Initial commit

README.md

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+CacheInterface
+--------------
+
+An experimental interface to use different caches interchangeably via URIs
+
+Example Cache URIs:
+
+```
+redis://server:port?db=0&password=test
+memcache://server1:11211,server2:11211
+```
+
+Code
+####
+
+The CacheInterface interface has all methods. All clients will implement this on a best-effort basis.
+
+```go
+type CacheInterface interface {
+	Has(key string) bool
+	Get(key string) ([]byte, error)
+	Set(key string, val interface{}, ttl time.Duration) (err error)
+	Del(key string) error
+}
+```
+Note: Set will automatically attempt to store byte arrays and strings directly, and encode the rest with JSON.

cache.go

@@ -0,0 +1,48 @@
+package cache
+
+import (
+	"errors"
+	"net/url"
+	"strings"
+	"time"
+)
+
+const (
+	Memcache = "memcache"
+	Redis    = "redis"
+)
+
+var (
+	ErrInvalidDriver = errors.New("invalid driver")
+)
+
+type CacheInterface interface {
+	Has(key string) bool
+	Get(key string) ([]byte, error)
+	Set(key string, val interface{}, ttl time.Duration) (err error)
+	Del(key string) error
+}
+
+func New(uri string) (CacheInterface, error) {
+	u, err := url.Parse(uri)
+
+	if err != nil {
+		return nil, err
+	}
+
+	query := u.Query()
+
+	switch u.Scheme {
+	case Redis:
+		return NewRedisCache(RedisSettings{
+			Address:  u.Host,
+			Password: query.Get("password"),
+		})
+	case Memcache:
+		return NewMemcacheCache(MemcacheSettings{
+			Servers: strings.Split(u.Host, ","),
+		})
+	}
+
+	return nil, ErrInvalidDriver
+}

cache_memcache.go

@@ -0,0 +1,63 @@
+package cache
+
+import (
+	"encoding/json"
+	"github.com/bradfitz/gomemcache/memcache"
+	"time"
+)
+
+type MemcacheSettings struct {
+	Servers []string
+}
+
+type MemcacheCache struct {
+	backend *memcache.Client
+}
+
+func NewMemcacheCache(s MemcacheSettings) (CacheInterface, error) {
+	c := memcache.New(s.Servers...)
+
+	return &MemcacheCache{
+		backend: c,
+	}, nil
+}
+
+func (mc *MemcacheCache) Has(key string) bool {
+	_, err := mc.backend.Get(key)
+
+	return err != nil
+}
+
+func (mc *MemcacheCache) Get(key string) ([]byte, error) {
+	item, err := mc.backend.Get(key)
+
+	if err != nil {
+		return nil, err
+	}
+
+	return item.Value, nil
+}
+
+func (mc *MemcacheCache) Set(key string, val interface{}, ttl time.Duration) error {
+	var v []byte
+
+	if b, ok := val.([]byte); ok {
+		v = b
+	} else if s, ok := val.(string); ok {
+		b = []byte(s)
+	} else {
+		b, err := json.Marshal(val)
+
+		if err != nil {
+			return err
+		}
+
+		v = b
+	}
+
+	return mc.backend.Set(&memcache.Item{Key: key, Value: v, Expiration: int32(ttl.Seconds())})
+}
+
+func (mc *MemcacheCache) Del(key string) error {
+	return mc.backend.Delete(key)
+}

cache_redis.go

@@ -0,0 +1,62 @@
+package cache
+
+import (
+	"encoding/json"
+	"github.com/hoisie/redis"
+	"time"
+)
+
+type RedisSettings struct {
+	Address  string
+	DB       int
+	Password string
+}
+
+type RedisCache struct {
+	CacheInterface
+
+	c *redis.Client
+}
+
+func NewRedisCache(c RedisSettings) (CacheInterface, error) {
+	rc := &redis.Client{Addr: c.Address, Db: c.DB, Password: c.Password}
+
+	return &RedisCache{
+		c: rc,
+	}, nil
+}
+
+func (rc *RedisCache) Has(key string) bool {
+	b, _ := rc.c.Exists(key)
+	return b
+}
+
+func (rc *RedisCache) Get(key string) ([]byte, error) {
+	return rc.c.Get(key)
+}
+
+func (rc *RedisCache) Set(key string, val interface{}, ttl time.Duration) error {
+	var v []byte
+
+	if b, ok := val.([]byte); ok {
+		v = b
+	} else if s, ok := val.(string); ok {
+		b = []byte(s)
+	} else {
+		b, err := json.Marshal(val)
+
+		if err != nil {
+			return err
+		}
+
+		v = b
+	}
+
+	return rc.c.Setex(key, int64(ttl.Seconds()), v)
+}
+
+func (rc *RedisCache) Del(key string) error {
+	_, err := rc.c.Del(key)
+
+	return err
+}

go.mod

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+module meow.tf/go/cacheinterface
+
+go 1.12
+
+require (
+	github.com/bradfitz/gomemcache v0.0.0-20190913173617-a41fca850d0b
+	github.com/hoisie/redis v0.0.0-20160730154456-b5c6e81454e0
+)

go.sum

@@ -0,0 +1,4 @@
+github.com/bradfitz/gomemcache v0.0.0-20190913173617-a41fca850d0b h1:L/QXpzIa3pOvUGt1D1lA5KjYhPBAN/3iWdP7xeFS9F0=
+github.com/bradfitz/gomemcache v0.0.0-20190913173617-a41fca850d0b/go.mod h1:H0wQNHz2YrLsuXOZozoeDmnHXkNCRmMW0gwFWDfEZDA=
+github.com/hoisie/redis v0.0.0-20160730154456-b5c6e81454e0 h1:mjZV3MTu2A5gwfT5G9IIiLGdwZNciyVq5qqnmJJZ2JI=
+github.com/hoisie/redis v0.0.0-20160730154456-b5c6e81454e0/go.mod h1:pMYMxVaKJqCDC1JUg/XbPJ4/fSazB25zORpFzqsIGIc=