1 karl 1.1.2.1 Using the CIM/XML Pull Operations
2
3 STATUS
4
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5 karl 1.1.2.4 <<< The TODO section is being maintained during the review and checkin process
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6 karl 1.1.2.1 to keep track of problems, errors, notes, etc. Must be deleted before
7 checkin to head of tree. Please feel free to add notes, etc in this
8 section as you review/test.>>>>>>
9
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10 karl 1.1.2.5 NOTES On working with task branch.
11
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12 karl 1.1.2.6 Merge out Process
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13 karl 1.1.2.5
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14 karl 1.1.2.6 To keep our TASK branch in sync with the current head of tree we need
15 to do a regular merge out. the TaskMakefile contains the makefile
16 procedures to do this efficiently. NOTE: Following these procedures is
17 important in that you are merging out new material each time you do
18 the merge out. If you were just to repeatedly merge out, you would be
19 merging previously merged changes a second time causing a real mess.
20
21 Start with new directory and put TaskMakefile above pegasus (needed so you
22 have this file for the initial operations.
23
24 make -f TaskMakefile branch_merge_out BNAME=PEP317-pullop ## takes a long time
25
26 This checks out current head, merges it into task branch and sets tags
27 for the mergeout. Note that at the end of this step this work is
28 part of the TASK... branch.
29
30 NOW check for conflicts, errors, etc. that resulted from the merge.
31 Look for conflict flags, compare the results (I use linux merge as a
32 good graphic compare tool) and build and test. When you are satisfied
33 that the merge out is clean, you can commit the results to the TASK...
34 branch
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35 karl 1.1.2.5
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36 karl 1.1.2.6 To commit the work to this into Task branch
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37 karl 1.1.2.5
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38 karl 1.1.2.6 make -f mak/TaskMakefile branch_merge_out_commit BNAME=PEP317-pullop
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39 karl 1.1.2.5
40 or manually commit and finish as follows
41
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42 karl 1.1.2.6 cvs commit
43 make -f mak/TaskMakefile branch_merge_out_finish BNAME=PEP317-pullop
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44 karl 1.1.2.5
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45 karl 1.1.2.6 ## This last step is important since it cleans up temporary tags to prepare
46 you for the next checkout
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47 karl 1.1.2.5
48 COMPARE TASKBRANCH WITH HEAD
49
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50 karl 1.1.2.7 In a new pegasus work space do same as above for merge out.
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51 karl 1.1.2.5
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52 karl 1.1.2.7 make -f TaskMakefile BNAME=PEP317-pullop
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53 karl 1.1.2.5
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54 karl 1.1.2.7 This produces a result which is all of the head merged into the branch.
55 A diff of this is all the new changes to the head of tree that you will
56 include into the merge.
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57 karl 1.1.2.5
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58 karl 1.1.2.3
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59 karl 1.1.2.4 TODO list:
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60 karl 1.1.2.3 1. Binary operation from OOP. Need to add counter to binary
61 protocol to be able to count objects in response. Generates
62 warnings in things like messageserializer and does not work with
63 OOP right now.
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64 karl 1.1.2.4 2. OpenExecQuery - Code is incorrect in that it used InstancesWithPath
65 where the spec is instances with no path. Need new function to wrap
66 getInstanceElement(withoutPathElement) in XmlReader. Note that
67 Alternate is to put flag on InstancesWith Path to say no path
68 3. Code for Pull part of OpenQueryInstancesRequest a) should be part of
69 the common CIMOperationRequestDispatcher execCommon code.
70 4. The changes to WQLCIMOperationRequestDispatcher and CQL... for handling
71 pull not completed so we feed the responses back to the EnmerationContext
72 queues
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73 karl 1.1.2.7 3. Lots of minor TODOs, diagnostics, etc.
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74 karl 1.1.2.4 4. External runtime variables. Decide this as part of PEP. The variables
75 exist in CIMOperationRequestDispatcher but not in CIMConfig. The primary
76 ones to consider are:
77 a. System maxObjectCount. Setting some maximum size on what a pull
78 client can request (i.e. the maximum size of the maxObjectCount on
79 Open... and pull operations.
80 b. Pull interoperationTimeout (max times between operations). This is
81 the maximum number of seconds on the operationTimeout parameter of the
82 Open operations
83 c. Maximum size of the responseCache before it starts backing up
84 responses to the providers.
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85 karl 1.1.2.3 5. Decision on EnumerationContext timeout (separate thread or just
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86 karl 1.1.2.4 checks during other operations). Can we, in fact really keep the
87 enumeration context table and queue under control without monitoring
88 with a separate thread. We must monitor for:
89 a. Client operation that stop requesting (i.e. inter operation time
90 exceeds operationTimeout). Note that if it simply exceeds the time
91 the next operation does the cleanup. The issue is those clients that
92 simply stop and do not either close or go to completion.
93 b. We should protect against providers that no not every finish delivering
94 or take to long between deliveries. This does not exist in Pegasus
95 today
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96 karl 1.1.2.8 6. Clean up code in Dispatcher. Want to at least reduce the code for the
97 Open Operations to a set of templates so we know that the code is the
98 same for all operations. Right now the existing operations enum, assoc,
99 etc. are all in templates but not the open operations. Note that the
100 pull is a single template for both pullInstances and pullInstancePaths.
101 However, we might be able to reduce this to a single function by adding
102 a new level to CIMMessage.h (CommonPullResponse)
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103 karl 1.1.2.3 7. Extension to avoid double move of objects in CIMResponseData (one
104 into enumerationContext queue and second to new cimResponseData for
105 response. Want to avoid second move by extending Open/Pull response
106 messages to include count and CIMResponse data to count objects out
107 of queue when converting (avoids the second move). Big issue here
108 with binary data since need to extend format to count it.
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109 karl 1.1.2.8 8. NEXT TASKS:
110 a. get the pull operations rather than a template into a single
111 function by creating a new CIMPullResponse message in CIMMessage.h that
112 contains the pull data. Then we can use a single function to process all
113 pull operations.
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114 karl 1.1.2.9 b. test the enumeration timeout thread
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115 karl 1.1.2.8 c. New Mergout to bring up to to date again.
116 d. Fix known problem with the interop provider.
117
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118 karl 1.1.2.9 17 September 2013 CVS update (Actually two different updates over 3 days)
119 1. Clean up some issues in CIMMessage.h and CIMMessage.cpp
120 2. Extend OpenExecQuery to WQL and CQL processors but return not complete
121 3. Remove memory leak in EnumerationContext and EnumerationContextTable
122 handling.
123 4. Created template functions for much of the pull operations.
124 5. Reversed order of queryLanguage and query (and changed names to match
125 execQuery) in client and server. Note that these are the execQuery
126 WQL and CQL filters and NOT FQL filters.
127 6. Some code cleanup in dispatcher
128 7. Today, passes all tests in pullop but issue in alltests. For some reason
129 not finding CIMObjectManager instance. Also, leaves enumeration contexts
130 if client terminates since cleanup thread not operating.
131
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132 karl 1.1.2.8 14 September 2013 CVS update
133 Merged out up to 25 August. Cleaned up all operations and standardized code.
134 At this point the non pull operations code is in a set of templates but the
135 pull is not yet.
136 Fixed a significant number of problems so that it appears that the operations
137 except for OpenExecQuery run stably, at least with the pullop test program.
138 Note that there is a problem in that the Interop control provider is not
139 returning its singleton wbemserver object for some reason. Causes a test
140 failure
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141 karl 1.1.2.7
142 Fixed for 16 June CVS Update
143 1. Cleaned up the enumerationContext and Table release functions and tested
144 to confirm that we do not lose memory in either normal sequences or
145 sequences that close early. Cleaned up pullop and added more tests
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146 karl 1.1.2.8 Taged Before: PREAUG25UPDATE and after POSTAUG25UPDATE
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147 karl 1.1.2.4
148 Fixed for 9 June CVS update
149 1. Cleaned up code for OpenQueryInstances. Note that this is incomplete.
150 No support in WQL or CQL Operations
151 2.
152
153 What was fixed for 5 June checkin.
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154 karl 1.1.2.3 1. Extended ResponseTest MOF for for both CMPI and C++ subclasses
155 2. Fixed issues with pullop.
156 3. Fixed temp issue with CIMResponseData size by putting in mutex. That
157 is not a permanent fix but it gets around issue probably in the control
158 of the move logic that meant counts were off.
159 4. Fixed issues in Dispatcher so that associator code works. Still messy
160 code in the dispatcher.
161 5. Changed name of Enumerationtable.h & cpp to EnumerationContextTable.*
162 6 Changed name of ResponseStressTest module, classes, etc.
163
164 TAG: TASK_PEP317_5JUNE_2013_2
165
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166 karl 1.1.2.2 2 June 2013
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167 karl 1.1.2.1
168 Issues - KS
169 1. have not installed the binary move in CIMResponseData. Please run
170 with OPP off.
171 2. Some problem in the processing so we are getting server crashes.
172 Right no I am guessing that this is in the binaryCodec and am going to
173 expand the test tools to allow testing through the localhost.
174
175 3. Still way to many TODO and KS comments and KS_TEMPS. Removing bit by bit.
176
177 4. Env variable connection for the config parameters not installed.
178
179 5. Issue with the threaded timer. For some reason during tests it
180 eventually calls the timer thread with trash for the parm (which is
181 pointer to the EnumerationTable object). Caught because we do a valid
182 test at beginning of the function.
183
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184 karl 1.1.2.2 6. Still using the templates in CIMOperationRequestDispatcher to simplify
185 the handle... processing.
186
187 7. I think I have a way around the double move of objects in the
188 EnumerationContext so that the outputter will just take a defined number
189 of objects directly from the gathering cache and save the second move.
190
191 8. Not yet passing all tests but getting closer now.
192
193 9. Created a tag before this commit TASK_PEP317_1JUNE_2013.
194
195 10. Next Tag will be TASK_PEP317_2_JUNE_2013 in the task branch
196
197
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198 karl 1.1.2.1 ===========================================
199
200 OVERVIEW:
201
202 The operation extensions for pull operations defined in the DMTF specification
203 DSP0200 V 1.4 were implemented in Pegasus effective Pegasus version 2.11
204 including Client and Server.
205
206 These operations extend the CIM/XML individual operations to operation
207 sequences where the server must maintain state between operations in a
208 sequence and the client must execute multiple operations to get the full
209 set of instances or instance paths.
210
211 The following new CIM/XML operations as defined in DSP0200 are included;
212
213 -OpenEnumerateInstances
214 -openEnumerateInstancePaths
215 -OpenReferenceInstances
216 -OpenReferenceInstancePaths
217 -OpenAssociatiorInstances
218 -OpenAssociatorInstancePaths
219 karl 1.1.2.1 -PullInstancesWithPath
220 -PullInstancePaths
221 -CloseEnumeration
222 -EnumerationCount
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223 karl 1.1.2.2 OpenExecQuery
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224 karl 1.1.2.1
225 The following operations have not been implemented in this version of Pegasus:
226
227 -OpenQueryInstances
228
229 The following limitations on the implementation exist;
230
231 1. The filterQueryLanguage and filterQuery parameters are processed by
232 the Pegasus client but the server returns error if there is any data in
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233 karl 1.1.2.2 either parameter. This work does not include the development of the
234 query language. Note that a separate effort to extend Pegasus to use
235 the DMTF FQL query language is in process.
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236 karl 1.1.2.1
237 2. The input parameter continueOnError is processed correctly by the client
238 but the Pegasus server only provides for false since the server does not
239 include logic to continue processing responses after an error is
240 encountered.
241 This is consistent with the statement in the specification that use of
242 this functionality is optional and the fact that the DMTF agrees that all
243 of the issues of continuing after errors have not been clarified.
244
245 3. The operation enumerationCount is not processed by the server today since
246 a) really getting the count would be the same cost as the corresponding
247 enumeration, b) the server does not include a history or estimating
248 mechanism for this to date.
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249 karl 1.1.2.2 NOTE: After a through review as part of the development of the next version
250 of CMPI we have concluded that this operation is probably not worth the
251 effort. Since it is optional, Pegasus will only return the unknown status
252 at this point
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253 karl 1.1.2.1
254 Since the concept of sequences of operations linked together (open, pull, close)
255 is a major extension to the original CIM/XML operation concept of completely
256 independent operations several new pieces of functionality are implemented
257 to control interOperationTimeouts, counts of objects to be returned, etc.
258
259 TBD - Review this
260
261 CLIENT
262
263 The new operations follow the same pattern as the APIs for existing operations
264 in that:
265
266 1. All errors are handled as CIMException and Exception
267
268 2. The means of inputting parameters are the same except that there are
269 significantly more input parameters with the open operations and for the
270 first time operations return parameters as well as objects in the
271 response. Specifically the open and pull operations return values for
272 enumerationContext which is the identity for a pull sequence and
273 endOfSequence which is the marker the server sends in open and pull
274 karl 1.1.2.1 responses when it has no more objects to send.
275
276 The significant differences include:
277
278 1. Processing of parameters on responses (i.e. the endOfSequence and
279 enumerationContext parameters are returned for open and pull operations).
280
281 2. Numeric arguments (Uint32 and Uint64 include the option of NULL in some
282 cases so they are packaged inside classes Uint32Arg and Uint64Arg in the
283 client api.
284
285 3. The association and reference operations ONLY process instances. They do
286 not include the capability to return classes like reference and associator
287 do and therefore return CIMInstance rather than CIMObject.
288
289 4. Paths are returned in all cases (i.e OpenEnumerateInstances and
290 PullInstancesWithPath where they were not with EnumeratInstances.
291
292 5. The client must maintain state between operations in a sequence (using
293 the enumerationContext parameter).
294
295 karl 1.1.2.1 TBD- Are there more differences.
296
297
298 SERVER
299
300 The Pegasus server attempts to always deliver the requested number of objects
301 for any open or pull request (the specification allows for the server to
302 deliver less than the requested number of objects and specifically to return
303 zero objects on open). We felt that it was worth any extra cost in processing
304 to provide the client with exactly what it had requested.
305
306 The pegasus server always closes an enumeration sequence upon receipt of any
307 error from the providers, repository, etc. Therefore the server will reject
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308 karl 1.1.2.2 any request that has continueOnError = true;
309
310 Expansion to allow the continue on error may be added in a future version.
311 In any case, the whole purpose of the continue on error is really to allow
312 input from good providers to be mixed with providers that return errors so
313 that generally this would mean simply changing the logic in the return mechanism
314 to not shutdown when an error is received from any given provider.
315
316 Generally we do not believe that the providers need to do much more in the
317 future to support the continueOnError other than possibly allowing the provider
318 to continue processing after it has received an error.
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319 karl 1.1.2.1
320 PROVIDERS
321
322 This implementation requires NO changes to the existing providers. The
323 provider APIs operate just as they do with the original operations.
324
325 Because the server processing is different however, there may be some
326 behavior differences primarily because the client now controls the speed of
327 delivery of objects.
328
329 In previous versions of Pegasus, the server attempts to deliver objects as
330 rapidly as then can be put on the network. In the case of HTTP chunked requests
331 they are delivered in chunks of about 100 objects. The primary delay for the
332 providers was the processing of each segment through the server. The server
333 is blocked so that no other segment can proceed through the server until that
334 segment is processed and sent on the network.
335 In the case of non-chunkedresponses, they are completely gathered in the serve
336 and then delivered as one non-chunked response. There were no delays for the
337 providers, just lots of possible memory use in the server.
338
339 The responses from providers (delivered through the deliver(...) interface are
340 karl 1.1.2.1 gathered into segments of about 100 objects and this group of objects is moved
341 through the server to be delivered to the client.
342
343 However with the inclusion of the pull operations, The segments of objects
344 from the providers are cached in the server response path until the
345 maxObjectCount for that request (open or pull) and that number returned in a
346 non-chunked response. Thus, if the client is slow to issue pull requests,
347 the providers might be delayed at some point to reduce memory usage in the
348 server (the delay appears as slow response tothe deliver operation).
349
350 In other words, the time to process large sets of responses from the provider
351 now depends on the speed of handling the client.
352
353 It is important to remember in developing providers that the Pegasus server
354 can most efficiently process responses if they are passed from the provider
355 to the server individually or in small arrays of objects rather than the
356 provider gathering very large arrays of objects and sending them to the
357 server.
358
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359 karl 1.1.2.2 NEXT GENERATION PROVIDERS
360 KS_TODO
361
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362 karl 1.1.2.1 CONFIGURATION PARAMETERS
363
364 The server includes several configuration parameters to set limits on the
365 processing of pull operations. All of these configuration parameters are
366 compile time parameters rather than runtime.
367
368 1. Maximum value of minimum interoperation time. This parameter defines the
369 maximum time allowed between the return of an open or pull response and
370 the receipt of the next pull or a close operation before the server may
371 close the enumeration. The specification allows the server to set a
372 maximum interoperation time and refuse open requests that with requested
373 operationTimeout greater than that time.
374 CIM_ERR_INVALID_OPERATION_TIMEOUT
375
376 This value is set with the Pegasus environment variable
377 PEGASUS_PULL....
378
379 2. Maximum objects returned in a single open or pull operation. The server
380 can set a maximum limit on the number of objects that can be returned in
381 a single open or pull oepration with the maxObjectCount parameter.
382
383 karl 1.1.2.1 3. Whether the server allows 0 as an interoperation timeout value. The value
384 zero is s special value for the interoperationTimeout in that it tells the
385 server to not timeout any enumeration sequence.
386
387 With this value for interoperationTimeout, the only way to close an
388 enumeration sequence is to complete all of the pulls or issue the close.
389 If for some reason the sequence is not completed, that enumeration context
390 would remain open indefinitly. Since in Pegasus any open enumeration
391 context uses resources (the context object and any provider resposnes that
392 have not yet been issued in a response) it would appear that most
393 platforms would not want to allow the existence of enumeration contexts
394 that cannot be closed by the server.
395
396 4, maximum consecutive pull requests with 0 maxObjectCount. The use of the
397 pull operation with maxObjectCount set to zero could be used to keep an
398 enumeration context open indefinitly (this tells the server to restart the
399 interoperationTimeout but not send any objects in the response). Therefore the
400 specification allows for the server setting maximum limits on this behavior
401 and returning the error CIM_ERR_SERVER_LIMITS_EXCEEDED if this limit is
402 exceeded.
403 Note that this is maximum CONSECUTIVE pulls so that issuing a pull with
404 karl 1.1.2.1 a non-zero count resets this counter.
405
406 KS-TBD - Is this really logical since we can still block by just issuing
407 lots of zero request and an occansional request for one object.
408
409 Pegaus sets the value of this limit to 1000 and allows the implementer to
410 modify it with the PEGASUS_MAXIMUM_ZERO_OBJECTCOUNT environment variable.
411
412 5. Default operationTimeout -
413
414 The default of this parameter is to refuse operat
415
416 In the current release of Pegasus these are all compile time parameters.
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