golru

golang least recently used cache

---

Basic Usage

package main

import(
  "fmt"
  "github.com/rileyr/golru/lru"
)

func main() {
  cache := lru.New(lru.WithSize(30))

  cache.Add("key", "value")
  val, ok := cache.Get("key")
  str := val.(string)

  fmt.Printf("got from cache: %s\n", str)
}

Lazy Lookup

A lookup function can be provided to the initializer. If provided, any GET misses will attempt to look up the value for the key, store it, and then return it.

package main

import(
  "fmt"
  "github.com/rileyr/golru/lru"
)

func lookup(k interface{}) (interface{}, bool) {
  // If we want to use this in front of a database, perhaps we are using the ID as the cache key:
  databaseID := k.(int)

  // Get the value from the database (or whatever):
  value := fmt.Sprintf("from-db-%d", databaseID)
  return value, true
}

func main() {
  cache := lru.New(lru.WithSize(30), lru.WithLookup(lookup))
  val, _ := cache.Get(22)
  str := val.(string)
  fmt.Printf("got from cache: %s\n", str)
}

Standalone HTTP LRU

This repo provides a standalone HTTP server that serves the cache as json. Flags that can be provided on startup:

• size: Upper limit on number of cached items. (Default 100)
• port: Port to serve the cache from. (Default :3030)
• username : BasicAuth username.
• password : BasicAuth password.

If a username and password are not provided, no authentication check will occur.

Usage:

$> go install github.com/rileyr/golru/weblru
$> weblru -port=:3015  -size=100

Requests can be made into the cache:

POST localhost:3015/cache:
{
  "key": "key",
  "value": "some value"
}
#=> 201 CREATED
#=> 400 UNPROCESSABLE ENTITY
#=> 500 INTERNAL SERVER ERROR


GET localhost:3015/cache?key=foo:
{
  "key": "key",
  "value": "some value"
}
#=> 200 FOUND
#=> 400 UNPROCESSABLE ENTITY
#=> 404 NOT FOUND
#=> 500 INTERNAL SERVER ERROR

DELETE localhost:3015/cache:
{
  "key": "key",
}

#=> 200 OK