Detailed explanation of the introduction to go memory cache BigCache

1. Introduction

bigcache is a memory cache system that stores key-value pair data. No gc operation. When using it, serialization (inverse).
The source code of bigcache is/allegro/bigcacheSeveral features are stored through []byte, without expiration time.

2. Installation

We install the latest v3 version

go get -u /allegro/bigcache/v3

After the installation is complete, we can use bigcache in the go language. Here are some simple examples.

3. Use examples

func TestSetGet(t *) {
    // new a bigCache object    cache, _ := ((), (10*))

    // get a valueless key    vNil, err := ("key")
    (vNil, err) // [] Entry not found [] byte slice with empty value
    // set    ("key", []byte("value"))
    // get    v, _ := ("key")
    (v)         // Output [118 97 108 117 101]    (string(v)) // Output value}

Let's take a look at the source code of Set and Get methods

// Set saves entry under the key
func (c *BigCache) Set(key string, entry []byte) error {
    hashedKey := .Sum64(key)
    shard := (hashedKey)
    return (key, hashedKey, entry)
}

// Get reads entry for the key.
// It returns an ErrEntryNotFound when
// no entry exists for the given key.
func (c *BigCache) Get(key string) ([]byte, error) {
    hashedKey := .Sum64(key)
    shard := (hashedKey)
    return (key, hashedKey)
}

In the Set() method, the stored value is[]byteByte slice type, so when we save it, we need to serialize the data into[]byte。
And in the Get() method, the obtained value is[]byte,We need to deserialize[]byteTo the original type.

3. 1 string type storage, acquisition and modification

The string type can be converted using []byte and type, which is convenient for each other.

func TestSetGet(t *) {
    // new a bigCache object    cache, _ := ((), (10*))
    // get a valueless key    vNil, err := ("key")
    (vNil, err) // [] Entry not found [] byte slice with empty value    // set    ("key", []byte("value"))
    // get    v, _ := ("key")
    (v)         // Output [118 97 108 117 101]    (string(v)) // Output value}

3.2 Storage, acquisition and modification of non-string types

It is not a string type, converted to []byte, which is quite complicated. Among the built-in libraries in go, the only json library provides such a method. You can convert any type that is not string to []byte, as follows.

func Marshal(v any) ([]byte, error) // Serializationfunc Unmarshal(data []byte, v any) error // Deserialization

Here we also use json's serialization (anti) method to convert it with []byte.

3. 2. 1. Storage, acquisition and modification of slice types

// TestSetGetSlice slice typefunc TestSetGetSlice(t *) {
    // new a bigCache object    cache, _ := ((), (10*))
    // slice store data    s := []string{"1", "2"}
    bs, _ := (s)
    ("s", bs)
    // get the value    bsv, _ := ("s")
    var s2 []string = make([]string, 0)
    _ = (bsv, &amp;s2)
    (s2)
    // Modify data, modify s2 to see if it will affect the value in memory    // The answer is that it will not affect    s2 = append(s2, "3")
    (s2)
    var s3 []string = make([]string, 0)
    _ = (bsv, &amp;s3)
    (s3)
}

3. 2. 2. 2. 2 struct structure type storage, acquisition and modification

// TestSetGetStruct Struct Pointerfunc TestSetGetStruct(t *) {
    // new a bigCache object    cache, _ := ((), (10*))
    // Structure struct stores data    type st struct {
        Value string
    }
    s := &amp;st{
        Value: "v1",
    }
    bs, _ := (s)
    ("s", bs)
    // get the value    bsv, _ := ("s")
    var s2 st
    _ = (bsv, &amp;s2)
    (s2) // {v1}
    // Modify data, modify s2 to see if it will affect the value in memory    // The answer is that it will not affect     = "v2"
    (s2) // {v2}
    var s3 st
    _ = (bsv, &amp;s3)
    (s3) // {v1}
}

in conclusion

Bigcache can be used safely, and after modification and acquisition, it will not affect the original value in memory.

The above is the detailed explanation of the introduction to the use of go memory cache BigCache. For more information about go memory cache BigCache, please follow my other related articles!