Usage

Process

Figure 1 Device policy usage process

Procedure

The following example describes how to set topic policies and bind policy targets on the IoTDA console for MQTT device.

1. Go to the policy page. Access the IoTDA service page and click Access Console. Click the target instance card. In the navigation pane, choose Devices > Policies.
   Figure 2 Device policy - Access page
   
2. Create a policy. Click Create Policy, set policy parameters based on service requirements, and click Generate. The following figure shows the example parameter values.
   Figure 3 Device policy - Creating a policy
   

   Table 1 Parameter description

   Parameter Description
   Resource Space	Select a resource space from the drop-down list box or create one.
   Policy Name	Customize a value, for example, PolicyTest. The value is a string of no more than 128 characters. Only letters, digits, underscores (_), and hyphens (-) are allowed.
   Resource	For MQTT topic publishing and subscription, topic: must be used as the parameter prefix. For example, to forbid the subscription to /test/v1, set this parameter to topic:/test/v1.
   Operation	Options: Publish and Subscribe, meaning the topic publishing and subscription requests of MQTT devices.
   Permission	Options: Allowed and Denied, meaning whether the permission to publish or subscribe to messages of a topic is assigned.

3. Bind the policy target. A policy can be bound to resource spaces, products, or devices. The bound devices are allowed or disallowed to publish or subscribe to messages through a specific topic accordingly.
   Figure 4 Device policy - Binding a device
   

   Table 2 Parameter description

   Parameter Description
   Target Type	You can set resource spaces, products, or devices as the target type. The three types can coexist. For example, product A and device C (under product B) can be bound to the same policy. Resource space: used for domain-based management of multiple service applications. After a resource space is bound to a policy, all devices in this resource space adopt the policy. You can also select multiple resource spaces for binding. Product: Generally, a product has multiple devices. After a product is bound to a policy, all devices of this product adopt the policy. Compared with the resource space, the binding scope is smaller. You can select products in different resource spaces for binding. Device: minimum unit for the target bound to a policy. You can select devices from different resource spaces and products for binding.
   Target	After you select a policy target type, available targets are displayed in the Target area. Select targets as required.