Hi mvo, thanks for this! I think it's a good idea to consolidate the UUID stuff more, however, there are two reasons why I left the connection to app.py (with the signal). The first is because I planned to add an opt-out menu item (which will be a dead-simple change). The second is that I thought it best to keep all of the code that writes to the main config file in one place, that is, in app.py. Else somebody else will have to search if they want to explain where this mysterious other field is coming from in the main config file.

In any case, I am seeing two problems with it the current branch. One is a failure in the unit test, the other occurs when running the app itself (specifically, soemthing that would occur during a first run in a new install, further details below).

First, the unit test:

======================================================================
ERROR: test_mocked_recagent_post_submit_profile (__main__.TestRecommenderAgent)
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Traceback (most recent call last):
  File "test_recagent.py", line 48, in test_mocked_recagent_post_submit_profile
    recommender_agent.post_submit_profile(db)
  File "/home/tremolux/Projects/precise/software-center_review_mvo_recommender_uuid_consolidation/software-center/softwarecenter/backend/recagent.py", line 98, in post_submit_profile
    self.recommender_uuid = get_uuid()
  File "/home/tremolux/Projects/precise/software-center_review_mvo_recommender_uuid_consolidation/software-center/softwarecenter/backend/recagent.py", line 236, in _set_recommender_uuid
    config.set("general", "recommender_uuid", self.recommender_uuid)
  File "/usr/lib/python2.7/ConfigParser.py", line 753, in set
    ConfigParser.set(self, section, option, value)
  File "/usr/lib/python2.7/ConfigParser.py", line 396, in set
    raise NoSectionError(section)
NoSectionError: No section: 'general'

======================================================================
FAIL: test_recagent_recommender_uuid_property (__main__.TestRecommenderAgent)
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Traceback (most recent call last):
  File "test_recagent.py", line 161, in test_recagent_recommender_uuid_property
    self.assertEqual(recommender_agent.recommender_uuid, "foxy-uuid")
AssertionError: '' != 'foxy-uuid'

----------------------------------------------------------------------
Ran 7 tests in 6.296s

FAILED (failures=1, errors=1)

---

And the failure with the app itself occurs in the case where we have not yet made the cfg file (you can see this with a 'rm .config/software-center/softwarecenter.cfg'). This would happen on first run of software-center for a new install, for instance, and if the user opt-in to recommendations then. What happens in the UI is that the "Uploading user profile" spinner hangs.

Traceback (most recent call last):
  File "/home/tremolux/Projects/precise/software-center_review_mvo_recommender_uuid_consolidation/software-center/softwarecenter/ui/gtk3/widgets/recommendations.py", line 127, in _on_opt_in_button_clicked
    self._upload_user_profile_and_get_recommendations()
  File "/home/tremolux/Projects/precise/software-center_review_mvo_recommender_uuid_consolidation/software-center/softwarecenter/ui/gtk3/widgets/recommendations.py", line 131, in _upload_user_profile_and_get_recommendations
    self._upload_user_profile()
  File "/home/tremolux/Projects/precise/software-center_review_mvo_recommender_uuid_consolidation/software-center/softwarecenter/ui/gtk3/widgets/recommendations.py", line 139, in _upload_user_profile
    self.recommender_agent.post_submit_profile(self.catview.db)
  File "/home/tremolux/Projects/precise/software-center_review_mvo_recommender_uuid_consolidation/software-center/softwarecenter/backend/recagent.py", line 98, in post_submit_profile
    self.recommender_uuid = get_uuid()
  File "/home/tremolux/Projects/precise/software-center_review_mvo_recommender_uuid_consolidation/software-center/softwarecenter/backend/recagent.py", line 236, in _set_recommender_uuid
    config.set("general", "recommender_uuid", self.recommender_uuid)
  File "/usr/lib/python2.7/ConfigParser.py", line 753, in set
    ConfigParser.set(self, section, option, value)
  File "/usr/lib/python2.7/ConfigParser.py", line 396, in set
    raise NoSectionError(section)
ConfigParser.NoSectionError: No section: 'general'