docs/daprdocs/content/en/reference/resource-specs/component-schema.md

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---
type: docs
title: "Component spec"
linkTitle: "Component"
weight: 1000
description: "The basic spec for a Dapr component"
---
Dapr defines and registers components using a [resource specifications](https://kubernetes.io/docs/tasks/extend-kubernetes/custom-resources/custom-resource-definitions/). All components are defined as a resource and can be applied to any hosting environment where Dapr is running, not just Kubernetes.
## Format
```yaml
apiVersion: dapr.io/v1alpha1
kind: Component
auth:
secretstore: [SECRET-STORE-NAME]
metadata:
name: [COMPONENT-NAME]
namespace: [COMPONENT-NAMESPACE]
spec:
type: [COMPONENT-TYPE]
version: v1
initTimeout: [TIMEOUT-DURATION]
ignoreErrors: [BOOLEAN]
metadata:
- name: [METADATA-NAME]
value: [METADATA-VALUE]
scopes:
- [APPID]
- [APPID]
```
## Spec fields
| Field | Required | Details | Example |
|--------------------|:--------:|---------|---------|
| apiVersion | Y | The version of the Dapr (and Kubernetes if applicable) API you are calling | `dapr.io/v1alpha1`
| kind | Y | The type of resource. For components is must always be `Component` | `Component`
| auth | N | The name of a secret store where `secretKeyRef` in the metadata lookup the name of secrets used in the component | See [How-to: Reference secrets in components]({{< ref component-secrets >}})
| scopes | N | The applications the component is limited to, specified by their app IDs | `order-processor`, `checkout`
| **metadata** | - | **Information about the component registration** |
| metadata.name | Y | The name of the component | `prod-statestore`
| metadata.namespace | N | The namespace for the component for hosting environments with namespaces | `myapp-namespace`
| **spec** | - | **Detailed information on the component resource**
| spec.type | Y | The type of the component | `state.redis`
| spec.version | Y | The version of the component | `v1`
| spec.initTimeout | N | The timeout duration for the initialization of the component. Default is 5s | `5m`, `1h`, `20s`
| spec.ignoreErrors | N | Tells the Dapr sidecar to continue initialization if the component fails to load. Default is false | `false`
| **spec.metadata** | - | **A key/value pair of component specific configuration. See your component definition for fields**|
| spec.metadata.name | Y | The name of the component-specific property and its value | `- name: secretsFile` <br> `value: secrets.json`
### Templated metadata values
Metadata values can contain template tags that are resolved on Dapr sidecar startup. The table below shows the current templating tags that can be used in components.
| Tag | Details | Example use case |
|-------------|--------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| {uuid} | Randomly generated UUIDv4 | When you need a unique identifier in self-hosted mode; for example, multiple application instances consuming a [shared MQTT subscription]({{< ref "setup-mqtt3.md" >}}) |
| {podName} | Name of the pod containing the Dapr sidecar | Use to have a persisted behavior, where the ConsumerID does not change on restart when using StatefulSets in Kubernetes |
| {namespace} | Namespace where the Dapr sidecar resides combined with its appId | Using a shared `clientId` when multiple application instances consume a Kafka topic in Kubernetes |
| {appID} | The configured `appID` of the resource containing the Dapr sidecar | Having a shared `clientId` when multiple application instances consumer a Kafka topic in self-hosted mode |
Below is an example of using the `{uuid}` tag in an MQTT pubsub component. Note that multiple template tags can be used in a single metadata value.
```yaml
apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
name: messagebus
spec:
type: pubsub.mqtt3
version: v1
metadata:
- name: consumerID
value: "{uuid}"
- name: url
value: "tcp://admin:public@localhost:1883"
- name: qos
value: 1
- name: retain
value: "false"
- name: cleanSession
value: "false"
```
## Related links
- [Components concept]({{< ref components-concept.md >}})
- [Reference secrets in component definitions]({{< ref component-secrets.md >}})
- [Supported state stores]({{< ref supported-state-stores >}})
- [Supported pub/sub brokers]({{< ref supported-pubsub >}})
- [Supported secret stores]({{< ref supported-secret-stores >}})
- [Supported bindings]({{< ref supported-bindings >}})
- [Set component scopes]({{< ref component-scopes.md >}})