Зачем Action Cable`у в продакшне нужен Redis?

Question

[nluparev]

В сгенерированном приложении rails версии 5.2.0 если заглянуть в Gemfile есть закоментированные строки

# Use Redis adapter to run Action Cable in production
# gem 'redis', '~> 4.0'

Может объяснить зачем Action Cable`у нужен Redis в продакшне и как он им используется?

Answer 1

[Mikhail Osher]

7.1.1 Adapter Configuration
Below is a list of the subscription adapters available for end users.

7.1.1.1 Async Adapter
The async adapter is intended for development/testing and should not be used in production.

7.1.1.2 Redis Adapter
The Redis adapter requires users to provide a URL pointing to the Redis server. Additionally, a channel_prefix may be provided to avoid channel name collisions when using the same Redis server for multiple applications. See the Redis PubSub documentation for more details.

7.1.1.3 PostgreSQL Adapter
The PostgreSQL adapter uses Active Record's connection pool, and thus the application's config/database.yml database configuration, for its connection. This may change in the future. #27214