Deleting a Redis Key After Time Using Golang (Detailed Guide w/ Code Examples)

Use Case(s)

In an application, you may want to store temporary data like session information, cached data, or real-time metrics in Redis. To avoid the data staying in Redis indefinitely, we can set a time-to-live (TTL) for these keys which automatically removes them after a certain period.

Code Examples

1. Setting a TTL while creating a key: Here we'll create a key with a value and set the TTL during creation.

package main

import (
	"github.com/go-redis/redis"
	"time"
)

func main() {
	client := redis.NewClient(&redis.Options{
		Addr:     "localhost:6379",
		Password: "", // no password set
		DB:       0,  // use default DB
	})

	err := client.Set("key", "value", 10*time.Second).Err()
	if err != nil {
		panic(err)
	}
}

In this example, 10*time.Second sets the TTL for 'key' to 10 seconds.

2. Setting a TTL for an existing key: We can also set a TTL for an already existing key.

package main

import (
	"github.com/go-redis/redis"
	"time"
)

func main() {
	client := redis.NewClient(&redis.Options{
		Addr:     "localhost:6379",
		Password: "", // no password set
		DB:       0,  // use default DB
	})

	_, err := client.Do("SET", "key", "value").Result()
	if err != nil {
		panic(err)
	}
	err = client.Expire("key", 10*time.Second).Err()
	if err != nil {
		panic(err)
	}
}

In this example, Expire method is used to set the TTL for 'key' to 10 seconds.

Best Practices

Remember to handle errors properly in your production code. Also, be careful with the TTL values; setting them too short might cause data to disappear before it's used, setting them too long can consume more memory than necessary.

Common Mistakes

Setting data without a proper TTL where it's required can cause the Redis instance to run out of memory. Misunderstanding the TTL as milliseconds instead of seconds is also a common mistake.

FAQs

Q: Can I view the remaining TTL of a key? A: Yes. You can use the TTL function: timeLeft, err := client.TTL("key").Result() to get the remaining time-to-live (in seconds) for the specified key.