Add("anotherKey", 3*time.Second, "This is another test")
+
+	// This callback will be triggered when the item is about to expire
+	res.SetAboutToExpireCallback(func(key interface{}) {
+		fmt.Println("About to expire:", key.(string))
+	})
+
+	time.Sleep(5 * time.Second)
+}

mycache/cache2go/examples/dataloader/dataloader.go

@@ -0,0 +1,34 @@
+package main
+
+import (
+	"fmt"
+	"strconv"
+
+	"github.com/xxjwxc/public/mycache/cache2go"
+)
+
+func main() {
+	cache := cache2go.Cache("myCache")
+
+	// The data loader gets called automatically whenever something
+	// tries to retrieve a non-existing key from the cache.
+	cache.SetDataLoader(func(key interface{}, args ...interface{}) *cache2go.CacheItem {
+		// Apply some clever loading logic here, e.g. read values for
+		// this key from database, network or file.
+		val := "This is a test with key " + key.(string)
+
+		// This helper method creates the cached item for us. Yay!
+		item := cache2go.NewCacheItem(key, 0, val)
+		return item
+	})
+
+	// Let's retrieve a few auto-generated items from the cache.
+	for i := 0; i < 10; i++ {
+		res, err := cache.Value("someKey_" + strconv.Itoa(i))
+		if err == nil {
+			fmt.Println("Found value in cache:", res.Data())
+		} else {
+			fmt.Println("Error retrieving value from cache:", err)
+		}
+	}
+}

mycache/cache2go/examples/mycachedapp/mycachedapp.go

@@ -0,0 +1,53 @@
+package main
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/xxjwxc/public/mycache/cache2go"
+)
+
+// Keys & values in cache2go can be of arbitrary types, e.g. a struct.
+type myStruct struct {
+	text     string
+	moreData []byte
+}
+
+func main() {
+	// Accessing a new cache table for the first time will create it.
+	cache := cache2go.Cache("myCache")
+
+	// We will put a new item in the cache. It will expire after
+	// not being accessed via Value(key) for more than 5 seconds.
+	val := myStruct{"This is a test!", []byte{}}
+	cache.Add("someKey", 5*time.Second, &val)
+
+	// Let's retrieve the item from the cache.
+	res, err := cache.Value("someKey")
+	if err == nil {
+		fmt.Println("Found value in cache:", res.Data().(*myStruct).text)
+	} else {
+		fmt.Println("Error retrieving value from cache:", err)
+	}
+
+	// Wait for the item to expire in cache.
+	time.Sleep(6 * time.Second)
+	res, err = cache.Value("someKey")
+	if err != nil {
+		fmt.Println("Item is not cached (anymore).")
+	}
+
+	// Add another item that never expires.
+	cache.Add("someKey", 0, &val)
+
+	// cache2go supports a few handy callbacks and loading mechanisms.
+	cache.SetAboutToDeleteItemCallback(func(e *cache2go.CacheItem) {
+		fmt.Println("Deleting:", e.Key(), e.Data().(*myStruct).text, e.CreatedOn())
+	})
+
+	// Remove the item from the cache.
+	cache.Delete("someKey")
+
+	// And wipe the entire cache table.
+	cache.Flush()
+}

mycache/mycache.go

@@ -1,12 +1,12 @@
 /*
- key/value 内存缓存，支持基于超时的自动无效功能
+key/value 内存缓存，支持基于超时的自动无效功能
 */
 package mycache
 
 import (
 	"time"
 
-	"github.com/muesli/cache2go"
+	"github.com/xxjwxc/public/mycache/cache2go"
 	"github.com/xxjwxc/public/serializing"
 )
 
@@ -21,7 +21,6 @@ type CacheIFS interface {
 	Close() (err error)                                                   // 关闭连接
 }
 
-
 // MyCache 内存缓存
 type MyCache struct {
 	cache *cache2go.CacheTable
@@ -47,7 +46,7 @@ func (mc *MyCache) Add(key interface{}, value interface{}, lifeSpan time.Duratio
 
 // Value 查找一个cache
 func (mc *MyCache) Value(key interface{}, value interface{}) error {
-	res, err := mc.cache.Value(key)
+	res, err := mc.cache.Peek(key)
 	if err == nil {
 		bt := res.Data().([]byte)
 		return decodeValue(bt, value)

mycache1/mycache.go

@@ -1,12 +1,12 @@
 /*
- key/value 内存缓存，支持基于超时的自动无效功能
+key/value 内存缓存，支持基于超时的自动无效功能
 */
 package mycache
 
 import (
 	"time"
 
-	"github.com/muesli/cache2go"
+	"github.com/xxjwxc/public/mycache/cache2go"
 )
 
 // MyCache 内存缓存
@@ -15,8 +15,8 @@ type MyCache struct {
 }
 
 /*
-	初始化一个cache
-	cachename 缓存名字
+初始化一个cache
+cachename 缓存名字
 */
 func NewCache(cachename string) (mc *MyCache) {
 	mc = &MyCache{}
@@ -25,8 +25,8 @@ func NewCache(cachename string) (mc *MyCache) {
 }
 
 /*
-	添加一个缓存
-	lifeSpan:缓存时间，0表示永不超时
+添加一个缓存
+lifeSpan:缓存时间，0表示永不超时
 */
 func (mc *MyCache) Add(key interface{}, value interface{}, lifeSpan time.Duration) *cache2go.CacheItem {
 	return mc.cache.Add(key, lifeSpan, value)
@@ -49,14 +49,14 @@ func (mc *MyCache) Value(key interface{}) (value interface{}, b bool) {
 }
 
 /*
-	判断key是否存在
+判断key是否存在
 */
 func (mc *MyCache) IsExist(key interface{}) bool {
 	return mc.cache.Exists(key)
 }
 
 /*
- 删除一个cache
+删除一个cache
 */
 func (mc *MyCache) Delete(key interface{}) error {
 	_, err := mc.cache.Delete(key)
@@ -64,14 +64,14 @@ func (mc *MyCache) Delete(key interface{}) error {
 }
 
 /*
-	获取原始cache2go操作类
+获取原始cache2go操作类
 */
 func (mc *MyCache) GetCache2go() *cache2go.CacheTable {
 	return mc.cache
 }
 
 /*
-	清空表內容
+清空表內容
 */
 func (mc *MyCache) Clear() bool {
 	mc.cache.Flush()