Completed basic query cache

cache_store.go

@@ -3,6 +3,8 @@ package gorm
 import (
 	"fmt"
 	"os"
+	"reflect"
+	"sort"
 	"strconv"
 	"sync"
 	"time"
@@ -20,7 +22,10 @@ type cache struct {
 	size          int
 	highWaterMark int
 	enabled       bool
+	idMapMutex    sync.RWMutex
+	idMapping     map[modelId][]string
 	database      map[string]*cacheItem
+	mutex         sync.RWMutex
 }
 
 func (c *cache) Enable() {
@@ -38,43 +43,167 @@ func (c *cache) Enable() {
 	c.size, _ = strconv.Atoi(size)
 	c.highWaterMark, _ = strconv.Atoi(highWaterMark)
 
-	c.database = make(map[string]*cacheItem, c.size)
+	fmt.Println("Cache High Water Mark: ", c.highWaterMark)
+	fmt.Println("Cache Size: ", c.size)
+
+	c.database = make(map[string]*cacheItem, c.size*2) // Size is larger to allow for temporary bursting
+	c.idMapping = make(map[modelId][]string, 100)
+
+	ticker := time.NewTicker(5 * time.Second)
+
+	go func() {
+		for {
+			select {
+			case <-ticker.C:
+				c.Empty()
+			}
+		}
+	}()
 
 	c.enabled = true
 }
 
+type KeyValue struct {
+	Key   string
+	Value *cacheItem
+}
+
+func (c cache) Empty() {
+	if len(c.database) > c.size {
+		fmt.Println("Over the limit. Running cleanup")
+
+		var s []KeyValue
+		c.mutex.RLock()
+		for k, v := range c.database {
+			s = append(s, KeyValue{
+				Key:   k,
+				Value: v,
+			})
+		}
+		c.mutex.RUnlock()
+
+		// Sort the results
+		sort.Slice(s, func(i, j int) bool {
+			return s[i].Value.accessCount < s[j].Value.accessCount
+		})
+
+		// Go through the end of the results list and knock those keys off
+		c.mutex.Lock()
+		for _, res := range s[c.highWaterMark : len(s)-1] {
+			fmt.Println("Cleaned up query " + res.Key + " having only " + strconv.Itoa(int(res.Value.accessCount)) + " accesses.")
+			delete(c.database, res.Key)
+		}
+		c.mutex.Unlock()
+	}
+}
+
 func (c cache) GetItem(key string, offset int64) interface{} {
-	fmt.Println("Getting item " + key)
+	fmt.Print("Getting item " + key + " ... ")
 
+	c.mutex.RLock()
 	if item, ok := c.database[key]; ok {
-		item.dataMutex.RLock()
 		item.accessMutex.Lock()
-
-		defer item.dataMutex.RUnlock()
-		defer item.accessMutex.Unlock()
-
 		item.accessCount++
+		item.accessMutex.Unlock()
 
-		if (item.created+offset < time.Now().Unix()) || offset == -1 {
+		item.dataMutex.RLock()
+		defer item.dataMutex.RUnlock()
+
+		if (item.created+offset > time.Now().Unix()) || offset == -1 {
+			fmt.Print("Found \n")
+			c.mutex.RUnlock()
 			return item.data
 		}
+
+		fmt.Print("Expired \n")
+	} else {
+		fmt.Print("Not found \n")
 	}
 
+	c.mutex.RUnlock()
 	return nil
 }
 
+type modelId struct {
+	model string
+	id    string
+}
+
 func (c *cache) StoreItem(key string, data interface{}) {
 	fmt.Println("Storing item " + key)
 
-	if _, ok := c.database[key]; !ok {
-		c.database[key] = &cacheItem{
-			data:    data,
-			created: time.Now().Unix(),
+	// Affected IDs
+	affectedIDs := make([]string, 0, 100)
+	var model string
+
+	// Go through the IDs in the interface and add them and the model to the
+	switch reflect.TypeOf(data).Kind() {
+	case reflect.Slice:
+		// Loop through each of the items and get the primary key or "ID" value
+		s := reflect.ValueOf(data)
+		model = reflect.TypeOf(data).Elem().String()
+
+		for i := 0; i < s.Len(); i++ {
+			affectedIDs = append(affectedIDs, getID(s.Index(i).Interface()))
 		}
+
+	case reflect.Struct:
+		model = reflect.TypeOf(data).String()
+		affectedIDs = []string{getID(data)}
+	}
+
+	if _, ok := c.database[key]; !ok {
+		c.mutex.Lock()
+		c.database[key] = &cacheItem{
+			created:     time.Now().UnixNano(),
+			accessCount: 1,
+			data:        data,
+		}
+		c.mutex.Unlock()
 	} else {
+		c.mutex.RLock()
 		c.database[key].dataMutex.Lock()
 		c.database[key].data = data
-		c.database[key].created = time.Now().Unix()
+		c.database[key].created = time.Now().UnixNano()
 		c.database[key].dataMutex.Unlock()
+		c.mutex.RUnlock()
 	}
+
+	// Store the query selector agains the relevent IDs
+	c.idMapMutex.Lock()
+	for _, id := range affectedIDs {
+		sel := modelId{model: model, id: id}
+
+		if _, ok := c.idMapping[sel]; !ok {
+			// We need to create the array
+			c.idMapping[sel] = []string{key}
+		} else {
+			c.idMapping[sel] = append(c.idMapping[sel], key)
+		}
+	}
+	c.idMapMutex.Unlock()
+}
+
+func (c *cache) Expireitem(model, id string) {
+	// Get the relevent cache items
+	sel := modelId{model: model, id: id}
+	c.idMapMutex.Lock()
+	items := c.idMapping[sel]
+	delete(c.idMapping, sel)
+	c.idMapMutex.Unlock()
+
+	// Delete the items from the cache
+	c.mutex.Lock()
+	for _, key := range items {
+		fmt.Println("Expiring item " + key + "(based on " + model + "/" + id)
+		delete(c.database, key)
+	}
+	c.mutex.Unlock()
+}
+
+func getID(data interface{}) string {
+	d := reflect.ValueOf(data)
+	idField := d.FieldByName("ID")
+
+	return fmt.Sprint(idField.Interface())
 }

callback_query.go

@@ -78,15 +78,19 @@ func queryCallback(scope *Scope) {
 				cacheResults := scope.CacheStore().GetItem(key, *cacheOperation)
 				if cacheResults != nil {
 					results.Set(reflect.ValueOf(cacheResults))
+					fmt.Println("Cache HIT")
 					readFromDB = false
 				} else {
 					readFromDB = true
+					fmt.Println()
 					writeToCache = true
 				}
 			} else {
 				readFromDB = true
 				writeToCache = true
 			}
+		} else {
+			fmt.Println("Cache NOT")
 		}
 
 		if readFromDB {

go.mod

@@ -5,7 +5,6 @@ go 1.12
 require (
 	github.com/denisenkom/go-mssqldb v0.0.0-20190515213511-eb9f6a1743f3
 	github.com/erikstmartin/go-testdb v0.0.0-20160219214506-8d10e4a1bae5
-	github.com/go-redis/redis v6.15.2+incompatible
 	github.com/go-sql-driver/mysql v1.4.1
 	github.com/jinzhu/inflection v1.0.0
 	github.com/jinzhu/now v1.0.1

main.go

@@ -24,6 +24,7 @@ type DB struct {
 	logMode           logModeValue
 	logger            logger
 	search            *search
+	cache             *cache
 	values            sync.Map
 
 	// global db
@@ -161,6 +162,21 @@ func (s *DB) LogMode(enable bool) *DB {
 	return s
 }
 
+// EnableCache turns on query caching
+func (s *DB) EnableCache() *DB {
+	fmt.Println("Enabling caching...")
+	s.cache = new(cache)
+	s.cache.Enable()
+
+	return s
+}
+
+// FlushCacheItem takes a model with its ID field set and searches the caches for it. If found, that cache item is deleted
+func (s *DB) FlushCacheItem(model, id string) *DB {
+	s.cache.Expireitem(model, id)
+	return s
+}
+
 // SetNowFuncOverride set the function to be used when creating a new timestamp
 func (s *DB) SetNowFuncOverride(nowFuncOverride func() time.Time) *DB {
 	s.nowFuncOverride = nowFuncOverride

model_struct.go

@@ -52,6 +52,18 @@ func (s *ModelStruct) TableName(db *DB) string {
 	return DefaultTableNameHandler(db, s.defaultTableName)
 }
 
+// TableName returns model's table name
+func (s *ModelStruct) Cache(db *DB) *int64 {
+	if db != nil && s.ModelType != nil {
+		// Set default table name
+		if cache, ok := reflect.New(s.ModelType).Interface().(cacher); ok {
+			return cache.Cache()
+		}
+	}
+
+	return nil
+}
+
 // StructField model field's struct definition
 type StructField struct {
 	DBName          string

scope.go

@@ -24,7 +24,6 @@ type Scope struct {
 	skipLeft        bool
 	fields          *[]*Field
 	selectAttrs     *[]string
-	cacheStore      *cache
 }
 
 // IndirectValue return scope's reflect value's indirect value
@@ -48,7 +47,7 @@ func (scope *Scope) DB() *DB {
 
 // CacheStore returns scope's cache store
 func (scope *Scope) CacheStore() *cache {
-	return scope.cacheStore
+	return scope.db.parent.cache
 }
 
 // NewDB create a new DB without search information
@@ -338,10 +337,12 @@ type dbTabler interface {
 }
 
 func (scope *Scope) Cache() *int64 {
-	if scope.cacheStore.enabled {
-		if cacher, ok := scope.Value.(cacher); ok {
-			return cacher.Cache()
+	if scope.CacheStore() != nil && scope.CacheStore().enabled {
+		if cache, ok := scope.Value.(cacher); ok {
+			return cache.Cache()
 		}
+
+		return scope.GetModelStruct().Cache(scope.db.Model(scope.Value))
 	}
 
 	return nil