How-To: Enable preview features

Overview

Preview features in Dapr are considered experimental when they are first released. These preview features require explicit opt-in in order to be used. The opt-in is specified in Dapr’s configuration.

Preview features are enabled on a per application basis by setting configuration when running an application instance.

Preview features

The current list of preview features can be found here.

Configuration properties

The features section under the Configuration spec contains the following properties:

Enabling a preview feature

Preview features are specified in the configuration. Here is an example of a full configuration that contains multiple features:

apiVersion: dapr.io/v1alpha1
kind: Configuration
metadata:
  name: featureconfig
spec:
  tracing:
    samplingRate: "1"
    zipkin:
      endpointAddress: "http://zipkin.default.svc.cluster.local:9411/api/v2/spans"
  features:
    - name: Feature1
      enabled: true
    - name: Feature2
      enabled: true

Standalone

To enable preview features when running Dapr locally, either update the default configuration or specify a separate config file using dapr run.

The default Dapr config is created when you run dapr init, and is located at:

• Windows: %USERPROFILE%\.dapr\config.yaml
• Linux/macOS: ~/.dapr/config.yaml

Alternately, you can update preview features on all apps run locally by specifying the --config flag in dapr run and pointing to a separate Dapr config file:

dapr run --app-id myApp --config ./previewConfig.yaml ./app

Kubernetes

In Kubernetes mode, the configuration must be provided via a configuration component. Using the same configuration as above, apply it via kubectl:

kubectl apply -f previewConfig.yaml

This configuration component can then be referenced in any application by modifying the application’s configuration to reference that specific configuration component via the dapr.io/config element. 例如：

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nodeapp
  labels:
    app: node
spec:
  replicas: 1
  selector:
    matchLabels:
      app: node
  template:
    metadata:
      labels:
        app: node
      annotations:
        dapr.io/enabled: "true"
        dapr.io/app-id: "nodeapp"
        dapr.io/app-port: "3000"
        dapr.io/config: "featureconfig"
    spec:
      containers:
      - name: node
        image: dapriosamples/hello-k8s-node:latest
        ports:
        - containerPort: 3000
        imagePullPolicy: Always