How-To: Scope components to one or more applications
Dapr components are namespaced (separate from the Kubernetes namespace concept), meaning a Dapr runtime instance can only access components that have been deployed to the same namespace.
Namespaces can be used to limit component access to particular Dapr instances.
Example of component namespacing in Kubernetes
Let’s consider the following component in Kubernetes:
apiVersion: dapr.io/v1alpha1 kind: Component metadata: name: statestore namespace: production spec: type: state.redis version: v1 metadata: - name: redisHost value: redis-master:6379
In this example, the Redis component is only accessible to Dapr instances running inside the
Example of component namespacing in self-hosted mode
In self hosted mode, a developer can specify the namespace to a Dapr instance by setting the
NAMESPACE environment variable.
NAMESPACE environment variable is set, Dapr will not load any component that does not specify the same namespace in its metadata.
Considering the example above, to tell Dapr which namespace it is deployed to, set the environment variable:
export NAMESPACE=production # run Dapr as usual
setx NAMESPACE "production" # run Dapr as usual
When Dapr runs, it matches it’s own configured namespace with the namespace of the components that it loads and initializes only the the one matching its namespaces. All other components in a different namespace are not loaded.
Application access to components with scopes
Developers and operators might want to limit access for one database to a certain application, or a specific set of applications.
To achieve this, Dapr allows you to specify
scopes on the component YAML. Application scopes added to a component limit only the applications with specific IDs to be able to use the component.
The following example shows how to give access to two Dapr enabled apps, with the app IDs of
app2 to the Redis component named
statestore which itself is in the
apiVersion: dapr.io/v1alpha1 kind: Component metadata: name: statestore namespace: production spec: type: state.redis version: v1 metadata: - name: redisHost value: redis-master:6379 scopes: - app1 - app2