METHOD FOR SINGLETON PROCESS CONTROL

• US 20160004560A1
• Filed: 09/10/2015
• Published: 01/07/2016
• Est. Priority Date: 01/21/2008
• Status: Active Grant

• Current Assignee: AirBNB Incorporated
• Original Assignee: International Business Machines Corporation
• Inventors: ACEDO, Mario F., CERVANTES, Ezequiel, JENNAS, Paul A. II, PEIPELMAN, Jason L., WARD, Matthew J.
• Granted Patent: US 9,612,864 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 9/445 Program loading or initiating bootstrapping G06F9/4401; security arrangements for program loading or initiating G06F21/57
• CPC Class Codes: G06F 9/48 Program initiating; Program switching, e.g. by interrupt

Abstract

A method for singleton process control in a computer environment is provided. A process identification (PID) for a background process is stored in a first temporary file. A determination operation is performed for determining if the parent process is alive for a predetermined number of tries. The PID of the background process is written from the first temporary file into a first PID variable when the parent process ends. A determination operation is performed for determining whether a second, global temporary file is empty. The background process is exited if an active PID is determined to exist in a second, global temporary file. The PID from the first temporary file is stored into the second, global temporary file. A singleton code block is then executed.

Claims

1. A method for singleton process control in a computer environment, comprising:

storing a process identification (PID) of a last spawned process for a background process in a first temporary file, the PID stored by a parent process, and subsequently accessed by the background process that is initialized;

determining if the parent process is alive for a predetermined number of tries, wherein a PID of the background process is written from the first temporary file into a first PID variable when the parent process ends;

determining whether a second, global temporary file is empty, wherein;

if the global temporary file is empty;

commencing for a first time an associated program with the PID of the background process if a second, global temporary file is empty, and

storing the PID of the background process from the first temporary file into the second, global temporary file; and

writing the existing PID to a second PID variable.

2. The method of claim 1, further including:

initializing a background process variable for keeping track of the predetermined number of tries the parent process is checked to determine if the parent process is alive,

storing into the background process variable for so long as the parent process is active,

executing a singleton code block; and

if the global temporary file is not empty;

determining if an existing PID stored within the second, global temporary file is active, wherein

if the existing PID is determined to be active in the second, global temporary file, exiting a process associated with the existing PID, and

if the existing PID is determined to be not active in the second, global temporary file, storing the PID of the background process from the first temporary file into the second, global temporary file.

3. The method of claim 1, further including, previous to storing the PID from the first temporary file into the second, global temporary file, determining if the second, global temporary file is empty.

4. The method of claim 1, further including creating the first temporary file.

5. The method of claim 4, further including creating the second, global temporary file.

6. The method of claim 5, further including starting the background process.

7. The method of claim 6, further including:

initializing a background process variable,

determining if the parent process is alive for a predetermined number of tries, and

storing into the background process variable for so long as the parent process is active.

8. The method of claim 7, further including if the predetermined number of tries is reached:

sleeping for a predetermined time, and

redetermining if the parent process is alive for the predetermined number of tries.

9. The method of claim 8, further including ensuring only one instance of the associated program is started by using the PID of the background process and not using program names, wherein a wrapper script returns a prompt to a user as calls to start a program as the parent process dies.

10. A system for singleton process control in a computing environment, the system comprising:

a plurality of files in the computing system;

at least one memory in the computing system; and

at least one processor device operable in the computing environment the singleton process control in communication with the plurality of files and the at least one memory, wherein the at least one processor device;

stores a process identification (PID) of a last spawned process for a background process in a first temporary file, the PID stored by a parent process, and subsequently accessed by the background process that is initialized,

determines if the parent process is alive for a predetermined number of tries, wherein a PID of the background process is written from the first temporary file into a first PID variable when the parent process ends, and

determining whether a second, global temporary file is empty, wherein;

if the global temporary file is empty;

commencing for a first time an associated program with the PID of the background process if a second, global temporary file is empty, and

storing the PID of the background process from the first temporary file into the second, global temporary file; and

writing the existing PID to a second PID variable.

11. The system of claim 10, wherein the at least one processor device that performs each one of:

initializes a background process variable for keeping track of the predetermined number of tries the parent process is checked to determine if the parent process is alive,

stores into the background process variable for so long as the parent process is active,

executing a singleton code block, and

if the global temporary file is not empty;

determining if an existing PID stored within the second, global temporary file is active, wherein

if the existing PID is determined to be active in the second, global temporary file, exiting a process associated with the existing PID, and

if the existing PID is determined to be not active in the second, global temporary file, storing the PID of the background process from the first temporary file into the second, global temporary file.

12. The system of claim 10, wherein the at least one processor device that, previous to storing the PID from the first temporary file into the second, global temporary file, determines if the second, global temporary file is empty.

13. The system of claim 10, wherein the at least one processor device that creates the first temporary file.

14. The system of claim 13, wherein the at least one processor device that creates the second, global temporary file.

15. The system of claim 14, wherein the at least one processor device that starts the background process.

16. The system of claim 15, wherein the at least one processor device that performs one of:

initializing a background process variable,

determining if the parent process is alive for a predetermined number of tries, and

storing into the background process variable for so long as the parent process is active.

17. The system of claim 16, wherein the at least one processor device that, if the predetermined number of tries is reached, performs each of:

sleeping for a predetermined time, and

redetermining if the parent process is alive for the predetermined number of tries.

18. The system of claim 17, wherein the at least one processor device that ensures only one instance of the associated program is started by using the PID of the background process and not using program names, wherein a wrapper script returns a prompt to a user as calls to start a program as the parent process dies.

19. A computer program product for singleton process control in a computer environment, the computer program product comprising a computer-readable storage medium having computer-readable program code portions stored therein, the computer-readable program code portions comprising:

a first executable portion that stores a process identification (PID) of a last spawned process for a background process in a first temporary file, the PID stored by a parent process, and subsequently accessed by the background process that is initialized;

a second executable portion that determines if the parent process is alive for a predetermined number of tries, wherein a PID of the background process is written from the first temporary file into a first PID variable when the parent process ends; and

a third executable portion that determines whether a second, global temporary file is empty, wherein;

if the global temporary file is empty;

commencing for a first time an associated program with the PID of the background process if a second, global temporary file is empty, and

storing the PID of the background process from the first temporary file into the second, global temporary file; and

writing the existing PID to a second PID variable.

20. The computer program product of claim 19, further including a fourth executable portion that performs at least one of:

initializes a background process variable for keeping track of the predetermined number of tries the parent process is checked to determine if the parent process is alive,

stores into the background process variable for so long as the parent process is active,

executing a singleton code block, and

if the global temporary file is not empty;

determining if an existing PID stored within the second, global temporary file is active, wherein

if the existing PID is determined to be active in the second, global temporary file, exiting a process associated with the existing PID, and

if the existing PID is determined to be not active in the second, global temporary file, storing the PID of the background process from the first temporary file into the second, global temporary file.

21. The computer program product of claim 19, further including a fourth executable portion that, previous to storing the PID from the first temporary file into the second, global temporary file, determines if the second, global temporary file is empty.

22. The computer program product of claim 19, further including a fourth executable portion that that creates the first temporary file.

23. The computer program product of claim 22, further including an fifth executable portion that that creates the second, global temporary file.

24. The computer program product of claim 23, further including a sixth executable portion that that starts the background process.

25. The computer program product of claim 24, further including a seventh executable portion that that performs each one of:

initializing a background process variable,

determining if the parent process is alive for a predetermined number of tries, and

storing into the background process variable for so long as the parent process is active.

26. The computer program product of claim 25, further including an eighth executable portion that, if the predetermined number of tries is reached, performs each of:

sleeping for a predetermined time, and

redetermining if the parent process is alive for the predetermined number of tries.

27. The computer program product of claim 26, further including a ninth executable portion that ensures only one instance of the associated program is started by using the PID of the background process and not using program names, wherein a wrapper script returns a prompt to a user as calls to start a program as the parent process dies.