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go-cache/README.md

5.5 KiB

go-cache

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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