Abstract:
A method, system, and computer program product for logging events in a data processing system is provided. In one embodiment, responsive to a determination that a situation exists preventing a primary logger from executing a logging task, a swappable adaptive logger is created, which in turn is pointed to a boot logger created by a swappable adaptive log engine. Event information is then logged to the boot logger. For example, the boot logger may write event information to memory or to a file if the logging database is unavailable. When the primary logger becomes configured and functional, the swappable adaptive logger swaps the boot logger for the primary logger and begins writing event information to the primary logger.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Technical Field  
           [0002]    The present invention relates generally to computer network environments, and more specifically to logging services in distributed, multilevel architectures.  
           [0003]    2. Description of Related Art  
           [0004]    Computers have come to epitomize modern life. Today, computers are used for much more than simply computing. For example, banking transactions are often conducted through automated teller machines (ATMs) connected via networks to central processing centers that keep track of transactions while computerized telephone switching systems manage the millions of calls generated each day. Furthermore, computers are integral to both peoples personal life as well as to their business life.  
           [0005]    As computers became more widespread in the workplace, new ways to harness their potential developed. Thus, with increasing use of computers for tasks other than simple computing has come an increase in complexity. Furthermore, as computers are increasingly networked together to provide even more functionality, that complexity is increased exponentially. To keep these networked computers operating and, therefore, ensure that ATM transactions, telephone calls, and business continue to operate smoothly, requires the work of administrators to monitor the systems and correct errors as they occur.  
           [0006]    One tool that aids administrators in keeping networks operational is logging. Logging is the process of recording system events so that those actions can be reviewed later. Thus, if an error occurs, that error may be logged with other information to allow an administrator to discover the source of the problem and correct it. However, currently, logging is not available during certain periods when the logging depends on a component that is not ready. This occurs during the time period prior to initialization of all the components needed, such as during hardware firmware BIOS boot, native OS boot, JVM boot, ORB boot, prior to initialization of components needed by the logging system, and during initialization of the logging system. This state also occurs during the time period for which the network has failed or some other failure event yields component dependencies. Another situation in which logging messages to a logging component cannot be accomplished is when the caller is not allowed to call the callee. This is to prevent the case where one component that is used by logging is not reentrant (config calls logger which calls config). Global locking approach until all dependencies are satisfied is not an option since messages are desired from all components in all stages of a distributed boot of kernel services. Therefore, it would be desirable to have a logging system that is capable of logging during initialization periods and situations in which the a component cannot be called by the logger.  
         SUMMARY OF THE INVENTION  
         [0007]    The present invention provides a method, system, and computer program product for logging events in a data processing system. In one embodiment, responsive to a determination that a situation exists preventing a primary logger from executing a logging task, a swappable adaptive logger is created, which in turn is pointed to a boot logger created by a swappable adaptive log engine. Event information is then logged to the boot logger. For example, the boot logger may write event information to memory or to a file if the logging database is unavailable. When the primary logger becomes configured and functional, the swappable adaptive logger swaps the boot logger for the primary logger and begins writing event information to the primary logger.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:  
         [0009]    [0009]FIG. 1 depicts a pictorial representation of a network of data processing systems in which the present invention may be implemented;  
         [0010]    [0010]FIG. 2 depicts a block diagram of a data processing system that may be implemented as a server in accordance with a preferred embodiment of the present invention;  
         [0011]    [0011]FIG. 3 depicts a block diagram illustrating a data processing system is depicted in which the present invention may be implemented;  
         [0012]    [0012]FIG. 4 depicts a block diagram of a logging subsystem in accordance with the present invention;  
         [0013]    [0013]FIG. 5 depicts a process flow and program function for determining when to use a boot logger in accordance with the present invention;  
         [0014]    [0014]FIG. 6 depicts a process flow and program function in a SLE for determining whether a boot logger should be created in accordance with the present invention;  
         [0015]    [0015]FIG. 7 depicts a process flow and program function for creating boot logger in accordance with the present invention;  
         [0016]    [0016]FIG. 8 depicts an exemplary process flow and program function illustrating when the swappable adaptive logger should switch to the fully configured and functional logger in accordance with the present invention; and  
         [0017]    FIGS.  9 A- 9 C depict block diagrams illustrating three possible states of the data processing system for logging purposes in accordance with the present invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0018]    With reference now to the figures, FIG. 1 depicts a pictorial representation of a network of data processing systems in which the present invention may be implemented. Network data processing system  100  is a network of computers in which the present invention may be implemented. Network data processing system  100  contains a network  102 , which is the medium used to provide communications links between various devices and computers connected together within network data processing system  100 . Network  102  may include connections, such as wire, wireless communication links, or fiber optic cables.  
         [0019]    In the depicted example, a plurality of servers  103 - 104  is connected to network  102  along with storage unit  106 . In addition, clients  108 ,  110 , and  112  are connected to network  102 . These clients  108 ,  110 , and  112  may be, for example, personal computers or network computers. In the depicted example, server  104  provides data, such as boot files, operating system images, and applications to clients  108 - 112 . Clients  108 ,  110 , and  112  are clients to servers  103 - 104 . Network data processing system  100  may include additional servers, clients, and other devices not shown. In the depicted example, network data processing system  100  is the Internet with network  102  representing a worldwide collection of networks and gateways that use the TCP/IP suite of protocols to communicate with one another. At the heart of the Internet is a backbone of high-speed data communication lines between major nodes or host computers, consisting of thousands of commercial, government, educational and other computer systems that route data and messages. Of course, network data processing system  100  also may be implemented as a number of different types of networks, such as for example, an intranet, a local area network (LAN), or a wide area network (WAN). FIG. 1 is intended as an example, and not as an architectural limitation for the present invention.  
         [0020]    Referring to FIG. 2, a block diagram of a data processing system that may be implemented as a server, such as servers  103 - 104  in FIG. 1, is depicted in accordance with a preferred embodiment of the present invention. Data processing system  200  may be a symmetric multiprocessor (SMP) system including a plurality of processors  202  and  204  connected to system bus  206 . Alternatively, a single processor system may be employed. Also connected to system bus  206  is memory controller/cache  208 , which provides an interface to local memory  209 . I/O bus bridge  210  is connected to system bus  206  and provides an interface to I/O bus  212 . Memory controller/cache  208  and I/O bus bridge  210  may be integrated as depicted.  
         [0021]    Peripheral component interconnect (PCI) bus bridge  214  connected to I/O bus  212  provides an interface to PCI local bus  216 . A number of modems may be connected to PCI local bus  216 . Typical PCI bus implementations will support four PCI expansion slots or add-in connectors. Communications links to clients  108 - 112  in FIG. 1 may be provided through modem  218  and network adapter  220  connected to PCI local bus  216  through add-in boards.  
         [0022]    Additional PCI bus bridges  222  and  224  provide interfaces for additional PCI local buses  226  and  228 , from which additional modems or network adapters may be supported. In this manner, data processing system  200  allows connections to multiple network computers. A memory-mapped graphics adapter  230  and hard disk  232  may also be connected to I/O bus  212  as depicted, either directly or indirectly.  
         [0023]    Those of ordinary skill in the art will appreciate that the hardware depicted in FIG. 2 may vary. For example, other peripheral devices, such as optical disk drives and the like, also may be used in addition to or in place of the hardware depicted. The depicted example is not meant to imply architectural limitations with respect to the present invention.  
         [0024]    The data processing system depicted in FIG. 2 may be, for example, an IBM e-Server pSeries system, a product of International Business Machines Corporation in Armonk, N.Y., running the Advanced Interactive Executive (AIX) operating system or LINUX operating system.  
         [0025]    With reference now to FIG. 3, a block diagram illustrating a data processing system is depicted in which the present invention may be implemented. Data processing system  300  is an example of a client computer. Data processing system  300  employs a peripheral component interconnect (PCI) local bus architecture. Although the depicted example employs a PCI bus, other bus architectures such as Accelerated Graphics Port (AGP) and Industry Standard Architecture (ISA) may be used. Processor  302  and main memory  304  are connected to PCI local bus  306  through PCI bridge  308 . PCI bridge  308  also may include an integrated memory controller and cache memory for processor  302 . Additional connections to PCI local bus  306  may be made through direct component interconnection or through add-in boards. In the depicted example, local area network (LAN) adapter  310 , SCSI host bus adapter  312 , and expansion bus interface  314  are connected to PCI local bus  306  by direct component connection. In contrast, audio adapter  316 , graphics adapter  318 , and audio/video adapter  319  are connected to PCI local bus  306  by add-in boards inserted into expansion slots. Expansion bus interface  314  provides a connection for a keyboard and mouse adapter  320 , modem  322 , and additional memory  324 . Small computer system interface (SCSI) host bus adapter  312  provides a connection for hard disk drive  326 , tape drive  328 , and CD-ROM drive  330 . Typical PCI local bus implementations will support three or four PCI expansion slots or add-in connectors.  
         [0026]    An operating system runs on processor  302  and is used to coordinate and provide control of various components within data processing system  300  in FIG. 3. The operating system may be a commercially available operating system, such as Windows 2000, which is available from Microsoft Corporation. An object oriented programming system such as Java may run in conjunction with the operating system and provide calls to the operating system from Java programs or applications executing on data processing system  300 . “Java” is a trademark of Sun Microsystems, Inc. Instructions for the operating system, the object-oriented operating system, and applications or programs are located on storage devices, such as hard disk drive  326 , and may be loaded into main memory  304  for execution by processor  302 .  
         [0027]    Those of ordinary skill in the art will appreciate that the hardware in FIG. 3 may vary depending on the implementation. Other internal hardware or peripheral devices, such as flash ROM (or equivalent nonvolatile memory) or optical disk drives and the like, may be used in addition to or in place of the hardware depicted in FIG. 3. Also, the processes of the present invention may be applied to a multiprocessor data processing system.  
         [0028]    As another example, data processing system  300  may be a stand-alone system configured to be bootable without relying on some type of network communication interface, whether or not data processing system  300  comprises some type of network communication interface. As a further example, data processing system  300  may be a personal digital assistant (PDA) device, which is configured with ROM and/or flash ROM in order to provide non-volatile memory for storing operating system files and/or user-generated data.  
         [0029]    The depicted example in FIG. 3 and above-described examples are not meant to imply architectural limitations. For example, data processing system  300  also may be a notebook computer or hand held computer in addition to taking the form of a PDA. Data processing system  300  also may be a kiosk or a Web appliance.  
         [0030]    The present invention provides a logging system with distributed, multilevel architecture which allows remote control of logging elements. The present invention also allows the logging system to be used standalone or in a distributed environment. The logging system allows a system to produce large amounts of data for local consumption, as opposed to a small amount of data for storage in a central remote repository. Dual output is easily configured for an administrator wishing to see logs on the console, in multiple files and in a database for future queries.  
         [0031]    With reference now to FIG. 4, a block diagram of a logging subsystem is depicted in accordance with the present invention. The logging subsystem  400  uses several objects to record system events. These objects include loggers  415 , logging handlers  424 , logging filters  420  (also referred to as masks), and logging formatters  418 . Log subsystem  400  also includes, a logging console administrator graphical user interface (GUI)  414 , a logging manager  422 , logging output  438 , a swappable adaptive logging engine (SLE)  450 , and swappable event policy (SEP)  452 .  
         [0032]    The swappable adaptive logging engine  450  creates a swappable adaptive logger  454  which is accessed by an application program to perform logging functions during boot time and other times when a fully configured and functional logger is not available, such as, for example, due to the fact that the database  442  has not finished being configured during initialization. The swappable adaptive logger points to a boot logger  411 - 412  during these times when the fully configured and functional logger  416 - 417  is not available and when the fully configured and functional logger  416 - 417  becomes available, the swappable adaptive logger is switched to point at the fully configured and functional logger  416 - 417 . However, to the application program this switching between loggers is invisible. The application program continues to point to the swappable adaptive logger. SEP  452  determines when a swappable adaptive logger  454  should be created and when the swappable adaptive logger should switch between a boot logger  411 - 412  and a fully configured and functional logger  416 - 417 .  
         [0033]    Loggers  415  are software objects that record events that occur while a component is operating. The Logging subsystem  400  supports two types of loggers  415 : message loggers  416  and trace Loggers  417 . Message loggers  416  are used to record textual messages from a component. These messages are internationalized for individual locales. Trace loggers  417  are used to capture information about the operating environment when component code fails to operate as intended. Support personnel use the information captured by trace loggers  417  to trace a problem to its source or to determine why an error occurred. Generally, this information is not enabled by default. Because trace messages are intended for support personnel, they are generally written to a file that can be viewed during a postmortem Examination. Additionally, logger  415  includes a boot message logger  411  and a boot trace logger  412  which are created and used by the swappable adaptive logger  454  when a fully configured and functional logger is not available.  
         [0034]    Handlers  424  are software objects that direct messages recorded by a logger to a logging output  438  destination. Messages can be directed to a file  444 , a database  442 , a console screen  440 , or to other destinations. One associates handlers  424  with loggers  415  to send information recorded by a logger  415  to the desired destination. The present invention provides the configuration definitions for the following types of handlers:  
         [0035]    Console Handler  426  writes log records to a console.  
         [0036]    File Handler  428  writes log records to a file.  
         [0037]    Multifile Handler  430  writes log records to a rotating set of log files.  
         [0038]    Serial File Handler  432  writes log records to files as serialized objects.  
         [0039]    Database Handler  434  writes log records to a database.  
         [0040]    Server Handler  436  sends log records in batch mode to a remote logging server for processing.  
         [0041]    Boot Handler  437  writes log records to a file or to memory.  
         [0042]    Filters  420  can be applied to loggers, to handlers  424 , or to both loggers and handlers. When applied to a logger, the filter determines which types of message and trace records the logger  415  processes. When applied to a handler  424 , the filter  420  determines which types of message and trace records the handler  424  sends to a destination. Filters  420  work by comparing a log record type against a set of criteria, or a query, contained within the filter.  
         [0043]    Formatters  418  are software objects used to format the output of information contained in log records. In general, formatters  418  can be used to tailor things like date and time stamps to local conventions. A single formatter  418  can be used by multiple handlers  424 . Having numerous loggers  416 , handlers  424 , filters  420 , and formatters  418  can cause an undue amount of logging administration to perform. To reduce the administration burden, one can create “groups”.  
         [0044]    A group contains loggers, handlers, filters, or formatters that have common properties. By creating groups, a newly created logger, handler, filter, or formatter with unset properties can inherit values for those properties from the group. If a logger, handler, filter, or formatter belongs to a group and its properties are updated, all other loggers, handlers, filters or formatters in that group will also have that property updated. This eliminates the need for manually updating individual logger, handler, filter, or formatter properties.  
         [0045]    The logging manager  422  provides an interface to Object Request Brokers (ORBs) as well as configuration and other DKS services. (An ORB is software that handles the communication of messages from a requesting program (client) to the object as well as any return values from the object back to the calling program.) The logging console Graphical User Interface (GUI) provides an interface to allow an administrator to provide configuration information as well as to output messages to the administrator.  
         [0046]    With reference now to FIG. 5, a process flow and program function for determining when to use a swappable adaptive logger is depicted in accordance with the present invention. To begin, Distributed Kernel Services (DKS) begins distributed logging boot after the hardware, operating system (OS), and Java Virtual Machine (JVM) have booted (e.g. initialized) (step  502 ). Next, if a configuration component in the initialization step desires to perform trace logging (step  504 ), then the configuration component calls the log manager to obtain a trace logger (step  506 ). The log manager calls the SLE to determine if a swappable adaptive logger is needed (step  508 ). The SLE checks swappable event policy (SEP) for creating a swappable adaptable logger and evaluates each case (step  510 ). Next, it determines whether a swappable adaptive logger needs to be created (step  512 ). If a swappable adaptive logger is needed, create it, otherwise proceed with logging in a normal fashion (step  520 ). If a boot logger and boot handler have been created and the handler attached to the boot logger, then the SLE starts the SEP which determines when the swappable adaptive logger should swap the boot logger for a fully functioning logger, such as, for example, message logger  416  or trace logger  417  (step  514 ). The SLE then returns the swappable trace logger to the log manager (step  516 ) and the log manager returns the trace logger to the configuration component (step  518 ).  
         [0047]    With reference now to FIG. 6, a process flow and program function in a SLE for determining whether a boot logger should be created is depicted in accordance with the present invention. The processes and functions depicted in FIG. 6 provide more details about steps  510 - 512  in FIG. 5. To begin, the SLE checks the policy for creating a boot logger (step  602 ). The SLE determines whether the logger will call the callee (step  604 ). If yes, then the SLE creates a boot logger (step  610 ).  
         [0048]    If the SLE determines that the logger will not call the callee, then the SLE determines whether the logger is not fully initialized (step  606 ). This may occur, for example, when the configuration is not available of it the database in not ready. For example, if the database is not ready, then a file or memory may be used instead. If the SLE determines that the logger is not fully initialized, then the SLE creates a boot logger (step  610 ). If the SLE determines that the logger is fully initialized, then the SLE determines whether all components needed by the logger are functional (step  608 ). If not all components needed by the logger are functional, then the SLE creates a boot logger (step  610 ). If all components needed by the logger are functional, then a boot logger is not created.  
         [0049]    With reference now to FIG. 7, a process flow and program function for creating a boot logger is depicted in accordance with the present invention. To begin, the SLE creates a boot logger without configuration (step  720 ) and the creates a boot handler without configuration (step  722 ). The boot handler is then attached to the boot logger (step  724 ) and the boot logger assigned to be used by the swappable adaptive logger (step  726 ).  
         [0050]    With reference now to FIG. 8, an exemplary process flow and program function for changing from the swappable adaptive logger to the fully configured and functional logger is depicted in accordance with the present invention. To begin, the SLE receives an SEP event (step  802 ). An SEP event is an event which indicates that the logger is fully configured. For example, an SEP event could be that the logging output database has been initialized. A message logger is then created from configuration data (step  804 ). The swappable adaptive logger is then pointed (i.e. switched) from the boot logger to the message logger (step  806 ). Thus, the boot logger has been replaced by the message logger.  
         [0051]    Alternatively, the process can be implemented in reverse. In this case, an SEP event is an event that indicates that the logger is not fully configured. For example, an event indicating that a component requesting logging will itself be called by the logger. In that case the logger may not be used, but rather a swappable logger must be used instead that does not need to call the callee. Thus, if an SEP event indicating that the logger is no longer fully configured is received, then the swappable adaptive logger is then pointed from the message logger to the boot logger.  
         [0052]    With reference now to FIGS.  9 A- 9 C, block diagrams illustrating three possible states of the data processing system for logging purposes are depicted in accordance with the present invention. FIG. 9A depicts possible state  0  in which the logger is not fully configured and functional. The JVM is running  900  and an application  902  calls a log manager API  904  that creates a swappable adaptive logger  906  using the log SLE. The SLE creates boot logger  908 , a boot handler memory  910 , attaches boot logger  908  to boot memory handler  910 , and assigns the boot logger  908  to the swappable adaptive logger  906 . Boot memory handler  910  provides an interface to input/output. In possible state  0 , the logging database has not been configured nor has the file system, thus, boot memory handler  910  provides an interface to memory  912  and boot logger  908  writes trace or message logs, as the case may be, to memory  912 . Once the file system has been initialized, the contents of memory  912  may be copied into file  914 , or alternatively, once a fully configured and functional logger  920  is available, the contents of memory  912  may be copied into database  928 .  
         [0053]    In FIG. 9B, possible state  1  shows an identical situation to possible state  0  except that in this case, the file system has been initialized. Thus, swappable adaptive logger  906  now points to boot logger  909  which includes a boot file handler  911 . Thus, boot file handler  911  provides an interface to file  914  and boot logger  909  writes logs to file  914 . Once the fully configured and functional logger  920  is available, the  4 : contents of file  914  may be copied into database  928 .  
         [0054]    In FIG. 9C, possible state  2  is illustrated. In this situation, the logging system is fully configured and functional. The JVM  900  is running as are the ORB services  930  and the configuration services  932 . The swappable adaptive logger  906  now points to the fully configured functional logger  920  rather than the boot logger  908 . The fully configured functional logger  920  includes a server handler  922  that provides and interface between the fully configured functional logger  920  and a logging console GUI  924 . The fully configured functional logger  920  also includes a database handler  926  that provides an interface between the fully configured functional logger  920  and a logging database  928 . Thus, logging information may be written to database  928  and also may be presented to a user through logging console GUI  924 .  
         [0055]    Therefore, the application always points to the swappable adaptive logger  906  and does not need to make any changes based on the status of the system. All changes to loggers are performed by the swappable adaptive logger  906 . The swappable adaptive logger  906  points to various loggers based on the status of the system. Thus, when the file system and database are not available, the swappable adaptive logger  906  points to a boot logger that is attached to a boot memory handler  910  for writing log information to memory  912  as depicted in FIG. 9A. When the file system becomes available, the swappable adaptive logger swaps boot logger  908  for boot logger  909  which is attached to boot file handler  911  for writing log information to file  914  as depicted in FIG. 9B. When the logging system is completely configured and functional as depicted in FIG. 9B, the swappable adaptive logger switches from boot logger  909  to fully configured functional logger  920 , thus allowing use of the database  928  and logging console GUI  924 .  
         [0056]    It is important to note that while the present invention has been described in the context of a fully functioning data processing system, those of ordinary skill in the art will appreciate that the processes of the present invention are capable of being distributed in the form of a computer readable medium of instructions and a variety of forms and that the present invention applies equally regardless of the particular type of signal bearing media actually used to carry out the distribution. Examples of computer readable media include recordable-type media, such as a floppy disk, a hard disk drive, a RAM, CD-ROMs, DVD-ROMs, and transmission-type media, such as digital and analog communications links, wired or wireless communications links using transmission forms, such as, for example, radio frequency and light wave transmissions. The computer readable media may take the form of coded formats that are decoded for actual use in a particular data processing system.  
         [0057]    The description of the present invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to best explain the principles of the invention, the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.