lru

A lru is an asynchronous LRU cache (generic version).

• based on golang map structure
• prevents infinite cache growth
• designed for asynchronous use

Usage

For example, caching the output of the ioutil.ReadFile function to reduce disk I/O.

package main
import (
    "log"
    "os"
    "github.com/codeation/lru"
)
func readFileContent(key string) ([]byte, error) {
    log.Println("read once")
    return os.ReadFile(key)
}
func main() {
    cache := lru.NewSyncLRU(1024, readFileContent)
    for i := 0; i < 10; i++ {
        data, err := cache.Get("input.txt")
        if err != nil {
            log.Fatal(err)
        }
        log.Printf("file size is %d\n", len(data))
    }
}

The lru.NewSyncLRU parameter is the number of cache items until the last used item is removed from the cache. The second parameter is a func to get the value for the specified key and error.

The parameter of cache.Get func is a key (filename in this case). An error is returned when the function returns an error.