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Setup a pub/sub component
Dapr integrates with pub/sub message buses to provide apps with the ability to create event-driven, loosely coupled architectures where producers send events to consumers via topics.
Dapr supports the configuration of multiple, named, pub/sub components per application. Each pub/sub component has a name and this name is used when publishing a message topic
Pub/Sub message buses are extensible and can be found in the components-contrib repo.
A pub/sub in Dapr is described using a Component file:
apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
name: pubsub
namespace: default
spec:
type: pubsub.<NAME>
metadata:
- name: <KEY>
value: <VALUE>
- name: <KEY>
value: <VALUE>
...
The type of pub/sub is determined by the type field, and things like connection strings and other metadata are put in the .metadata section.
Even though you can put plain text secrets in there, it is recommended you use a secret store using a secretKeyRef
Running locally
When running locally with the Dapr CLI, a component file for a Redis pub/sub is created in a components directory, which for Linux/MacOS is $HOME/.dapr/components and for Windows is %USERPROFILE%\.dapr\components. See Environment Setup
You can make changes to this file the way you see fit, whether to change connection values or replace it with a different pub/sub.
Running in Kubernetes
Dapr uses a Kubernetes Operator to update the sidecars running in the cluster with different components.
To setup a pub/sub in Kubernetes, use kubectl to apply the component file:
kubectl apply -f pubsub.yaml