Changing an event identifier of a transient event in an event notification system

• US 8,984,119 B2
• Filed: 11/05/2010
• Issued: 03/17/2015
• Est. Priority Date: 11/05/2010
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Jennings, Cheryl L., Mishra, Rajeev, Nayar, Trishali, Russell, Lance W.
• Primary Examiner(s): Vu, Viet
• Assistant Examiner(s): BELCHER, HERMAN A
• Application Number:
  US12/940,137
• Publication Number:
  US 20120117223A1
• Time in Patent Office: 1,593 Days
• Field of Search: 709/224
• US Class Current: 709/224
• CPC Class Codes: G06F 9/542 Event management; Broadcasting; Multicasting; Notifications

Abstract

An event notification system for distributed processing systems provides for replacement of event identifiers associated with transient objects, such as processes within the processing system. An event management interface receives a notification from an event producer that an identifier of an event produced by the event producer is no longer valid. The event management interface blocks event notification for the event and dissociates an event registration entry associated with the event from the event identifier. A new event identifier is received from the event producer by the event management interface, which associates the registration entry with the new event identifier. Event notification for the event is then resumed.

Claims

1. A method for operating an event notification system within a cluster of nodes of a computer system, the method comprising:

from the event notification system, transmitting event notifications providing indications of an event occurring within the computer system, to one or more event consumers in response to event notifications received an event producer of the event and according to an event registration entry within the event notification system;

first receiving, at an event management interface and from the event producer of the event, a notification that an event identifier associated with the event in the event registration entry is no longer valid;

responsive to receiving the notification that the event identifier is no longer valid at the event management interface, blocking event notification for the event at the event management interface, whereby the transmitting of the event notifications to the event consumers is suspended;

further responsive to receiving the notification that the event identifier is no longer valid at the event management interface, dissociating the event identifier from the event registration entry, while maintaining the event registration entry;

second receiving, from the event producer, a new event identifier associated with the event;

responsive to second receiving the new event identifier, associating the registration entry with the new event identifier; and

responsive to associating the registration entry with the new event identifier, at the event management interface, resuming event notification for the event, whereby the transmitting of the event notifications to the event consumers is resumed.

2. The method of claim 1, wherein the event management interface, in response to the first receiving, performs the blocking and dissociating and returns a cookie associated with the event registration entry to the event producer, wherein the event producer further provides the cookie with the new event identifier, whereby the second receiving receives the cookie, and wherein the method further locates the registration entry using the cookie and performs the associating in conformity with a result of the locating.

3. The method of claim 1, wherein the event management interface is an interface of a file system that implements event notification in the computer system, wherein the event registration entry is a data structure providing a specifier of a file in the file system representing the event, and wherein the maintaining comprises retaining the file in the file system and the specifier in the data structure while the file is not associated with the event identifier.

4. The method of claim 3, wherein the dissociating writes an indication to the file that the event identifier has been dissociated, whereby an event consumer associated with the file is notified that the event identifier has been dissociated.

5. The method of claim 4, wherein the dissociating further writes an indication of a particular action taken by the producer that caused removal of the event identifier.

6. The method of claim 1, wherein the event is associated with a process, wherein the process is terminated causing the event identifier to become no longer valid, wherein a replacement process is spawned subsequent to termination of the process, and wherein the second receiving is performed responsive to spawning of the replacement process.

7. The method of claim 1, wherein the process has a first process identifier wherein the replacement process has a second process identifier, and wherein the event identifier is the first process identifier and the new event identifier is the second process identifier.

8. A computer system comprising a processing cluster including a plurality of physical or virtual processing nodes, the computer system comprising at least one processor for executing program instructions and at least one memory coupled to the processor for executing the program instructions, wherein the program instructions are program instructions for providing event notification within the computer system and implementing an event management interface, the program instructions comprising program instructions for:

from an event notification system, transmitting event notifications providing indications of an event occurring within the computer system, to one or more event consumers in response to event notifications received an event producer of the event and according to an event registration entry within the event notification system;

first receiving, at the event management interface and from the event producer of the event, a notification that an event identifier associated with the event in the event registration entry is no longer valid;

responsive to receiving the notification that the event identifier is no longer valid at the event management interface, blocking event notification for the event at the event management interface, whereby the transmitting of the event notifications to the event consumers is suspended;

further responsive to receiving the notification that the event identifier is no longer valid at the event management interface, dissociating the event identifier from the event registration entry, while maintaining the event registration entry;

second receiving, from the event producer, a new event identifier associated with the event;

responsive to second receiving the new event identifier, associating the registration entry with the new event identifier; and

responsive to associating the registration entry with the new event identifier, at the event management interface, resuming event notification for the event, whereby the transmitting of the event notifications to the event consumers is resumed.

9. The computer system of claim 8, wherein the program instructions for implementing the event management interface, in response to the first receiving, perform the blocking and dissociating and return a cookie associated with the event registration entry to the event producer, wherein the event producer further provides the cookie with the new event identifier, whereby the program instructions for second receiving receive the cookie, and wherein the program instructions further comprise program instructions for locating the registration entry using the cookie and performing the associating in conformity with a result of the locating.

10. The computer system of claim 8, wherein the event management interface is an interface of a file system that implements event notification in the computer system, wherein the event registration entry is a data structure providing a specifier of a file in the file system representing the event, and wherein the program instructions for maintaining retain the file in the file system and the specifier in the data structure while the file is not associated with the event identifier.

11. The computer system of claim 10, wherein the program instructions for dissociating write an indication to the file that the event identifier has been dissociated, whereby an event consumer associated with the file is notified that the event identifier has been dissociated.

12. The computer system of claim 11, wherein the program instructions for dissociating further write an indication of a particular action taken by the producer that caused removal of the event identifier.

13. The computer system of claim 8, wherein the event is associated with a process, wherein the process is terminated causing the event identifier to become no longer valid, wherein a replacement process is spawned subsequent to termination of the process, and wherein the program instructions for second receiving receive the notification in response to spawning of the replacement process.

14. The computer system of claim 8, wherein the process has a first process identifier wherein the replacement process has a second process identifier, and wherein the event identifier is the first process identifier and the new event identifier is the second process identifier.

15. A computer program product comprising a computer-readable storage device storing program instructions for execution within a computer system, the computer system comprising a processing cluster including a plurality of physical or virtual processing nodes, wherein the program instructions are program instructions for providing event notification within the computer system and implementing an event management interface, the program instructions comprising program instructions for:

from the event notification system, transmitting event notifications providing indications of an event occurring within the computer system, to one or more event consumers in response to event notifications received an event producer of the event and according to an event registration entry within the event notification system;

first receiving, at the event management interface and from the event producer of the event, a notification that an event identifier associated with the event in the event registration entry is no longer valid;

responsive to receiving the notification that the event identifier is no longer valid at the event management interface, blocking event notification for the event at the event management interface, whereby the transmitting of the event notifications to the event consumers is suspended;

further responsive to receiving the notification that the event identifier is no longer valid at the event management interface, dissociating the event identifier from the event registration entry, while maintaining the event registration entry;

second receiving, from the event producer, a new event identifier associated with the event;

responsive to second receiving the new event identifier, associating the registration entry with the new event identifier; and

responsive to associating the registration entry with the new event identifier, at the event management interface, resuming event notification for the event, whereby the transmitting of the event notifications to the event consumers is resumed.

16. The computer program product of claim 15, wherein the program instructions for implementing the event management interface, in response to the first receiving, perform the blocking and dissociating and return a cookie associated with the event registration entry to the event producer, wherein the event producer further provides the cookie with the new event identifier, whereby the program instructions for second receiving receive the cookie, and wherein the program instructions further comprise program instructions for locating the registration entry using the cookie and performing the associating in conformity with a result of the locating.

17. The computer program product of claim 15, wherein the event management interface is an interface of a file system that implements event notification in the computer system, wherein the event registration entry is a data structure providing a specifier of a file in the file system representing the event, and wherein the program instructions for maintaining retain the file in the file system and the specifier in the data structure while the file is not associated with the event identifier.

18. The computer program product of claim 17, wherein the program instructions for dissociating write an indication to the file that the event identifier has been dissociated, whereby an event consumer associated with the file is notified that the event identifier has been dissociated.

19. The computer program product of claim 18, wherein the program instructions for dissociating further write an indication of a particular action taken by the producer that caused removal of the event identifier.

20. The computer program product of claim 15, wherein the event is associated with a process, wherein the process is terminated causing the event identifier to become no longer valid, wherein a replacement process is spawned subsequent to termination of the process, and wherein the program instructions for second receiving receive the notification in response to spawning of the replacement process, wherein the process has a first process identifier wherein the replacement process has a second process identifier, and wherein the event identifier is the first process identifier and the new event identifier is the second process identifier.