go-cache is an in-memory key:value store/cache similar to memcached that is suitable for
applications running on a single machine. Any object can be stored, for a given duration
or forever, and the cache can be used safely by multiple goroutines.

Installation:
    goinstall github.com/pmylund/go-cache

Usage:
    // Create a cache with a default expiration time of 5 minutes, and which purges
    // expired items every 30 seconds
    c := cache.New(5*time.Minute, 30*time.Second)

    // Set the value of the key "foo" to "bar", with the default expiration time
    c.Set("foo", "bar", 0)

    // Set the value of the key "baz" to "yes", with no expiration time (the item
    // won't be removed until it is re-set, or removed using c.Delete("baz")
    c.Set("baz", "yes", -1)

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

    // Since Go is statically typed, and cache values can be anything, type assertion
    // is needed when values are being passed to functions that don't take arbitrary types,
    // (i.e. interface{}). The simplest way to do this for values which will only be used
    // once--e.g. for passing to another function--is:
    foo, found := c.Get("foo")
    if found {
            MyFunction(foo.(string))
    }

    // This gets tedious if the value is used several times in the same function. You
    // might do either of the following instead:
    if x, found := c.Get("foo"); found {
            foo := x.(string)
            ...
    }
    // or
    var foo string
    if x, found := c.Get("foo"); found {
            foo = x.(string)
    }
    ...
    // foo can then be passed around freely as a string

    // Want performance? Store pointers!
    c.Set("foo", &MyStruct, 0)
    if x, found := c.Get("foo"); found {
            foo := x.(*MyStruct)
            ...
    }

If you store a reference type like a pointer, slice, map or channel, you do not need to
run Set if you modify the underlying data. The cache does not serialize its data, so if
you modify a struct whose pointer you've stored in the cache, retrieving that pointer
with Get will point you to the same data:

    foo := &MyStruct{Num: 1}
    c.Set("foo", foo, 0)
    ...
    x, _ := c.Get("foo")
    foo := x.(MyStruct)
    fmt.Println(foo.Num)
    ...
    foo.Num++
    ...
    x, _ := c.Get("foo")
    foo := x.(MyStruct)
    foo.Println(foo.Num)

will print:
    1
    2