Gocache
Guess what is Gocache? a Go cache library. This is an extendable cache library that brings you a lot of features for caching data.
Overview
Here is what it brings in detail:
-
✅ Multiple cache stores: actually in memory, redis, or your own custom store -
✅ A chain cache: use multiple cache with a priority order (memory then fallback to a redis shared cache for instance) -
✅ A loadable cache: allow you to call a callback function to put your data back in cache -
✅ A metric cache to let you store metrics about your caches usage (hits, miss, set success, set error, ...) -
✅ A marshaler to automatically marshal/unmarshal your cache values as a struct -
✅ Define default values in stores and override them when setting data -
✅ Cache invalidation by expiration time and/or using tags
Built-in stores
- Memory (bigcache) (allegro/bigcache)
- Memory (ristretto) (dgraph-io/ristretto)
- Memcache (bradfitz/memcache)
- Redis (go-redis/redis)
- Freecache (coocood/freecache)
- More to come soon
Built-in metrics providers
Available cache features in detail
A simple cache
Here is a simple cache instanciation with Redis but you can also look at other available stores:
Memcache
memcacheStore := store.NewMemcache(
memcache.New("10.0.0.1:11211", "10.0.0.2:11211", "10.0.0.3:11212"),
&store.Options{
Expiration: 10*time.Second,
},
)
cacheManager := cache.New(memcacheStore)
err := cacheManager.Set("my-key", []byte("my-value"), &store.Options{
Expiration: 15*time.Second, // Override default value of 10 seconds defined in the store
})
if err != nil {
panic(err)
}
value := cacheManager.Get("my-key")
cacheManager.Delete("my-key")
cacheManager.Clear() // Clears the entire cache, in case you want to flush all cache
Memory (using Bigcache)
bigcacheClient, _ := bigcache.NewBigCache(bigcache.DefaultConfig(5 * time.Minute))
bigcacheStore := store.NewBigcache(bigcacheClient, nil) // No otions provided (as second argument)
cacheManager := cache.New(bigcacheStore)
err := cacheManager.Set("my-key", []byte("my-value"), nil)
if err != nil {
panic(err)
}
value := cacheManager.Get("my-key")
Memory (using Ristretto)
ristrettoCache, err := ristretto.NewCache(&ristretto.Config{
NumCounters: 1000,
MaxCost: 100,
BufferItems: 64,
})
if err != nil {
panic(err)
}
ristrettoStore := store.NewRistretto(ristrettoCache, nil)
cacheManager := cache.New(ristrettoStore)
err := cacheManager.Set("my-key", "my-value", &store.Options{Cost: 2})
if err != nil {
panic(err)
}
value := cacheManager.Get("my-key")
cacheManager.Delete("my-key")
Redis
redisStore := store.NewRedis(redis.NewClient(&redis.Options{
Addr: "127.0.0.1:6379",
}), nil)
cacheManager := cache.New(redisStore)
err := cacheManager.Set("my-key", "my-value", &store.Options{Expiration: 15*time.Second})
if err != nil {
panic(err)
}
value, err := cacheManager.Get("my-key")
switch err {
case nil:
fmt.Printf("Get the key '%s' from the redis cache. Result: %s", "my-key", value)
case redis.Nil:
fmt.Printf("Failed to find the key '%s' from the redis cache.", "my-key")
default:
fmt.Printf("Failed to get the value from the redis cache with key '%s': %v", "my-key", err)
}
Freecache
freecacheStore := store.NewFreecache(freecache.NewCache(1000), &Options{
Expiration: 10 * time.Second,
})
cacheManager := cache.New(freecacheStore)
err := cacheManager.Set("by-key", []byte("my-value"), opts)
if err != nil {
panic(err)
}
value := cacheManager.Get("my-key")
A chained cache
Here, we will chain caches in the following order: first in memory with Ristretto store, then in Redis (as a fallback):
// Initialize Ristretto cache and Redis client
ristrettoCache, err := ristretto.NewCache(&ristretto.Config{NumCounters: 1000, MaxCost: 100, BufferItems: 64})
if err != nil {
panic(err)
}
redisClient := redis.NewClient(&redis.Options{Addr: "127.0.0.1:6379"})
// Initialize stores
ristrettoStore := store.NewRistretto(ristrettoCache, nil)
redisStore := store.NewRedis(redisClient, &store.Options{Expiration: 5*time.Second})
// Initialize chained cache
cacheManager := cache.NewChain(
cache.New(ristrettoStore),
cache.New(redisStore),
)
// ... Then, do what you want with your cache
Chain cache also put data back in previous caches when it's found so in this case, if ristretto doesn't have the data in its cache but redis have, data will also get setted back into ristretto (memory) cache.
A loadable cache
This cache will provide a load function that acts as a callable function and will set your data back in your cache in case they are not available:
// Initialize Redis client and store
redisClient := redis.NewClient(&redis.Options{Addr: "127.0.0.1:6379"})
redisStore := store.NewRedis(redisClient, nil)
// Initialize a load function that loads your data from a custom source
loadFunction := func(key interface{}) (interface{}, error) {
// ... retrieve value from available source
return &Book{ID: 1, Name: "My test amazing book", Slug: "my-test-amazing-book"}, nil
}
// Initialize loadable cache
cacheManager := cache.NewLoadable(
loadFunction,
cache.New(redisStore),
)
// ... Then, you can get your data and your function will automatically put them in cache(s)
Of course, you can also pass a Chain cache into the Loadable one so if your data is not available in all caches, it will bring it back in all caches.
A metric cache to retrieve cache statistics
This cache will record metrics depending on the metric provider you pass to it. Here we give a Prometheus provider:
// Initialize Redis client and store
redisClient := redis.NewClient(&redis.Options{Addr: "127.0.0.1:6379"})
redisStore := store.NewRedis(redisClient, nil)
// Initializes Prometheus metrics service
promMetrics := metrics.NewPrometheus("my-test-app")
// Initialize metric cache
cacheManager := cache.NewMetric(
promMetrics,
cache.New(redisStore),
)
// ... Then, you can get your data and metrics will be observed by Prometheus
A marshaler wrapper
Some caches like Redis stores and returns the value as a string so you have to marshal/unmarshal your structs if you want to cache an object. That's why we bring a marshaler service that wraps your cache and make the work for you:
// Initialize Redis client and store
redisClient := redis.NewClient(&redis.Options{Addr: "127.0.0.1:6379"})
redisStore := store.NewRedis(redisClient, nil)
// Initialize chained cache
cacheManager := cache.NewMetric(
promMetrics,
cache.New(redisStore),
)
// Initializes marshaler
marshal := marshaler.New(cacheManager)
key := BookQuery{Slug: "my-test-amazing-book"}
value := Book{ID: 1, Name: "My test amazing book", Slug: "my-test-amazing-book"}
err = marshal.Set(key, value)
if err != nil {
panic(err)
}
returnedValue, err := marshal.Get(key, new(Book))
if err != nil {
panic(err)
}
// Then, do what you want with the value
marshal.Delete("my-key")
The only thing you have to do is to specify the struct in which you want your value to be un-marshalled as a second argument when calling the .Get() method.
Cache invalidation using tags
You can attach some tags to items you create so you can easily invalidate some of them later.
Tags are stored using the same storage you choose for your cache.
Here is an example on how to use it:
// Initialize Redis client and store
redisClient := redis.NewClient(&redis.Options{Addr: "127.0.0.1:6379"})
redisStore := store.NewRedis(redisClient, nil)
// Initialize chained cache
cacheManager := cache.NewMetric(
promMetrics,
cache.New(redisStore),
)
// Initializes marshaler
marshal := marshaler.New(cacheManager)
key := BookQuery{Slug: "my-test-amazing-book"}
value := Book{ID: 1, Name: "My test amazing book", Slug: "my-test-amazing-book"}
// Set an item in the cache and attach it a "book" tag
err = marshal.Set(key, value, store.Options{Tags: []string{"book"}})
if err != nil {
panic(err)
}
// Remove all items that have the "book" tag
err := marshal.Invalidate(store.InvalidateOptions{Tags: []string{"book"}})
if err != nil {
panic(err)
}
returnedValue, err := marshal.Get(key, new(Book))
if err != nil {
// Should be triggered because item has been deleted so it cannot be found.
panic(err)
}
Mix this with expiration times on your caches to have a fine tuned control on how your data are cached.
Write your own custom cache
Cache respect the following interface so you can write your own (proprietary?) cache logic if needed by implementing the following interface:
type CacheInterface interface {
Get(key interface{}) (interface{}, error)
Set(key, object interface{}, options *store.Options) error
Delete(key interface{}) error
Invalidate(options store.InvalidateOptions) error
Clear() error
GetType() string
}
Or, in case you use a setter cache, also implement the GetCodec() method:
type SetterCacheInterface interface {
CacheInterface
GetCodec() codec.CodecInterface
}
As all caches available in this library implement CacheInterface, you will be able to mix your own caches with your own.
Write your own custom store
You also have the ability to write your own custom store by implementing the following interface:
type StoreInterface interface {
Get(key interface{}) (interface{}, error)
Set(key interface{}, value interface{}, options *Options) error
Delete(key interface{}) error
Invalidate(options InvalidateOptions) error
Clear() error
GetType() string
}
Of course, I suggest you to have a look at current caches or stores to implement your own.
Benchmarks
Community
Please feel free to contribute on this library and do not hesitate to open an issue if you want to discuss about a feature.
Run tests
Generate mocks:
$ go get github.com/golang/mock/mockgen
$ make mocks
Test suite can be run with:
$ go test -v ./...
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