linstrom/storage/cache/cache.go

package cache

import (
	"context"
	"fmt"
	"time"

	"github.com/dgraph-io/ristretto"
	"github.com/eko/gocache/lib/v4/cache"
	"github.com/eko/gocache/lib/v4/store"
	redis_store "github.com/eko/gocache/store/redis/v4"
	ristretto_store "github.com/eko/gocache/store/ristretto/v4"
	"github.com/redis/go-redis/v9"
	"github.com/rs/zerolog/log"
	"gitlab.com/mstarongitlab/linstrom/config"
)

type Cache struct {
	cache    *cache.ChainCache[[]byte]
	decoders *DecoderPool
	encoders *EncoderPool
}

var ctxBackground = context.Background()

// TODO: Maybe also include metrics
func NewCache(maxSize int64, redisUrl *string) (*Cache, error) {
	// ristretto is an in-memory cache
	log.Debug().Int64("max-size", maxSize).Msg("Setting up ristretto")
	ristrettoCache, err := ristretto.NewCache(&ristretto.Config{
		// The *10 is a recommendation from ristretto
		NumCounters: maxSize * 10,
		MaxCost:     maxSize,
		BufferItems: 64, // Same here
	})
	if err != nil {
		return nil, fmt.Errorf("ristretto cache error: %w", err)
	}
	ristrettoStore := ristretto_store.NewRistretto(
		ristrettoCache,
		store.WithExpiration(
			time.Second*time.Duration(config.GlobalConfig.Storage.MaxInMemoryCacheSize),
		),
	)

	var cacheManager *cache.ChainCache[[]byte]
	if redisUrl != nil {
		opts, err := redis.ParseURL(*redisUrl)
		if err != nil {
			return nil, err
		}
		redisClient := redis.NewClient(opts)
		redisStore := redis_store.NewRedis(
			redisClient,
			store.WithExpiration(
				time.Second*time.Duration(*config.GlobalConfig.Storage.MaxRedisCacheTTL),
			),
		)
		cacheManager = cache.NewChain(
			cache.New[[]byte](ristrettoStore),
			cache.New[[]byte](redisStore),
		)
	} else {
		cacheManager = cache.NewChain(cache.New[[]byte](ristrettoStore))
	}

	return &Cache{
		cache:    cacheManager,
		decoders: NewDecoderPool(),
		encoders: NewEncoderPool(),
	}, nil
}

func (c *Cache) Get(key string, target any) (bool, error) {
	data, err := c.cache.Get(ctxBackground, key)
	if err != nil {
		return false, err
	}
	err = c.decoders.Decode(data, target)
	if err != nil {
		return false, err
	}
	return true, err
}

func (c *Cache) Set(key string, value any) error {
	data, err := c.encoders.Encode(value)
	if err != nil {
		return err
	}
	err = c.cache.Set(ctxBackground, key, data, nil)
	return err
}

func (c *Cache) Delete(key string) {
	// Error return doesn't matter here. Delete is delete is gone
	_ = c.cache.Delete(ctxBackground, key)
}