Revision 9a6800e1
| b/lib/cmdlib.py | ||
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HTYPE = None |
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class Tasklet: |
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"""Tasklet base class. |
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Tasklets are subcomponents for LUs. LUs can consist entirely of tasklets or |
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they can mix legacy code with tasklets. Locking needs to be done in the LU, |
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tasklets know nothing about locks. |
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Subclasses must follow these rules: |
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- Implement CheckPrereq |
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- Implement Exec |
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""" |
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def CheckPrereq(self): |
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"""Check prerequisites for this tasklets. |
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This method should check whether the prerequisites for the execution of |
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this tasklet are fulfilled. It can do internode communication, but it |
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should be idempotent - no cluster or system changes are allowed. |
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The method should raise errors.OpPrereqError in case something is not |
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fulfilled. Its return value is ignored. |
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This method should also update all parameters to their canonical form if it |
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hasn't been done before. |
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""" |
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raise NotImplementedError |
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def Exec(self, feedback_fn): |
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"""Execute the tasklet. |
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This method should implement the actual work. It should raise |
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errors.OpExecError for failures that are somewhat dealt with in code, or |
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expected. |
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""" |
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raise NotImplementedError |
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def _GetWantedNodes(lu, nodes): |
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"""Returns list of checked and expanded node names. |
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Also available in: Unified diff