BIND 10 #2172: Add support for OS X in b10-showtech

[BIND 10 Development]

#2172: Add support for OS X in b10-showtech
-------------------------------------+-------------------------------------
                   Reporter:  jelte  |                 Owner:  jinmei
                       Type:  task   |                Status:  reviewing
                   Priority:         |             Milestone:
  medium                             |  Sprint-20120821
                  Component:         |            Resolution:
  Unclassified                       |             Sensitive:  0
                   Keywords:         |           Sub-Project:  Core
            Defect Severity:  N/A    |  Estimated Difficulty:  0
Feature Depending on Ticket:         |           Total Hours:  0
        Add Hours to Ticket:  3      |
                  Internal?:  0      |
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Comment (by jinmei):

 The revised version basically looks okay.

 I have a few final suggestions.  If you agree on these, please apply
 them and merge; if you don't agree and don't want to include them, I'm
 okay with skipping them at least for this branch, in which case please
 just merge; if you don't agree but want to continue the discussion,
 please do so.

 - `SysInfoOSX` constructor: if setting `_mem_total` fails due to
   exception hw.physmem will be incorrectly used.  I'd reset it to None
   before trying:
 {{{#!python
         self._mem_total = None
         try:
             s = subprocess.check_output(['sysctl', '-n', 'hw.memsize'])
             self._mem_total = int(s.decode('utf-8').strip())
 }}}
 - I don't think it makes sense to include the concept of
   'distro/distribution' for anything other than Linux.  As far as I
   know the concept of 'distribution' is Linux specific, and at the
   very least BSDs don't have that concept.  And, in fact, what we show
   in the 'distribution' row for BSDs is just redundant (platform name
   and version, which is already shown).  As I argued in my previous
   comment, for longer term I think we should remove this concept from
   the top level, but at the moment I propose simply skipping this info
   for BSDs.  I'm attaching a proposed diff for that.

 - totally unrelated to this ticket, but why do we use route(8) to get
   access to routing table for OpenBSD instead of netstat -r?  As far
   as I know the latter works just like in other BSDs, and it'd make
   the implementation and tests simpler if we consistently use netstat.
   I'm attaching a proposed diff for this change.

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Ticket URL: <http://bind10.isc.org/ticket/2172#comment:9>
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