Working with Go

Storing Objects in Memcache

How to store objects in memcache using bradfitz/gomemcache package. Memcache stores data as []byte, so you need to first encode the object prior to storing.

I typically encode using JSON, often the data is already or will soon be in JSON format, plus human readable helps debugging. If space and performance is a concern, see encoding/gob for another format.

package main
 
import (
    "encoding/json"
    "fmt"
 
    "github.com/bradfitz/gomemcache/memcache"
)
 
// define Dog object type
type Dog struct {
    Name  string
    Color string
}
 
func main() {
 
    // connect to memcache server
    mc := memcache.New("127.0.0.1:11211")
 
    // try to pull from memcache
    fetchItem, err := mc.Get("dog")
 
    // check for cache hit
    if err != memcache.ErrCacheMiss {
        if err != nil {
            fmt.Println("Error fetching from memcache", err)
        } else {
            fmt.Println("Cache hit!")
 
            dog, err := DecodeData(fetchItem.Value)
            if err != nil {
                fmt.Println("Error decoding data from memcache", err)
            } else {
                fmt.Println("Dog name is: ", dog.Name)
            }
        }
    }
 
    // create instance of object and set properties
    spot := Dog{Name: "Spot", Color: "brown"}
 
    // create memcache item to store
    setItem := memcache.Item{
        Key: "dog",
        Value: EncodeData(spot),
        Expiration: 300
    }
 
    err = mc.Set(&setItem)
    if err != nil {
        fmt.Println("Error setting memcache item", err)
    }
 
    // run twice
}
 
func DecodeData(raw []byte) (dog Dog, err error) {
    err = json.Unmarshal(raw, &dog)
    return dog, err
}
 
func EncodeData(dog Dog) []byte {
    enc, err := json.Marshal(dog)
    if err != nil {
        fmt.Println("Error encoding Action to JSON", err)
    }
    return enc
}