Issue 4767 - Improve error reporting in update_update_manifests

sitescripts/extensions/utils.py

Index: sitescripts/extensions/utils.py
===================================================================
--- a/sitescripts/extensions/utils.py
+++ b/sitescripts/extensions/utils.py
@@ -26,6 +26,7 @@
 from ConfigParser import SafeConfigParser, NoOptionError
 from StringIO import StringIO
 from sitescripts.utils import get_config
+from xml.parsers.expat import ExpatError
 
 PACKAGE_SUFFIXES = {
     'gecko': '.xpi',
@@ -320,6 +321,10 @@
             if downloadURL is None:
                 raise Exception('No download link found for repo: ' +
                                 repo.repositoryName)
+        except ExpatError:
+            traceback.print_exc()
+            print "Error found while parsing xml from %s link" % repo.repositoryName

[Jon Sonesen, 2017/01/09 07:48:22]

Here you should be using the .format() method for string formatting as per our
style guidelines. Guideline text:

 "Use the + operator when concatenating exactly two strings, use the format()
method for more complex string formatting, use the join() method when
concatenating pre-existing sequences."

[Jon Sonesen, 2017/01/09 08:44:10]

Oops, I also just noticed that you are using double quotes. We are using single
quotes so that string literals match the repr 

[f.nicolaisen, 2017/01/10 08:58:04]

This adds some context (i.e. which repo) to the error, which is good.

However, in the case of the stacktrace shown in the issue, it is a special case
for _getMozillaDownloadLink - meaning that some external service is returning
something we cannot parse:

    ExpatError: mismatched tag: line 6, column 2

I'm guessing that the mozilla service returns something different than we
expect. I would like to know what this is, so that we know more about what
action to take next time it occurs. For example, maybe they return an xml
payload saying <response msg="This service is deprecated, please switch to using
http://blabla.mozilla.org">.

Perhaps it is even possible to test cover this by mocking the external call to
deliver something unexpected like that (ref test_updateManifests.py).

However, I think with these considerations we are going outside the scope of
'infrastructure' and deeper into sitescripts territory. @Vasily/Jon is this
something you want to adopt and roll out in the near future?

+            continue
         except:
             traceback.print_exc()
             continue