How-To: Share state between applications

Choose different strategies for sharing state between different applications

介绍

Dapr 为开发者提供了不同的方式来共享应用程序之间的状态。

在共享状态时，不同的体系结构可能有不同的需求。 例如，在一个场景中，您可能想要封装某个应用程序中的所有状态，并让 Dapr 管理您的访问权限。 在不同的场景中，您可能需要两个在相同状态下工作的应用程序能够获得和保存相同的键值(keys)。

要启用状态共享， Dapr 支持以下键前缀策略:

• Appid - 这是默认策略。 the appid prefix allows state to be managed only by the app with the specified appid. All state keys will be prefixed with the appid, and are scoped for the application.

• name - This setting uses the name of the state store component as the prefix. Multiple applications can share the same state for a given state store.

• none - This setting uses no prefixing. Multiple applications share state across different state stores.

Specifying a state prefix strategy

To specify a prefix strategy, add a metadata key named keyPrefix on a state component:

apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
  name: statestore
  namespace: production
spec:
  type: state.redis
  version: v1
  metadata:
  - name: keyPrefix
    value: <key-prefix-strategy>

Examples

The following examples will show you how state retrieval looks like with each of the supported prefix strategies:

appid (default)

A Dapr application with app id myApp is saving state into a state store named redis:

curl -X POST http://localhost:3500/v1.0/state/redis \
  -H "Content-Type: application/json"
  -d '[
        {
          "key": "darth",
          "value": "nihilus"
        }
      ]'

The key will be saved as myApp||darth.

name

A Dapr application with app id myApp is saving state into a state store named redis:

curl -X POST http://localhost:3500/v1.0/state/redis \
  -H "Content-Type: application/json"
  -d '[
        {
          "key": "darth",
          "value": "nihilus"
        }
      ]'

The key will be saved as redis||darth.

none

A Dapr application with app id myApp is saving state into a state store named redis:

curl -X POST http://localhost:3500/v1.0/state/redis \
  -H "Content-Type: application/json"
  -d '[
        {
          "key": "darth",
          "value": "nihilus"
        }
      ]'

The key will be saved as darth.

Last modified January 1, 0001