go-cache/README.md

go-cache

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ℹ️ go-cache is a port of great go-cache library that was written by @patrickmn. The main defference is that it relies on generics instead of reflection.

go-cache is a in-memory key:value store/cache similar to memcached that is suitable for applications running on a single machine. Its major advantage is that, being essentially a thread-safe map[string][T] with expiration times, it doesn't need to serialize or transmit its contents over the network.

Any object can be stored, for a given duration or forever, and the cache can be safely used by multiple goroutines.

Although go-cache isn't meant to be used as a persistent datastore, the entire cache can be saved to and loaded from a file (using c.Items() to retrieve the items map to serialize, and NewFrom() to create a cache from a deserialized one) to recover from downtime quickly. (See the docs for NewFrom() for caveats.)

Installation

go get github.com/num30/go-cache

Usage

import (
	"fmt"
	"github.com/num30/go-cache"
	"time"
)

func main() {
	// Create a cache with a default expiration time of 5 minutes, and which
	// purges expired items every 10 minutes
	c := cache.New[string](5*time.Minute, 10*time.Minute)

	// Set the value of the key "foo" to "bar", with the default expiration time
	c.Set("foo", "bar", cache.DefaultExpiration)

	// Set the value of the key "baz" to "lightning", with no expiration time
	// (the item won't be removed until it is re-set, or removed using
	// c.Delete("baz")
	c.Set("baz", "lightning", cache.NoExpiration)

	// Get the string associated with the key "foo" from the cache
	foo, found := c.Get("foo")
	if found {
		fmt.Println(foo)
	}

	// Want performance? Store pointers!
	structCache := cache.New[MyStruct](5*time.Minute, 10*time.Minute)
	structCache.Set("foo", &MyStruct, cache.DefaultExpiration)
	if x, found := c.Get("foo"); found {
		fmt.Println(")
	}
}

Run this example with go run examples/main.go.

Performance Comparison

Comparison of performance with original go-cache implementation.

Spoiler alert! The difference is insignificant.

Test	Non generic		This version
BenchmarkCacheGetStringExpiring-8	29884011	41.45 ns/op	28318041	43.31 ns/op
BenchmarkCacheGetStringNotExpiring-8	91891774	14.20 ns/op	72259294	14.02 ns/op
BenchmarkCacheGetConcurrentExpiring-8	26299849	42.58 ns/op	30129078	39.53 ns/op
BenchmarkCacheGetConcurrentNotExpiring-8	28991383	41.25 ns/op	30760544	38.09 ns/op
BenchmarkCacheGetManyConcurrentExpiring-8	55589712	44.90 ns/op	56991110	38.86 ns/op
BenchmarkCacheGetManyConcurrentNotExpiring-8	30105078	43.98 ns/op	46270045	41.54 ns/op
BenchmarkCacheSetStringExpiring-8	18392893	63.41 ns/op	17788724	61.42 ns/op
BenchmarkCacheSetStringNotExpiring-8	46400654	28.45 ns/op	40226074	27.41 ns/op
BenchmarkCacheSetDelete-8	18703620	60.75 ns/op	18270448	59.90 ns/op
BenchmarkCacheSetDeleteSingleLock-8	32633755	39.34 ns/op	32415156	36.96 ns/op
BenchmarkCacheGetStructExpiring-8	30487856	41.60 ns/op	26925226	40.55 ns/op
BenchmarkCacheGetStructNotExpiring-8	91921044	13.94 ns/op	96379750	13.08 ns/op
BenchmarkCacheSetStructExpiring-8	13977464	86.44 ns/op	13364509	87.69 ns/op
BenchmarkCacheSetStructNotExpiring-8	22749384	54.14 ns/op	23207397	52.58 ns/op
BenchmarkCacheSetFatStructExpiring-8	11718718	103.3 ns/op	12051895	102.3 ns/op
BenchmarkCacheGetFatStructNotExpiring-8	88695709	13.92 ns/op	83220014	13.76 ns/op