Per-namespace engines

Centrifugo OSS allows specifying an engine. Engine is responsible for PUB/SUB and channel stream/history features (we call this part Broker), and for online presence (this part is called Presence Manager). Engine in Centrifugo OSS is global for the entire Centrifugo setup – once defined, all channels use it to make operations.

Centrifugo PRO allows redefining brokers and presence managers on a namespace level. This may help with individual scaling based on channel activity, using different properties inside different channel namespaces within a single Centrifugo setup. This feature significantly enhances Centrifugo's adaptability, making it easier to meet diverse and evolving application demands.

For example, you can configure Centrifugo to use Redis engine by default, but for some specific namespace use Nats for PUB/SUB – this may be handy if you need wildcard subscriptions for one of the features in the app, or maybe you want to consume from raw Nats topics for some app feature, but for other features you still need functionality implemented by Centrifugo Redis Engine - like history in channels, automatic recovery. Or, maybe you want to separate Redis setups used for broker purposes and online presence purposes.

In general, the idea here is very similar to Granular proxy mode – configure a list of custom Brokers or Presence Managers, and then point a specific channel namespace to use it.

Defining brokers

First, you need create configuration for additional brokers:

config.json

{
  ...
  "brokers": [
    {
      "enabled": true,
      "name": "mycustomredis",
      "type": "redis",
      "redis": {
        "address": "127.0.0.1:6379"
      }
    },
    {
      "enabled": true,
      "name": "mycustomnats",
      "type": "nats",
      "nats": {
        "url": "nats://localhost:4222"
      }
    }
  ]
}

At this point Centrifugo PRO supports two broker types:

• redis - inherits all the possibilities of Centrifugo built-in Redis Engine
• nats – inherits all the possibilities of Centrifugo integration with Nats broker.

These brokers inherit all options described in Engines and scalability chapter. The only difference that it's possible to specify which custom broker to use inside a channel namespace:

config.json

{
  ...
  "namespaces": [
    {
        "name": "rates",
        "broker_name": "mycustomnats"
    }
  ]

Defining presence managers

And for custom Presence Managers a similar approach may be applied. First, define a custom presence manager:

config.json

{
  ...
  "presence_managers": [
    {
      "enabled": true,
      "name": "mycustomredis",
      "type": "redis",
      "redis": {}
    }
  ]
}

Centrifugo PRO only supports redis type of Presence Manager.

And then enable it for namespace:

config.json

{
  ...
  "namespaces": [
    {
        "name": "rates",
        "broker_name": "mycustomnats",
        "presence_manager_name": "mycustomredis"
    }
  ]