-
Notifications
You must be signed in to change notification settings - Fork 0
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Merge pull request #56 from untangle/MFW-2125-Cache-GEOIP-data
MFW 2125: Cache GeoIP Data: Added a generic Random Replacement Cache and Least Recently Used cache. Also added a sweeper for these caches that starts a sweep of the cache on a timer.
- Loading branch information
Showing
9 changed files
with
777 additions
and
63 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,12 @@ | ||
| package cacher | ||
|
|
||
| // Interface for structs implementing a basic caching functionality | ||
| type Cacher interface { | ||
| Get(string) (interface{}, bool) | ||
| Put(string, interface{}) | ||
| Clear() | ||
| Remove(string) | ||
|
|
||
| // Runs a given function on each cache element | ||
| ForEach(func(string, interface{}) bool) | ||
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,162 @@ | ||
| package cacher | ||
|
|
||
| import ( | ||
| "container/list" | ||
| "sync" | ||
|
|
||
| "github.com/untangle/golang-shared/services/logger" | ||
| ) | ||
|
|
||
| // Attach the key, used to look up a value in the cache, to its value. | ||
| type KeyPair struct { | ||
| Key string | ||
| Value interface{} | ||
| } | ||
|
|
||
| // A simple LRU Cache implementation. The least recently used element | ||
| // in the cache are removed if the cache's max capacity is hit. The cache's | ||
| // mutex cannot be a RWMutex since Gets alter the cache's underlying data structures. | ||
| // Slower concurrent performance than a Random Removal cache, but more cache hits. | ||
| // O(1) reads and O(1) insertions. | ||
| type LruCache struct { | ||
| capacity uint | ||
| list *list.List | ||
| cacheMutex sync.Mutex | ||
| elements map[string]*list.Element | ||
|
|
||
| // Name of your cache. Only used to provide accurate logging | ||
| cacheName string | ||
| } | ||
|
|
||
| // Returns a pointer to a newly initialized LruCache with it's capacity and name set to | ||
| // those provided by capactiy and cacheName, respectively | ||
| func NewLruCache(capacity uint, cacheName string) *LruCache { | ||
| return &LruCache{ | ||
| capacity: capacity, | ||
| list: list.New(), | ||
| elements: make(map[string]*list.Element), | ||
| cacheName: cacheName, | ||
| } | ||
| } | ||
|
|
||
| // Iterates over each key, value pair in the cache and runs them through | ||
| // the provided cleanup function. If the cleanup function provided returns true, | ||
| // The element will be removed from the cache. The cleanupFunction provided | ||
| // will be given the key and the value of the current element. | ||
| func (cache *LruCache) ForEach(cleanupFunc func(string, interface{}) bool) { | ||
| cache.cacheMutex.Lock() | ||
| defer cache.cacheMutex.Unlock() | ||
|
|
||
| for key, val := range cache.elements { | ||
| // Remove element if the cleanUp func returns true | ||
| if cleanupFunc(key, val.Value.(*list.Element).Value.(KeyPair).Value) { | ||
| cache.removeElementNoLock(key) | ||
| } | ||
| } | ||
|
|
||
| } | ||
|
|
||
| // Gets an item from the cache using a provided key. Once an item has been | ||
| // retrieved, move it to the front of the cache's queue. Return a bool to | ||
| // signify a value was found since a key could be mapped to nil. | ||
| func (cache *LruCache) Get(key string) (interface{}, bool) { | ||
| var value interface{} | ||
| var found bool | ||
|
|
||
| cache.cacheMutex.Lock() | ||
| defer cache.cacheMutex.Unlock() | ||
| if node, ok := cache.elements[key]; ok { | ||
| value = node.Value.(*list.Element).Value.(KeyPair).Value | ||
| found = true | ||
| cache.list.MoveToFront(node) | ||
| } | ||
|
|
||
| return value, found | ||
| } | ||
|
|
||
| // Add an item to the cache and move it to the front of the queue. | ||
| // If the item's key is already in the cache, update the key's value | ||
| // and move the the item to the front of the queue. | ||
| func (cache *LruCache) Put(key string, value interface{}) { | ||
| cache.cacheMutex.Lock() | ||
| defer cache.cacheMutex.Unlock() | ||
|
|
||
| // Update key's value if already present in the cache | ||
| if node, ok := cache.elements[key]; ok { | ||
| cache.list.MoveToFront(node) | ||
| node.Value.(*list.Element).Value = KeyPair{Key: key, Value: value} | ||
|
|
||
| logger.Debug("Updated the element with key %s in the cache named %s", key, cache.cacheName) | ||
| } else { | ||
| // Remove least recently used item in cache if the cache's capacity has reached its limit | ||
| if uint(cache.list.Len()) >= cache.capacity { | ||
| // Remove node from the cache's internal map | ||
| elementToRemove := cache.list.Back().Value.(*list.Element).Value.(KeyPair).Key | ||
| delete(cache.elements, elementToRemove) | ||
|
|
||
| cache.list.Remove(cache.list.Back()) | ||
| logger.Debug("Removed element with key %s from the cache named %s", key, cache.cacheName) | ||
| } | ||
|
|
||
| newNode := &list.Element{ | ||
| Value: KeyPair{ | ||
| Key: key, | ||
| Value: value, | ||
| }, | ||
| } | ||
|
|
||
| mostRecentlyUsed := cache.list.PushFront(newNode) | ||
| cache.elements[key] = mostRecentlyUsed | ||
| logger.Debug("Added element with key %s to the cache named %s", key, cache.cacheName) | ||
| } | ||
| } | ||
|
|
||
| // Removes an element from the cache. | ||
| // Does NOT take the cache's lock. Functions calling removeElementNoLock() | ||
| // need to do it themselves | ||
| func (cache *LruCache) removeElementNoLock(key string) { | ||
| if node, ok := cache.elements[key]; ok { | ||
| delete(cache.elements, key) | ||
| cache.list.Remove(node) | ||
| logger.Debug("Removed element with key %s from the cache name %s", key, cache.cacheName) | ||
| } | ||
| } | ||
|
|
||
| // Delete an item from the cache based off the key | ||
| func (cache *LruCache) Remove(key string) { | ||
| cache.cacheMutex.Lock() | ||
| defer cache.cacheMutex.Unlock() | ||
| cache.removeElementNoLock(key) | ||
| } | ||
|
|
||
| // Clear all all internal data structures | ||
| func (cache *LruCache) Clear() { | ||
| cache.cacheMutex.Lock() | ||
| defer cache.cacheMutex.Unlock() | ||
| cache.elements = make(map[string]*list.Element) | ||
| cache.list.Init() | ||
| logger.Debug("Cleared cache of name %s", cache.cacheName) | ||
| } | ||
|
|
||
| // Gets the most recently looked up value in the cache | ||
| func (cache *LruCache) GetMostRecentlyUsed() (string, interface{}) { | ||
| cache.cacheMutex.Lock() | ||
| defer cache.cacheMutex.Unlock() | ||
| keyPair := cache.list.Front().Value.(*list.Element).Value.(KeyPair) | ||
| return keyPair.Key, keyPair.Value | ||
| } | ||
|
|
||
| // Get the least recently looked up value on the cache | ||
| func (cache *LruCache) GetLeastRecentlyUsed() (string, interface{}) { | ||
| cache.cacheMutex.Lock() | ||
| defer cache.cacheMutex.Unlock() | ||
| keyPair := cache.list.Back().Value.(*list.Element).Value.(KeyPair) | ||
| return keyPair.Key, keyPair.Value | ||
| } | ||
|
|
||
| // Gets the total number of elements currently in the cache | ||
| func (cache *LruCache) GetTotalElements() int { | ||
| cache.cacheMutex.Lock() | ||
| defer cache.cacheMutex.Unlock() | ||
| return cache.list.Len() | ||
| } |
Oops, something went wrong.