cache.go

package cache

import (
	"fmt"
	"time"

	"git.perx.ru/perxis/perxis-go/pkg/service"
	lru "github.com/hashicorp/golang-lru/v2"
	"go.uber.org/zap"
)

const (
	defaultCacheSize = 1000
	defaultTTL       = 30 * time.Second
)

type Cache interface {
	Set(key, value any) error
	Get(key any) (any, error)
	Remove(key any) error
}

var _ Cache = &MemoryCache{}

type MemoryCache struct {
	cache  *lru.Cache[interface{}, interface{}]
	ttl    time.Duration
	logger *zap.Logger
}

type item struct {
	value     interface{}
	expiredAt time.Time
}

func NewCache(size int, ttl time.Duration, opts ...interface{}) *MemoryCache {
	if size == 0 {
		size = defaultCacheSize
	}
	if ttl == 0 {
		ttl = defaultTTL
	}
	c, err := lru.New[interface{}, interface{}](size)
	if err != nil {
		panic(err)
	}
	ch := &MemoryCache{
		cache:  c,
		ttl:    ttl,
		logger: zap.NewNop(),
	}

	for _, o := range opts {
		switch p := o.(type) {
		case *zap.Logger:
			ch.logger = p
		}
	}

	ch.logger = ch.logger.Named("Cache")

	return ch
}

func (c *MemoryCache) Set(key, value interface{}) (err error) {
	c.cache.Add(key, &item{value: value, expiredAt: time.Now().Add(c.ttl)})
	c.logger.Debug("Set", zap.String("key", fmt.Sprintf("%v", key)), zap.String("ptr", fmt.Sprintf("%p", value)))
	return nil
}

func (c *MemoryCache) Get(key interface{}) (value interface{}, err error) {
	val, ok := c.cache.Get(key)
	if ok {
		v := val.(*item)
		if v.expiredAt.Before(time.Now()) {
			_ = c.Remove(key)
			c.logger.Debug("Expired", zap.String("key", fmt.Sprintf("%v", key)), zap.String("ptr", fmt.Sprintf("%p", v.value)))
			return nil, service.ErrNotFound
		}
		c.logger.Debug("Hit", zap.String("key", fmt.Sprintf("%v", key)), zap.String("ptr", fmt.Sprintf("%p", v.value)))
		return v.value, nil
	}
	c.logger.Debug("Miss", zap.String("key", fmt.Sprintf("%v", key)))
	return nil, service.ErrNotFound
}

func (c *MemoryCache) Remove(key interface{}) (err error) {
	present := c.cache.Remove(key)
	c.logger.Debug("Remove", zap.String("key", fmt.Sprintf("%v", key)))

	if !present {
		err = service.ErrNotFound
	}

	return
}