Merge lp:~pwlars/ubuntu-ci-services-itself/image-build-error-report into lp:ubuntu-ci-services-itself

[Paul Larson]

Improve failure completion message from imagebuilder to include the command that failed

This is a really basic fix for https://bugs.launchpad.net/ubuntu-ci-services-itself/+bug/1284672 but I have some other stuff in the works to provide a log artifact in swift at the end with detailed logs. This will still be useful even with the other patch though, as the user will need to link to that artifact to get the full logs, but this will give the failing command, providing more insight into what went wrong. Example output when this is enabled:
04:38:59 INFO PROGRESS_TRIGGER: STATUS: {u'message': u'Adding requested packages to the image...'}
04:39:22 INFO PROGRESS_TRIGGER: COMPLETED: {u'message': u"CalledProcessError: Command '['chroot', '/tmp/tmpQ0D6qb/mountpoint', '/usr/bin/apt-get', 'update']' returned non-zero exit status 100", u'exit': True, u'result': u'FAILED'}

[PS Jenkins bot (ps-jenkins)]

PASSED: Continuous integration, rev:277
http://s-jenkins.ubuntu-ci:8080/job/uci-engine-ci/235/
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review: Approve (continuous-integration)

[Paul Larson (pwlars)]

This can be superceded by https://code.launchpad.net/~pwlars/ubuntu-ci-services-itself/imagebuild-better-logging/+merge/208376

Unmerged revisions

277. By Paul Larson on 2014-02-26

Return the exception details in the failure status

Fixes LP:1284672

=== modified file 'image-builder/run_worker'
--- image-builder/run_worker	2014-02-22 16:22:26 +0000
+++ image-builder/run_worker	2014-02-26 04:47:54 +0000
@@ -51,9 +51,11 @@
         if amqp_utils.progress_completed(trigger, {'image_id': image_id}):
             log.error(
                 'Unable to notify progress-trigger completition of action')
-    except Exception as e:
-        type, val, tb = sys.exc_info()
-        amqp_utils.progress_failed(trigger, {'message': val.message})
+    except Exception:
+        exc_type, val, tb = sys.exc_info()
+        exc_name = type(exc_type).__class__.__name__
+        amqp_utils.progress_failed(
+            trigger, {'message': '%s: %s' % (exc_name, val)})
         log.exception('Image build failed:')
 
     finally: