[Redis] Django + Redis + ElastiCache

Let’s find out how to attach Redis on Django (+ElastiCache)

Get Redis

• install redis

  brew install redis

• check if it works

  ❯ redis-server
  75120:C 05 Feb 2020 13:53:59.853 # oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo
  75120:C 05 Feb 2020 13:53:59.853 # Redis version=5.0.7, bits=64, commit=00000000, modified=0, pid=75120, just started
  75120:C 05 Feb 2020 13:53:59.853 # Warning: no config file specified, using the default config. In order to specify a config file use redis-server /path/to/redis.conf
  75120:M 05 Feb 2020 13:53:59.856 * Increased maximum number of open files to 10032 (it was originally set to 256).
                  _._
             _.-``__ ''-._
        _.-``    `.  `_.  ''-._           Redis 5.0.7 (00000000/0) 64 bit
    .-`` .-```.  ```\/    _.,_ ''-._
   (    '      ,       .-`  | `,    )     Running in standalone mode
   |`-._`-...-` __...-.``-._|'` _.-'|     Port: 6379
   |    `-._   `._    /     _.-'    |     PID: 75120
    `-._    `-._  `-./  _.-'    _.-'
   |`-._`-._    `-.__.-'    _.-'_.-'|
   |    `-._`-._        _.-'_.-'    |           http://redis.io
    `-._    `-._`-.__.-'_.-'    _.-'
   |`-._`-._    `-.__.-'    _.-'_.-'|
   |    `-._`-._        _.-'_.-'    |
    `-._    `-._`-.__.-'_.-'    _.-'
        `-._    `-.__.-'    _.-'
            `-._        _.-'
                `-.__.-'
  
  75120:M 05 Feb 2020 13:53:59.857 # Server initialized
  75120:M 05 Feb 2020 13:53:59.857 * DB loaded from disk: 0.000 seconds
  75120:M 05 Feb 2020 13:53:59.858 * Ready to accept connections

  on different terminal window

  ❯ redis-cli ping
  PONG

  → it means it’s working

Specific Use for Django

pip install django-redis

# settings/base.py

CACHES = {  
    "default": {
        "BACKEND": "django_redis.cache.RedisCache",
        "LOCATION": "redis://127.0.0.1:6379/1",
        "OPTIONS": {
            "CLIENT_CLASS": "django_redis.client.DefaultClient",
        }
    }
}

Use Case as Caching

from django.core.cache import cache

cache.set('key', 'value')
foo = cache.get('key')

foo
'value'

Use ElastiCache + Redis

follow ElastiCache documentation (https://docs.aws.amazon.com/AmazonElastiCache/latest/red-ug/GettingStarted.html)

Configure everything same with ec2 instance you’re using

[Subnet Group]

[Availability zone(s)]

• You might want to recreate the cluster because the default can be different from what you already have.

[Security groups]

• Also make sure you select same security group/vpc as in your instance

Reference

https://nachwon.github.io/redis/

https://jupiny.com/2018/02/27/caching-using-redis-on-django/