Client-side fault tolerance in a publish-subscribe system

• US 10,439,916 B2
• Filed: 06/08/2017
• Issued: 10/08/2019
• Est. Priority Date: 03/05/2015
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Agarwal, Kanak B., Bohrer, Patrick J., Gheith, Ahmed, Kistler, Michael D., Rajamony, Ramakrishnan
• Primary Examiner(s): Jean, Frantz B
• Application Number:
  US15/617,379
• Publication Number:
  US 20170272346A1
• Time in Patent Office: 852 Days
• Field of Search: 709203, 709206
• CPC Class Codes: H04L 43/10 Active monitoring, e.g. heartbeat, ping or trace-route
• CPC Class Codes: H04L 67/01 Protocols
• CPC Class Codes: H04L 67/145 avoiding end of session, e.g. keep-alive, heartbeats, resumption message or wake-up for inactive or interrupted session
• CPC Class Codes: H04L 67/55 Push-based network services

Abstract

To provide client-side fault-tolerance in a publish-subscribe system, a message is received on a channel from a server. At a function executing using a processor and a memory, a determination is made whether the message contains a heartbeat data. When the message contains the heartbeat data, a determination is made whether a content signature contained in the message matches a last known content signature saved from a previous message. When the content signature contained in the message does not match the last known content signature saved from a previous message, a refresh message is sent to the channel.

Claims

1. A method for client-side fault-tolerance in a publish-subscribe system, the method comprising:

saving a last known content signature from a previous message when the previous message is received on a channel at a server;

receiving, on the channel, a message from the server;

determining, at a function executing using a processor and a memory, whether the message contains a heartbeat data, wherein the message includes a content signature;

determining, responsive to the message containing the heartbeat data, whether a client is in sync with the server for a content published by the server by determining whether the content signature contained in the message matches the last known content signature; and

sending, responsive to the content signature contained in the message not matching the last known content signature, a refresh message to the channel, the refresh message causing a response to an original request to be re-received on the channel.

2. The method of claim 1, further comprising:

receiving an other message after the message;

determining that the other message carries content and a corresponding content signature; and

saving the content signature of the other message as the last known content signature.

3. The method of claim 1, wherein the content signature contained in the message comprises a content signature used by the server in a last message that carried content, wherein the content is responsive to a request, and wherein the heartbeat data is not responsive to the request.

4. The method of claim 1, further comprising:

activating a timeout timer upon receiving the previous message;

determining that the message has been received on the channel prior to the timeout timer expiring; and

resetting and reactivating the timeout timer upon receiving the message.

5. The method of claim 1, further comprising:

activating a timeout timer upon receiving an other message; and

re-subscribing to the channel, responsive to the timeout timer expiring prior to receiving a next message subsequent to the other message.

6. The method of claim 1, further comprising:

clearing, responsive to sending the refresh message, the last known content signature from the previous message.

7. The method of claim 1, further comprising:

receiving, responsive to the refresh message, a response message; and

setting the last known content signature with a content signature contained in the response message.

8. The method of claim 1, further comprising:

activating a timeout timer upon receiving the response message;

receiving, prior to the timeout timer expiring, a next message subsequent to the response message;

determining that the next message carries a second heartbeat data;

determining that a second content signature contained in the next message matches the last known content signature saved from the response message; and

resetting and reactivating the timeout timer upon receiving the next message.

9. The method of claim 8, further comprising:

monitoring the channel for a content update from the server.

10. A computer usable program product comprising a computer readable storage device including computer usable code for client-side fault-tolerance in a publish-subscribe system, the computer usable code comprising:

computer usable code for saving a last known content signature from a previous message when the previous message is received on a channel at a server;

computer usable code for receiving, on the channel, a message from the server;

computer usable code for determining, at a function executing using a processor and a memory, whether the message contains a heartbeat data, wherein the message includes a content signature;

computer usable code for determining, responsive to the message containing the heartbeat data, whether a client is in sync with the server for a content published by the server by determining whether the content signature contained in the message matches the last known content signature; and

computer usable code for sending, responsive to the content signature contained in the message not matching the last known content signature, a refresh message to the channel, the refresh message causing a response to an original request to be re-received on the channel.

11. The computer usable program product of claim 10, further comprising:

computer usable code for receiving an other message after the message;

computer usable code for determining that the other message carries content and a corresponding content signature; and

computer usable code for saving the content signature of the other message as the last known content signature.

12. The computer usable program product of claim 10, wherein the content signature contained in the message comprises a content signature used by the server in a last message that carried content, wherein the content is responsive to a request, and wherein the heartbeat data is not responsive to the request.

13. The computer usable program product of claim 10, further comprising:

computer usable code for activating a timeout timer upon receiving the previous message;

computer usable code for determining that the message has been received on the channel prior to the timeout timer expiring; and

computer usable code for resetting and reactivating the timeout timer upon receiving the message.

14. The computer usable program product of claim 10, further comprising:

computer usable code for activating a timeout timer upon receiving an other message; and

computer usable code for re-subscribing to the channel, responsive to the timeout timer expiring prior to receiving a next message subsequent to the other message.

15. The computer usable program product of claim 10, further comprising:

computer usable code for clearing, responsive to sending the refresh message, the last known content signature from the previous message.

16. The computer usable program product of claim 10, further comprising:

computer usable code for receiving, responsive to the refresh message, a response message; and

computer usable code for setting the last known content signature with a content signature contained in the response message.

17. The computer usable program product of claim 10, further comprising:

computer usable code for activating a timeout timer upon receiving the response message;

computer usable code for receiving, prior to the timeout timer expiring, a next message subsequent to the response message;

computer usable code for determining that the next message carries a second heartbeat data;

determining that a second content signature contained in the next message matches the last known content signature saved from the response message; and

computer usable code for resetting and reactivating the timeout timer upon receiving the next message.

18. The computer usable program product of claim 10, wherein the computer usable code is stored in a computer readable storage device in a data processing system, and wherein the computer usable code is transferred over a network from a remote data processing system.

19. The computer usable program product of claim 10, wherein the computer usable code is stored in a computer readable storage device in a server data processing system, and wherein the computer usable code is downloaded over a network to a remote data processing system for use in a computer readable storage device associated with the remote data processing system.

20. A data processing system for client-side fault-tolerance in a publish-subscribe system, the data processing system comprising:

a storage device, wherein the storage device stores computer usable program code; and

a processor, wherein the processor executes the computer usable program code, and wherein the computer usable program code comprises;

computer usable code for saving a last known content signature from a previous message when the previous message is received on a channel at a server;

computer usable code for receiving, on the channel, a message from the server;

computer usable code for determining, at a function executing using a processor and a memory, whether the message contains a heartbeat data, wherein the message includes a content signature;

computer usable code for determining, responsive to the message containing the heartbeat data, whether a client is in sync with the server for a content published by the server by determining whether the content signature contained in the message matches the last known content signature; and

computer usable code for sending, responsive to the content signature contained in the message not matching the last known content signature, a refresh message to the channel, the refresh message causing a response to an original request to be re-received on the channel.