BIND 10 #2853: Python wrapper of data source extensions

[BIND 10 Development]

#2853: Python wrapper of data source extensions
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            Reporter:  jinmei        |                        Owner:
                Type:  task          |  vorner
            Priority:  medium        |                       Status:
           Component:  data source   |  reviewing
            Keywords:                |                    Milestone:
           Sensitive:  0             |  Sprint-20130625
         Sub-Project:  DNS           |                   Resolution:
Estimated Difficulty:  5             |                 CVSS Scoring:
         Total Hours:  0             |              Defect Severity:  N/A
                                     |  Feature Depending on Ticket:
                                     |  shared memory data source
                                     |          Add Hours to Ticket:  0
                                     |                    Internal?:  0
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Comment (by jinmei):

 Replying to [comment:22 muks]:

 > Replying to [comment:21 jinmei]:
 > > This seems to be problematic:
 > >
 > > {{{#!cpp
 > >             PyObject *tup = Py_BuildValue("(ssI)",
 > >                                           status[i].getName().c_str(),
 > >
 status[i].getSegmentType().c_str(),
 > >
 status[i].getSegmentState());
 > > }}}
 > >
 > > because if the state is unused, getSegmentType() throws.
 >
 > I have added code to handle this exception, and also updated the C++
 > `getStatus()` implementation to be more correct (#2943 should be a
 > duplicate now).  However, from the Python code I can't find a way to
 > trigger that exception to test it.

 Regarding the test: if you meant how to test the case of unused state,
 you should simply use a data source with disabling in-memory cache.

 Regarding the code, I personally think it's better to check the state
 explicitly and use Py_None if it's SEGMENT_UNUSED.

 And, not directly on this point, but on a closer look the code looks
 generally unsafe.  For example, in `ConfigurableClientList_getStatus`
 if this fails:

 {{{#!cpp
             PyObject* tup = Py_BuildValue("(sOI)",
                                           status[i].getName().c_str(),
                                           segment_type,
                                           status[i].getSegmentState());
 }}}

 then the reference to segment_type will be lost.  You'll need a help
 of `PyObjectContainer` here.

-- 
Ticket URL: <http://bind10.isc.org/ticket/2853#comment:24>
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