Using the CIM/XML Pull Operations STATUS <<< The TODO section is being maintained during the review and checkin process to keep track of problems, errors, notes, etc. Must be deleted before checkin to head of tree. Please feel free to add notes, etc in this section as you review/test.>>>>>> NOTES On working with task branch. Merge out Process To keep our TASK branch in sync with the current head of tree we need to do a regular merge out. the TaskMakefile contains the makefile procedures to do this efficiently. NOTE: Following these procedures is important in that you are merging out new material each time you do the merge out. If you were just to repeatedly merge out, you would be merging previously merged changes a second time causing a real mess. Start with new directory and put TaskMakefile above pegasus (needed so you have this file for the initial operations. make -f TaskMakefile branch_merge_out BNAME=PEP317-pullop ## takes a long time This checks out current head, merges it into task branch and sets tags for the mergeout. Note that at the end of this step this work is part of the TASK... branch. NOW check for conflicts, errors, etc. that resulted from the merge. Look for conflict flags, compare the results (I use linux merge as a good graphic compare tool) and build and test. When you are satisfied that the merge out is clean, you can commit the results to the TASK... branch To commit the work to this into Task branch make -f mak/TaskMakefile branch_merge_out_commit BNAME=PEP317-pullop or manually commit and finish as follows cvs commit make -f mak/TaskMakefile branch_merge_out_finish BNAME=PEP317-pullop ## This last step is important since it cleans up temporary tags to prepare you for the next checkout COMPARE TASKBRANCH WITH HEAD In a new pegasus work space do same as above for merge out. make -f TaskMakefile BNAME=PEP317-pullop This produces a result which is all of the head merged into the branch. A diff of this is all the new changes to the head of tree that you will include into the merge. TODO list: 1. Binary operation from OOP. Need to add counter to binary protocol to be able to count objects in response. Generates warnings in things like messageserializer and does not work with OOP right now. 2. OpenExecQuery - Code is incorrect in that it used InstancesWithPath where the spec is instances with no path. Need new function to wrap getInstanceElement(withoutPathElement) in XmlReader. Note that Alternate is to put flag on InstancesWith Path to say no path 3. Code for Pull part of OpenQueryInstancesRequest a) should be part of the common CIMOperationRequestDispatcher execCommon code. 4. The changes to WQLCIMOperationRequestDispatcher and CQL... for handling pull not completed so we feed the responses back to the EnmerationContext queues 3. Lots of minor TODOs, etc. 4. External runtime variables. Decide this as part of PEP. The variables exist in CIMOperationRequestDispatcher but not in CIMConfig. The primary ones to consider are: a. System maxObjectCount. Setting some maximum size on what a pull client can request (i.e. the maximum size of the maxObjectCount on Open... and pull operations. b. Pull interoperationTimeout (max times between operations). This is the maximum number of seconds on the operationTimeout parameter of the Open operations c. Maximum size of the responseCache before it starts backing up responses to the providers. 5. Decision on EnumerationContext timeout (separate thread or just checks during other operations). Can we, in fact really keep the enumeration context table and queue under control without monitoring with a separate thread. We must monitor for: a. Client operation that stop requesting (i.e. inter operation time exceeds operationTimeout). Note that if it simply exceeds the time the next operation does the cleanup. The issue is those clients that simply stop and do not either close or go to completion. b. We should protect against providers that no not every finish delivering or take to long between deliveries. This does not exist in Pegasus today 6. Clean up code in Dispatcher. The associators code is still real mess and the pull code is in a template. The Pull code is good now but must be duplicated. Look at creating new CIMMessage CIMPullResponseMessage so that we can have common code. Everything is the same except what goes into the CIMResponseData so it is logical to have completely common processing 7. Extension to avoid double move of objects in CIMResponseData (one into enumerationContext queue and second to new cimResponseData for response. Want to avoid second move by extending Open/Pull response messages to include count and CIMResponse data to count objects out of queue when converting (avoids the second move). Big issue here with binary data since need to extend format to count it. 8. Still using templates, etc. in code in the Dispatcher. This is for all of the open operations where there is a lot of duplicate code and the pull operations that are 99% duplicate code (in a single template) Fixed for 9 June CVS update 1. Cleaned up code for OpenQueryInstances. Note that this is incomplete. No support in WQL or CQL Operations 2. What was fixed for 5 June checkin. 1. Extended ResponseTest MOF for for both CMPI and C++ subclasses 2. Fixed issues with pullop. 3. Fixed temp issue with CIMResponseData size by putting in mutex. That is not a permanent fix but it gets around issue probably in the control of the move logic that meant counts were off. 4. Fixed issues in Dispatcher so that associator code works. Still messy code in the dispatcher. 5. Changed name of Enumerationtable.h & cpp to EnumerationContextTable.* 6 Changed name of ResponseStressTest module, classes, etc. TAG: TASK_PEP317_5JUNE_2013_2 2 June 2013 Issues - KS 1. have not installed the binary move in CIMResponseData. Please run with OPP off. 2. Some problem in the processing so we are getting server crashes. Right no I am guessing that this is in the binaryCodec and am going to expand the test tools to allow testing through the localhost. 3. Still way to many TODO and KS comments and KS_TEMPS. Removing bit by bit. 4. Env variable connection for the config parameters not installed. 5. Issue with the threaded timer. For some reason during tests it eventually calls the timer thread with trash for the parm (which is pointer to the EnumerationTable object). Caught because we do a valid test at beginning of the function. 6. Still using the templates in CIMOperationRequestDispatcher to simplify the handle... processing. 7. I think I have a way around the double move of objects in the EnumerationContext so that the outputter will just take a defined number of objects directly from the gathering cache and save the second move. 8. Not yet passing all tests but getting closer now. 9. Created a tag before this commit TASK_PEP317_1JUNE_2013. 10. Next Tag will be TASK_PEP317_2_JUNE_2013 in the task branch =========================================== OVERVIEW: The operation extensions for pull operations defined in the DMTF specification DSP0200 V 1.4 were implemented in Pegasus effective Pegasus version 2.11 including Client and Server. These operations extend the CIM/XML individual operations to operation sequences where the server must maintain state between operations in a sequence and the client must execute multiple operations to get the full set of instances or instance paths. The following new CIM/XML operations as defined in DSP0200 are included; -OpenEnumerateInstances -openEnumerateInstancePaths -OpenReferenceInstances -OpenReferenceInstancePaths -OpenAssociatiorInstances -OpenAssociatorInstancePaths -PullInstancesWithPath -PullInstancePaths -CloseEnumeration -EnumerationCount OpenExecQuery The following operations have not been implemented in this version of Pegasus: -OpenQueryInstances The following limitations on the implementation exist; 1. The filterQueryLanguage and filterQuery parameters are processed by the Pegasus client but the server returns error if there is any data in either parameter. This work does not include the development of the query language. Note that a separate effort to extend Pegasus to use the DMTF FQL query language is in process. 2. The input parameter continueOnError is processed correctly by the client but the Pegasus server only provides for false since the server does not include logic to continue processing responses after an error is encountered. This is consistent with the statement in the specification that use of this functionality is optional and the fact that the DMTF agrees that all of the issues of continuing after errors have not been clarified. 3. The operation enumerationCount is not processed by the server today since a) really getting the count would be the same cost as the corresponding enumeration, b) the server does not include a history or estimating mechanism for this to date. NOTE: After a through review as part of the development of the next version of CMPI we have concluded that this operation is probably not worth the effort. Since it is optional, Pegasus will only return the unknown status at this point Since the concept of sequences of operations linked together (open, pull, close) is a major extension to the original CIM/XML operation concept of completely independent operations several new pieces of functionality are implemented to control interOperationTimeouts, counts of objects to be returned, etc. TBD - Review this CLIENT The new operations follow the same pattern as the APIs for existing operations in that: 1. All errors are handled as CIMException and Exception 2. The means of inputting parameters are the same except that there are significantly more input parameters with the open operations and for the first time operations return parameters as well as objects in the response. Specifically the open and pull operations return values for enumerationContext which is the identity for a pull sequence and endOfSequence which is the marker the server sends in open and pull responses when it has no more objects to send. The significant differences include: 1. Processing of parameters on responses (i.e. the endOfSequence and enumerationContext parameters are returned for open and pull operations). 2. Numeric arguments (Uint32 and Uint64 include the option of NULL in some cases so they are packaged inside classes Uint32Arg and Uint64Arg in the client api. 3. The association and reference operations ONLY process instances. They do not include the capability to return classes like reference and associator do and therefore return CIMInstance rather than CIMObject. 4. Paths are returned in all cases (i.e OpenEnumerateInstances and PullInstancesWithPath where they were not with EnumeratInstances. 5. The client must maintain state between operations in a sequence (using the enumerationContext parameter). TBD- Are there more differences. SERVER The Pegasus server attempts to always deliver the requested number of objects for any open or pull request (the specification allows for the server to deliver less than the requested number of objects and specifically to return zero objects on open). We felt that it was worth any extra cost in processing to provide the client with exactly what it had requested. The pegasus server always closes an enumeration sequence upon receipt of any error from the providers, repository, etc. Therefore the server will reject any request that has continueOnError = true; Expansion to allow the continue on error may be added in a future version. In any case, the whole purpose of the continue on error is really to allow input from good providers to be mixed with providers that return errors so that generally this would mean simply changing the logic in the return mechanism to not shutdown when an error is received from any given provider. Generally we do not believe that the providers need to do much more in the future to support the continueOnError other than possibly allowing the provider to continue processing after it has received an error. PROVIDERS This implementation requires NO changes to the existing providers. The provider APIs operate just as they do with the original operations. Because the server processing is different however, there may be some behavior differences primarily because the client now controls the speed of delivery of objects. In previous versions of Pegasus, the server attempts to deliver objects as rapidly as then can be put on the network. In the case of HTTP chunked requests they are delivered in chunks of about 100 objects. The primary delay for the providers was the processing of each segment through the server. The server is blocked so that no other segment can proceed through the server until that segment is processed and sent on the network. In the case of non-chunkedresponses, they are completely gathered in the serve and then delivered as one non-chunked response. There were no delays for the providers, just lots of possible memory use in the server. The responses from providers (delivered through the deliver(...) interface are gathered into segments of about 100 objects and this group of objects is moved through the server to be delivered to the client. However with the inclusion of the pull operations, The segments of objects from the providers are cached in the server response path until the maxObjectCount for that request (open or pull) and that number returned in a non-chunked response. Thus, if the client is slow to issue pull requests, the providers might be delayed at some point to reduce memory usage in the server (the delay appears as slow response tothe deliver operation). In other words, the time to process large sets of responses from the provider now depends on the speed of handling the client. It is important to remember in developing providers that the Pegasus server can most efficiently process responses if they are passed from the provider to the server individually or in small arrays of objects rather than the provider gathering very large arrays of objects and sending them to the server. NEXT GENERATION PROVIDERS KS_TODO CONFIGURATION PARAMETERS The server includes several configuration parameters to set limits on the processing of pull operations. All of these configuration parameters are compile time parameters rather than runtime. 1. Maximum value of minimum interoperation time. This parameter defines the maximum time allowed between the return of an open or pull response and the receipt of the next pull or a close operation before the server may close the enumeration. The specification allows the server to set a maximum interoperation time and refuse open requests that with requested operationTimeout greater than that time. CIM_ERR_INVALID_OPERATION_TIMEOUT This value is set with the Pegasus environment variable PEGASUS_PULL.... 2. Maximum objects returned in a single open or pull operation. The server can set a maximum limit on the number of objects that can be returned in a single open or pull oepration with the maxObjectCount parameter. 3. Whether the server allows 0 as an interoperation timeout value. The value zero is s special value for the interoperationTimeout in that it tells the server to not timeout any enumeration sequence. With this value for interoperationTimeout, the only way to close an enumeration sequence is to complete all of the pulls or issue the close. If for some reason the sequence is not completed, that enumeration context would remain open indefinitly. Since in Pegasus any open enumeration context uses resources (the context object and any provider resposnes that have not yet been issued in a response) it would appear that most platforms would not want to allow the existence of enumeration contexts that cannot be closed by the server. 4, maximum consecutive pull requests with 0 maxObjectCount. The use of the pull operation with maxObjectCount set to zero could be used to keep an enumeration context open indefinitly (this tells the server to restart the interoperationTimeout but not send any objects in the response). Therefore the specification allows for the server setting maximum limits on this behavior and returning the error CIM_ERR_SERVER_LIMITS_EXCEEDED if this limit is exceeded. Note that this is maximum CONSECUTIVE pulls so that issuing a pull with a non-zero count resets this counter. KS-TBD - Is this really logical since we can still block by just issuing lots of zero request and an occansional request for one object. Pegaus sets the value of this limit to 1000 and allows the implementer to modify it with the PEGASUS_MAXIMUM_ZERO_OBJECTCOUNT environment variable. 5. Default operationTimeout - The default of this parameter is to refuse operat In the current release of Pegasus these are all compile time parameters.