缓存

go-cache是​​内存中的键：类似于memcached的值存储/缓存，适用于在一台计算机上运行的应用程序。它的主要优点是，由于本质上是map[string]interface{}具有到期时间的线程安全的，因此不需要通过网络序列化或传输其内容。

可以在给定的持续时间内或永久存储任何对象，并且可以由多个goroutine安全使用缓存。

尽管不打算将go-cache用作持久性数据存储，但可以将整个缓存保存到文件中并从文件中加载（c.Items()用于检索要映射的项目映射并NewFrom()从反序列化的缓存中创建缓存）以进行恢复从停机时间很快。（有关NewFrom()警告，请参阅文档。）

安装

import (
    "fmt"
    "github.com/patrickmn/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(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 42, with no expiration time
    // (the item won't be removed until it is re-set, or removed using
    // c.Delete("baz")
    c.Set("baz", 42, cache.NoExpiration)

    // 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, cache.DefaultExpiration)
    if x, found := c.Get("foo"); found {
        foo := x.(*MyStruct)
            // ...
    }
}