Configuration and use of REDIS

Introducing REDIS

Redis (REmote DIctionary Server) is an extremely fast NoSQL key-value database, mainly used as a cache, queue and message engine. It operates in memory (RAM), which enables it to offer much better performance than traditional databases for certain tasks.

In Pod, REDIS is used as a :

• cache manager for Web servers,
• encoding/transcription/xAPI task queue manager for encoding servers, in addition to Celery. Only in the case of remote encoding on other servers (notion of Celery Broker)_.

At present, it is an essential building block for the operation of Pod.

REDIS configuration for Pod

List of useful databases

Base identifier	Comments
2	Base for the select2 plugin (useful for selection lists)
3	Base for the backend
4	Base for sessions
5	Base for encoding and transcoding
6	Base for xAPI

Effective configuration

Configuration is carried out in your custom/settings_local.py file:

# To use traditional remote encoding
CELERY_TO_ENCODE = True
# REDIS broker URL
CELERY_BROKER_URL = "redis://127.0.0.1:6379/5"
# Allows only one task to be processed at a time
CELERY_TASK_ACKS_LATE = True
# Cache management
CACHES = {
  'default': {
    'BACKEND': 'django_redis.cache.RedisCache',
    'LOCATION': 'redis://127.0.0.1:6379/3',
    'OPTIONS': {
      'CLIENT_CLASS': 'django_redis.client.DefaultClient',
    },
  },
  'select2': {
    'BACKEND': 'django_redis.cache.RedisCache',
    'LOCATION': 'redis://127.0.0.1:6379/2',
    'OPTIONS': {
      'CLIENT_CLASS': 'django_redis.client.DefaultClient',
    },
  },
}
SESSION_ENGINE = 'redis_sessions.session'
SESSION_REDIS = {
  'host': '127.0.0.1',
  'port': 6379,
  'db': 4,
  'prefix': 'session',
  'socket_timeout': 1,
  'retry_on_timeout': False
}
# Tell select2 which cache configuration to use
SELECT2_CACHE_BACKEND = "select2"

⚠️ Depending on your architecture, remember to replace 127.0.0.1 with the IP address of the REDIS server, see installation documentation.