github.com/cozy/cozy-stack@v0.0.0-20240603063001-31110fa4cae1/pkg/limits/impl_redis.go (about) 1 package limits 2 3 import ( 4 "context" 5 "strconv" 6 "time" 7 8 "github.com/redis/go-redis/v9" 9 ) 10 11 // Redis implementation of [Counter]. 12 // 13 // This implementation is safe to use in multi-instances installation. 14 type Redis struct { 15 Client redis.UniversalClient 16 ctx context.Context 17 } 18 19 // NewRedis returns a counter that can be mutualized between several 20 // cozy-stack processes by using redis. 21 func NewRedis(client redis.UniversalClient) Counter { 22 return &Redis{client, context.Background()} 23 } 24 25 // incrWithTTL is a lua script for redis to increment a counter and sets a TTL 26 // if it doesn't have one. 27 const incrWithTTL = ` 28 local n = redis.call("INCR", KEYS[1]) 29 if redis.call("TTL", KEYS[1]) == -1 then 30 redis.call("EXPIRE", KEYS[1], KEYS[2]) 31 end 32 return n 33 ` 34 35 func (r *Redis) Increment(key string, timeLimit time.Duration) (int64, error) { 36 ttl := strconv.FormatInt(int64(timeLimit/time.Second), 10) 37 count, err := r.Client.Eval(r.ctx, incrWithTTL, []string{key, ttl}).Result() 38 if err != nil { 39 return 0, err 40 } 41 return count.(int64), nil 42 } 43 44 func (r *Redis) Reset(key string) error { 45 _, err := r.Client.Del(r.ctx, key).Result() 46 return err 47 }