Resource tracking

• US 8,335,762 B2
• Filed: 10/06/2008
• Issued: 12/18/2012
• Est. Priority Date: 10/06/2008
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Gbadegesin, Abolade, Mody, Viraj B., Steere, David C., Zintel, William Michael, Copeland, Bruce W., Adya, Atul, Kleinpeter, Thomas W.
• Primary Examiner(s): BROWN, SHEREE N
• Application Number:
  US12/245,972
• Publication Number:
  US 20100088300A1
• Time in Patent Office: 1,534 Days
• Field of Search: 707/3, 707/628
• US Class Current: 707/628
• CPC Class Codes: G06F 16/24568 Data stream processing; Continuous queries
• CPC Class Codes: H04L 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes

Abstract

Clients may subscribe to resources for the purpose of receiving notifications of changes in the resource (e.g., a file is added to a shared folder). Storing subscriptions within persistent storage provides data security in the event of a service failure, at the cost of high latency in accessing subscription data. An efficient method for tracking a resource is provided herein. A subscription service creates subscriptions and monitors resources for a client. Upon a subscribed resource change, a notification service stores a notification of the change into a queue associated with the client. Efficient resource tracking is achieved because notification and subscription data is stored in low latency soft memory. The notification service is configured to detect a failure in the notification service and/or subscription service. In the event a service fails, the client provides a recovery mechanism by resubscribing to resources the client is interested in.

Claims

1. A system for distributing information regarding a resource, comprising:

a notification service configured to;

maintain a queue within volatile memory on behalf of a client, comprising;

storing one or more notifications within the queue, a notification corresponding to a change of a resource that is monitored by a subscription service on behalf of the client; and

providing the client with read access to the queue;

monitor for a subscription state loss associated with the subscription service, comprising;

responsive to identifying the subscription state loss associated with the subscription service, storing a subscription service failure notification within the queue; and

monitor for a queue state loss associated with the notification service, comprising;

responsive to identifying the queue state loss associated with the notification service, creating a new queue to replace the queue and storing a notification service failure notification within the new queue, at least some of the notification service implemented at least in part via a processing unit.

2. The system of claim 1, the notification service configured to:

receive a request from the client to access the queue, the request comprising a notification service identifier that identifies the notification service and a queue identifier that identifies the queue; and

responsive to the notification service identifier matching a current notification service identifier that identifies a current instance of the notification service, provide the client with access to the queue identified by the queue identifier.

3. The system of claim 1, the notification service configured to:

receive a request from the client to access the queue, the request comprising a notification service identifier that identifies the notification service and a queue identifier that identifies the queue;

identify the queue state loss based upon the notification service identifier not matching a current notification service identifier that identifies a current instance of the notification service; and

responsive to identifying the queue state loss;

create the new queue comprising a new queue identifier; and

store the notification service failure notification within the new queue, the notification service failure notification comprising at least one of;

a message that the notification service failed;

an instruction for the client to resubscribe, with the subscription service, to the resource;

the new queue identifier identifying the new queue maintained on behalf of the client by the notification service;

or

the current notification service identifier that identifies the current instance of the notification service.

4. The system of claim 1, the subscription service failure notification comprising at least one of a message that the subscription service failed or an instruction for the client to resubscribe to the resource with the subscription service.

5. The system of claim 1, the notification service configured to:

receive a subscription update, corresponding to a change in the resource subscribed to by the client through the subscription service, from the subscription service, the subscription update comprising a queue identifier that identifies the queue maintained by the notification service on behalf of the client; and

store a notification of the subscription update within the queue identified by the queue identifier.

6. The system of claim 1, the notification service configured to:

maintain a plurality of queues associated with one or more clients; and

store a notification of a subscription update, corresponding to a change in a target resource subscribed to by a target client through the subscription service, within a target queue maintained on behalf of the target client based upon the subscription update comprising a target queue identifier that identifies the target queue.

7. The system of claim 1, the notification service configured to receive a request from the client, the request comprising at least one of:

a create queue instruction;

an instruction to extract one or more notifications from the queue;

a notification service identifier corresponding to a current instance or a prior instance of the notification service;

or

a queue identifier corresponding to the queue.

8. The system of claim 1, comprising:

the subscription service configured to;

receive a subscription request from the client to monitor the resource for changes, the subscription request comprising a resource identifier that identifies the resource and a queue identifier that identifies the queue maintained by the notification service on behalf of the client; and

create a subscription to the resource.

9. The system of claim 8, the subscription service configured to:

store, at the client, subscription information regarding the subscription.

10. The system of claim 8, the subscription service configured to:

store the subscription within volatile memory.

11. The system of claim 8, the subscription service configured to:

responsive to detecting a change to the resource, send a subscription update to the notification service, the subscription update comprising the queue identifier that identifies the queue within which the notification service is to store a notification of the subscription update.

12. The system of claim 8, the subscription service configured to:

associate a time to live value with the resource; and

remove the subscription to the resource responsive to the time to live value falling below a threshold.

13. The system of claim 8, the subscription comprising at least one of:

the queue identifier for the queue;

or

an address associated with the resource.

14. The system of claim 8, the resource comprising social network data.

15. A method for distributing information regarding a resource, comprising:

maintaining a queue within volatile memory on behalf of a client, the maintaining comprising;

storing one or more notifications within the queue, a notification corresponding to a change of a resource that is monitored by a subscription service on behalf of the client; and

providing the client with read access to the queue;

monitoring for a subscription state loss associated with the subscription service, the monitoring for a subscription state loss comprising;

responsive to identifying the subscription state loss associated with the subscription service, storing a subscription service failure notification within the queue; and

monitoring for a queue state loss associated with a notification service, the monitoring for a queue state loss comprising;

responsive to identifying the queue state loss associated with the notification service, creating a new queue to replace the queue and storing a notification service failure notification within the new queue, at least some of at least one of the maintaining, the monitoring for a subscription state loss, or the monitoring for a queue state loss implemented at least in part via a processing unit.

16. The method of claim 15, comprising:

receiving a request from the client to access the queue, the request comprising a notification service identifier that identifies the notification service and a queue identifier that identifies the queue; and

responsive to the notification service identifier matching a current notification service identifier that identifies a current instance of the notification service, providing the client with access to the queue identified by the queue identifier.

17. The method of claim 15, comprising:

receiving a request from the client to access the queue, the request comprising a notification service identifier that identifies the notification service and a queue identifier that identifies the queue;

identifying the queue state loss based upon the notification service identifier not matching a current notification service identifier that identifies a current instance of the notification service; and

responsive to identifying the queue state loss;

creating the new queue comprising a new queue identifier; and

storing the notification service failure notification within the new queue, the notification service failure notification comprising at least one of;

a message that the notification service failed;

an instruction for the client to resubscribe, with the subscription service, to the resource;

the new queue identifier identifying the new queue maintained on behalf of the client by the notification service;

or

the current notification service identifier that identifies the current instance of the notification service.

18. The method of claim 15, comprising:

receiving a subscription update, corresponding to a change in the resource subscribed to by the client through the subscription service, from the subscription service, the subscription update comprising a queue identifier that identifies the queue maintained by the notification service on behalf of the client; and

storing a notification of the subscription update within the queue.

19. A computer-readable medium comprising processor-executable instructions that when executed perform a method for distributing information regarding a resource, comprising:

maintaining a queue within volatile memory on behalf of a client, the maintaining comprising;

storing one or more notifications within the queue, a notification corresponding to a change of a resource that is monitored by a subscription service on behalf of the client; and

providing the client with read access to the queue;

monitoring for a subscription state loss associated with the subscription service, the monitoring for a subscription state loss comprising;

responsive to identifying the subscription state loss associated with the subscription service, storing a subscription service failure notification within the queue; and

monitoring for a queue state loss associated with a notification service, the monitoring for a queue state loss comprising;

responsive to identifying the queue state loss associated with the notification service, creating a new queue to replace the queue and storing a notification service failure notification within the new queue.

20. The computer-readable medium of claim 19, comprising:

receiving a request from the client to access the queue, the request comprising a notification service identifier that identifies the notification service and a queue identifier that identifies the queue;

identifying the queue state loss based upon the notification service identifier not matching a current notification service identifier that identifies a current instance of the notification service; and

responsive to identifying the queue state loss;

creating the new queue comprising a new queue identifier; and

storing the notification service failure notification within the new queue, the notification service failure notification comprising at least one of;

a message that the notification service failed;

an instruction for the client to resubscribe, with the subscription service, to the resource;

the new queue identifier identifying the new queue maintained on behalf of the client by the notification service;

or

the current notification service identifier that identifies the current instance of the notification service.