Scalable self-healing architecture for client-server operations in transient connectivity conditions

• US 10,609,155 B2
• Filed: 02/20/2015
• Issued: 03/31/2020
• Est. Priority Date: 02/20/2015
• 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, White Eagle, Brian L.
• Primary Examiner(s): Recek, Jason D
• Assistant Examiner(s): Pant, Ranjan
• Application Number:
  US14/627,182
• Publication Number:
  US 20160248836A1
• Time in Patent Office: 1,866 Days
• CPC Class Codes: H04L 67/1027 Persistence of sessions during load balancing
• CPC Class Codes: H04L 67/146 Markers for unambiguous identification of a particular session, e.g. session cookie or URL-encoding

Abstract

A method, system, and computer program product for scalable and self-healing architecture for client-server operations in transient connectivity conditions are provided in the illustrative embodiments. An application in a second system receives a request from a first system, the request requesting data from a type of service. A first response responds to the request. The request is queued in a service queue corresponding to the type of the service, to make the request available to a third system that provides the type of the service. A notification is received that a second response from the third data processing system has been posted into a session specific queue, the second response being responsive to the request. In response to another request received from the first system, a third response is sent to the first system, the third response including the data from the second response from the session specific queue.

Claims

1. A method for managing data requests in transient network conditions, the method comprising:

receiving a first client request from a client data processing system, over a data network, at an agent application executing using a processor and a memory in an agent data processing system, the first client request requesting data from a type of service;

responding to the first client request with a first agent response, the first agent response comprising an acknowledgement message to acknowledge receiving the first client request at the agent application;

identifying the type of service requested by the first client request based upon an identifier associated with the first client request;

determining, by the agent application, responsive to the first client request, whether a service queue corresponding to the identified type of service exists for the first client request;

creating, by the agent application, responsive to the agent application determining that the service queue does not exist, the service queue corresponding to the identified type of service for the first client request by consulting a lookup service specified as part of configuring a backend service, the lookup service mapping the identified type of service to the service queue;

queuing the first client request in the service queue corresponding to the identified type of the service, to make the first client request available to a server data processing system that provides the type of the service;

detecting a loss of connectivity between the client data processing system and the agent data processing system;

purging, responsive to the loss of connectivity between the client data processing system and the agent data processing system exceeding a timeout period, the service queue corresponding to the first client request;

receiving a notification that a server response from the server data processing system has been posted into a session specific queue, the session specific queue being a server-created queue responsive to the server data processing system detecting that the service queue has been purged, the server response being responsive to the first client request;

detecting a restoration of connectivity between the client data processing system and the agent data processing system; and

sending, in response to a second client request received from the client data processing system, an agent response, the agent response including the data from the server response posted in the session specific queue, the second client request comprising an HTTP Get request, the agent response responsive to the first client request such that the client data processing system does not have to retransmit the first client request responsive to the restoration of connectivity.

2. The method of claim 1, further comprising:

detecting that a fourth response has been posted in the session specific queue;

determining that the fourth response remained in the session specific queue for a message timeout period; and

purging the fourth response from the session specific queue.

3. The method of claim 1, further comprising:

identifying that the session specific queue exists for a session with the client data processing system;

determining that the agent application has not received a communication from the client data processing system for a queue timeout period; and

deleting the session specific queue.

4. The method of claim 1, further comprising:

removing the server response from the session specific queue.

5. The method of claim 1, further comprising:

receiving the second client request from the client data processing system, wherein the second client request opens a channel over which the agent response can be transmitted to the client data processing system.

6. The method of claim 5, further comprising:

determining whether the session specific queue exists;

creating, responsive to the session specific queue not existing, the session specific queue consequent to receiving the second client request; and

subscribing to the session specific queue.

7. The method of claim 5, further comprising:

determining whether the session specific queue exists;

subscribing, responsive to the session specific queue existing, to the session specific queue.

8. The method of claim 1, further comprising:

causing, by the responding, the client data processing system to complete a request-response pair using the first client request and the first agent response such that the client data processing system does not have to retransmit the first client request even though the client data processing system has not received the data in the first agent response.

9. The method of claim 1, further comprising:

causing the responding to occur within a first time period from the first client request, wherein the first time period is shorter than a second time period from the first client request, the second time period being needed to provide the data requested in the first client request, and wherein the data network is available during the first time period but the data network becomes unavailable during the second time period.

10. The method of claim 1, further comprising:

sending, responsive to a handshake message from the client data processing system, from a second application to the client data processing system, a session identifier to establish a session with the client data processing system;

wherein the first client request comprises a Hypertext Transfer Protocol (HTTP) request in the session and uses the session identifier,

wherein the agent response comprises a response to the HTTP Get request.

11. The method of claim 1, wherein a second application receives the second client request, and wherein the agent application and the second application are instances of an agent application operating in a load sharing configuration.

12. The method of claim 1, wherein the lookup service performs the queuing of the first client request in the service queue corresponding to the backend service.

13. A computer usable program product comprising a computer readable storage device including computer usable code for managing data requests in transient network conditions, the computer usable code comprising:

computer usable code for receiving a first client request from a client data processing system, over a data network, at an agent application executing using a processor and a memory in an agent data processing system, the first client request requesting data from a type of service;

computer usable code for responding to the first client request with a first agent response, the first agent response comprising an acknowledgement message to acknowledge receiving the first client request at the agent application;

computer usable code for identifying the type of service requested by the first client request based upon an identifier associated with the first client request;

computer usable code for determining, by the agent application, responsive to the first client request, whether a service queue corresponding to the identified type of service exists for the first client request;

computer usable code for creating, by the agent application, responsive to the agent application determining that the service queue does not exist, the service queue corresponding to the identified type of service for the first client request by consulting a lookup service specified as part of configuring a backend service, the lookup service mapping the identified type of service to the service queue;

computer usable code for queuing the first client request in the service queue corresponding to the identified type of the service, to make the first client request available to a server data processing system that provides the type of the service;

computer usable code for detecting a loss of connectivity between the client data processing system and the agent data processing system;

computer usable code for purging, responsive to the loss of connectivity between the client data processing system and the agent data processing system exceeding a timeout period, the service queue corresponding to the first client request;

computer usable code for receiving a notification that a server response from the server data processing system has been posted into a session specific queue, the session specific queue being a server-created queue responsive to the server data processing system detecting that the service queue has been purged, the server response being responsive to the first client request;

computer usable code for detecting a restoration of connectivity between the client data processing system and the agent data processing system; and

computer usable code for sending, in response to a second client request received from the client data processing system, an agent response, the agent response including the data from the server response posted in the session specific queue, the second client request comprising an HTTP Get request, the agent response responsive to the first client request such that the client data processing system does not have to retransmit the first client request responsive to the restoration of connectivity.

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

computer usable code for detecting that a fourth response has been posted in the session specific queue;

computer usable code for determining that the fourth response remained in the session specific queue for a message timeout period; and

computer usable code for purging the fourth response from the session specific queue.

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

computer usable code for identifying that the session specific queue exists for a session with the client data processing system;

computer usable code for determining that the agent application has not received a communication from the client data processing system for a queue timeout period; and

computer usable code for deleting the session specific queue.

16. The computer usable program product of claim 13, 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.

17. The computer usable program product of claim 13, 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.

18. A data processing system for managing data requests in transient network conditions, 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 receiving a first client request from a client data processing system, over a data network, at an agent application executing using a processor and a memory in an agent data processing system, the first client request requesting data from a type of service;

computer usable code for responding to the first client request with a first agent response, the first agent response comprising an acknowledgement message to acknowledge receiving the first client request at the agent application;

computer usable code for identifying the type of service requested by the first client request based upon an identifier associated with the first client request;

computer usable code for determining, by the agent application, responsive to the first client request, whether a service queue corresponding to the identified type of service exists for the first client request;

computer usable code for creating, by the agent application, responsive to the agent application determining that the service queue does not exist, the service queue corresponding to the identified type of service for the first client request by consulting a lookup service specified as part of configuring a backend service, the lookup service mapping the identified type of service to the service queue;

computer usable code for queuing the first client request in the service queue corresponding to the identified type of the service, to make the first client request available to a server data processing system that provides the type of the service;

computer usable code for detecting a loss of connectivity between the client data processing system and the agent data processing system;

computer usable code for purging, responsive to the loss of connectivity between the client data processing system and the agent data processing system exceeding a timeout period, the service queue corresponding to the first client request;

computer usable code for receiving a notification that a server response from the server data processing system has been posted into a session specific queue, the session specific queue being a server-created queue responsive to the server data processing system detecting that the service queue has been purged, the server response being responsive to the first client request;

computer usable code for detecting a restoration of connectivity between the client data

processing system and the agent data processing system; and

computer usable code for sending, in response to a second client request received from the client data processing system, an agent response, the agent response including the data from the server response posted in the session specific queue, the second client request comprising an HTTP Get request, the agent response responsive to the first client request such that the client data processing system does not have to retransmit the first client request responsive to the restoration of connectivity.