Subject: Re: [wsbpel] Issue 190 - BPEL Internal Faults (New Proposed IssueAnnouncement)
1. Isn't this the same issue as the one raised by issue 187 where we ask if there are any constraints in handling of the standard faults? This is proposing a specific resolution where it is recommended that the process always terminates immediately.
2. I tend to side with Danny on this. I don't think we should require that the process terminates immediately always. IMO in at least certain cases this may not be a fatal situation for the whole process (it could be confined to the scope) and other parts of the process may be able to continue by compensating for pertinent. Perhaps the impact could limited to the immediately confining scope and the process could continue, perhaps the area the fault occurred could be non-fatal to whole process (e.g. related look-up rather than modification of any information) or caused by some transient condition that could go away on a retry etc. I think the process (fault handler) should be given a chance to handle the situation rather than terminate always.
3. If we do end-up going the "terminate" always way, we must minimally *not* preclude logging the condition, which could be more intelligent if the faults could be attached some "fault data" (ref issues 187 and 185).
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Hi Danny, BPEL so far does not support any technique for modularizing process authoring, so the situation you describe is a bit out of scope right now. In any case, my view is that the idea that authors of business process are going to be adding code to deal with things like unsupportedReference is just not realistic. I would even argue that those faults don't actually belong at the BP modeling level and need to be dealt with in a different way. Dieter's suggestion allows implementations to manage these situations in the best possible way. This is specially important in the case of long running processes, where months or years of work can be thrown out the window when one of these faults is encountered (the current semantics require the complete unwinding of the execution stack if the fault is not caught and a generic catch all is essentially good for nothing). Typically you want to allow manual intervention to figure out whether the process can be repaired, terminated if not. Paco >From: Danny van der Rijn >To: email@example.com >cc: >Subject: Re: [wsbpel] Issue 190 - BPEL Internal Faults (New Proposed Issue Announcement 02/03/2005 01:47 PM [Resending this with appropriate header to save Tony/Peter the trouble] -1 As I pointed out in our last face to face, this kind of approach will make any kind of modularization extremely difficult. It will give no way for a developer of a piece of BPEL code to protect against the "modelling error" (legacy term: "programming error") of another modeller whose attempt to model the real world failed in a tangible instance. Danny Tony Fletcher wrote: This issue has been added to the wsbpel issue list with a status of "received". The status will be changed to "open" if the TC accepts it as identifying a bug in the spec or decides it should be accepted specially. Otherwise it will be closed without further consideration (but will be marked as "Revisitable") The issues list is posted as a Technical Committee document to the OASIS WSBPEL TC pages on a regular basis. The current edition, as a TC document, is the most recent version of the document entitled in the "Issues" folder of the WSBPEL TC document list - the next posting as a TC document will include this issue. The list editor's working copy, which will normally include an issue when it is announced, is available at this constant URL. Issue 190: BPEL Internal Faults Status: received Date added: 3 Feb 2005 Categories: Fault handling Date submitted: 3 February 2005 Submitter: Dieter Koenig1 Document: WS-BPEL Working Draft, December, 2004 Related Issues: Issue 163 : languageExecutionFault, Issue 169 : Transition condition error handling clarification, and Issue 187 : Legality of Explicitly throwing or rethrowing Standard faults. Description: There are a number of cases in the current spec where the behavior of a process is described as *undefined*, in particular, after recognizing internal errors described as standard faults. With the exception of "bpel:joinFailure", *all* of these situations represent modelling errors that cannot be dealt with by the business process itself in a meaningful way. This behavior becomes even more questionable for catchAll handlers that try to deal with multiple application faults and unexpectedly encounter a standard fault. Submitter's proposal: Instead of allowing processes to catch these as standard faults, we propose that the process instance must *terminate* immediately when such a situation is encountered. The behavior of terminate is well-defined in BPEL -- as far as BPEL is concerned the instance execution ends when terminate is encountered without any fault handling behavior. Any additional facilities for extended support for, e.g., repair and continue, is definitely out of scope. This approach would also create a clear direction for dealing with any pathological situation within an inlined language (Issue 163) and therefore also for errors within transition conditions (Issue 169). Changes: 3 Feb 2005 - new issue Best Regards, Tony