What are the differences between the Message Notification Service and the query Method?

You can monitor the status of the cloud recording service either through the query method or by the Message Notification Service, to take action when required. Both options have pros and cons.

You can periodically call the query method to monitor the status of a cloud recording. See Query the recording status.

• Pros: Reliable, as the status is queried proactively.
• Cons:
  • Provides limited status information.
  • Requires an active query. You cannot query too often because of the Queries Per Second (QPS) limit, and thus it is not as real-time as the Message Notification Service.

If the reliability of the status of a cloud recording is a high priority, Agora strongly recommends using the query method.

You can use the Message Notification Service as a complementary option to monitor the recording service status. You need to configure an HTTP/HTTPS server to receive event notifications. For details, see Agora Cloud Recording RESTful API Callback Service.

• Pros: Real-time
• Cons:
  • The server passively receives messages, and the messages may get lost.
  • The confirmation message of the message delivery may get lost, causing the message to be resent. In such a case, you need to deduplicate the notifications.
  • The messages may not arrive in the correct order.

Agora recommends that core apps should not rely on the Message Notification Service. If your apps already rely heavily on the Message Notification Service, Agora recommends that you contact  support@agora.io to enable the redundant message notification function, which doubles the received notifications and reduces the probability of message loss. Redundant message notification still cannot guarantee a 100% arrival rate.