[1.18] feat(config): add config map as configuration

daprdocs/content/en/reference/components-reference/supported-configuration-stores/kubernetes-configmap-configuration-store.md

@@ -0,0 +1,157 @@
+---
+type: docs
+title: "Kubernetes ConfigMap"
+linkTitle: "Kubernetes ConfigMap"
+description: Detailed information on the Kubernetes ConfigMap configuration store component
+---
+
+## Component format
+
+To set up a Kubernetes ConfigMap configuration store, create a component of type `configuration.kubernetes`. See [this guide]({{% ref "howto-manage-configuration.md#configure-a-dapr-configuration-store" %}}) on how to create and apply a configuration store configuration.
+
+```yaml
+apiVersion: dapr.io/v1alpha1
+kind: Component
+metadata:
+  name: <NAME>
+spec:
+  type: configuration.kubernetes
+  version: v1
+  metadata:
+  - name: configMapName
+    value: "<CONFIGMAP_NAME>"
+  # Optional: path to kubeconfig (only needed when running outside the cluster)
+  #- name: kubeconfigPath
+  #  value: "/path/to/kubeconfig"
+  # Optional: informer resync period
+  #- name: resyncPeriod
+  #  value: "0"
+```
+
+## Spec metadata fields
+
+| Field | Required | Details | Example |
+|-------|:--------:|---------|---------|
+| `configMapName` | Y | The name of the Kubernetes ConfigMap to use as the configuration source. Must be a valid [RFC 1123](https://kubernetes.io/docs/concepts/overview/working-with-objects/names/#dns-label-names) DNS label name. | `"my-app-config"` |
+| `kubeconfigPath` | N | Path to a kubeconfig file. When running inside a Kubernetes cluster (the typical case), this is not needed. When running outside the cluster, it falls back to the `KUBECONFIG` environment variable, then to `~/.kube/config`. | `"/path/to/kubeconfig"` |
+| `resyncPeriod` | N | How often the informer fully re-syncs the ConfigMap state from the API server as a consistency safety net, independent of watch events. Set to `"0"` (default) to disable periodic resync and rely solely on watch events. | `"10m"` |
+
+## Set up a Kubernetes ConfigMap as Configuration Store
+
+The Kubernetes ConfigMap configuration store requires no external infrastructure beyond the Kubernetes cluster itself.
+
+### Prerequisites
+
+- A running Kubernetes cluster
+- The Dapr sidecar must have RBAC permissions to `get`, `list`, and `watch` ConfigMaps in the target namespace
+
+### 1. Create the ConfigMap
+
+Create a ConfigMap that holds your configuration data:
+
+```bash
+kubectl create configmap my-app-config \
+  --from-literal=log.level=info \
+  --from-literal=feature.enable-v2=true \
+  --from-literal=database.pool-size=10
+```
+
+Or using a YAML manifest:
+
+```yaml
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: my-app-config
+  namespace: default
+data:
+  log.level: "info"
+  feature.enable-v2: "true"
+  database.pool-size: "10"
+```
+
+### 2. Configure RBAC
+
+The Dapr sidecar's service account needs permission to access ConfigMaps. Create a Role and RoleBinding:
+
+```yaml
+apiVersion: rbac.authorization.k8s.io/v1
+kind: Role
+metadata:
+  name: dapr-configmap-reader
+  namespace: default
+rules:
+- apiGroups: [""]
+  resources: ["configmaps"]
+  verbs: ["get", "list", "watch"]
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: RoleBinding
+metadata:
+  name: dapr-configmap-reader-binding
+  namespace: default
+subjects:
+- kind: ServiceAccount
+  name: default
+  namespace: default
+roleRef:
+  kind: Role
+  name: dapr-configmap-reader
+  apiGroup: rbac.authorization.k8s.io
+```
+
+{{% alert title="Note" color="primary" %}}
+If you installed Dapr using the Helm chart with default settings, the Dapr sidecar service account may already have sufficient permissions. Verify your cluster's RBAC configuration.
+{{% /alert %}}
+
+### 3. Apply the component
+
+Apply the Dapr component configuration:
+
+```yaml
+apiVersion: dapr.io/v1alpha1
+kind: Component
+metadata:
+  name: myconfigstore
+spec:
+  type: configuration.kubernetes
+  version: v1
+  metadata:
+  - name: configMapName
+    value: "my-app-config"
+```
+
+## How it works
+
+### Data model
+
+Each key in the ConfigMap's `data` field becomes a configuration item. The ConfigMap's `resourceVersion` (assigned by Kubernetes) is used as the version for all items.
+
+Keys in the `binaryData` field are also supported. Their values are returned as base64-encoded strings with `"encoding": "base64"` in the item metadata.
+
+### Subscriptions
+
+When you subscribe to configuration changes, the component uses a [Kubernetes SharedIndexInformer](https://pkg.go.dev/k8s.io/client-go/tools/cache#SharedIndexInformer) with a field selector scoped to the specific ConfigMap. This means:
+
+- Only changes to the watched ConfigMap generate API traffic
+- Changes are detected in near real-time via the Kubernetes watch API
+- Only changed keys are included in update notifications
+
+When a key is deleted from the ConfigMap, the notification includes `"deleted": "true"` in the item's metadata with an empty value.
+
+### Namespace
+
+The component watches ConfigMaps in the same namespace as the Dapr sidecar. The namespace is derived from the `NAMESPACE` environment variable, which is automatically set by the Dapr sidecar injector via the Kubernetes downward API. If the variable is not set, the component defaults to `"default"`.
+
+Cross-namespace ConfigMap access is not supported. This is by design to maintain Kubernetes namespace security boundaries.
+
+{{% alert title="Note" color="primary" %}}
+ConfigMaps are not encrypted at rest by default in Kubernetes. Do not store sensitive values (passwords, API keys, tokens) in ConfigMaps. Use [Kubernetes Secrets]({{% ref "kubernetes-secret-store" %}}) or a dedicated secret store instead.
+{{% /alert %}}
+
+## Related links
+
+- [Basic schema for a Dapr component]({{% ref component-schema %}})
+- [Configuration building block]({{% ref configuration-api-overview %}})
+- Read [How-To: Manage configuration from a store]({{% ref "howto-manage-configuration" %}}) for instructions on how to use a configuration store.
+- [Kubernetes ConfigMap documentation](https://kubernetes.io/docs/concepts/configuration/configmap/)

daprdocs/data/components/configuration_stores/generic.yaml

@@ -7,4 +7,9 @@
   link: postgresql-configuration-store
   state: Stable
   version: v1
-  since: "1.11"
+  since: "1.11"
+- component: Kubernetes ConfigMap
+  link: kubernetes-configmap-configuration-store
+  state: Alpha
+  version: v1
+  since: "1.17"