Improve error reporting in update_update_manifests

[ferris]

Environment

update1

How to reproduce

Theory: Run the update_update_manifests sitescript while overriding the remote URL ​https://services.addons.mozilla.org/en-US/firefox/api/1/addon/adblock-plus to respond with an error

Observed behaviour

Receiving these cron error mails a few times every month:

Title: Cron <sitescripts@update1> /usr/local/bin/update_update_manifests

Traceback (most recent call last):
  File "/opt/sitescripts/sitescripts/extensions/utils.py", line 319, in getDownloadLinks
    (downloadURL, version) = _getDownloadLink(repo)
  File "/opt/sitescripts/sitescripts/extensions/utils.py", line 295, in _getDownloadLink
    return _getMozillaDownloadLink(repo.galleryID)
  File "/opt/sitescripts/sitescripts/extensions/utils.py", line 263, in _getMozillaDownloadLink
    document = dom.parse(_urlopen(url))
  File "/usr/lib/python2.7/xml/dom/minidom.py", line 1920, in parse
    return expatbuilder.parse(file)
  File "/usr/lib/python2.7/xml/dom/expatbuilder.py", line 928, in parse
    result = builder.parseFile(file)
  File "/usr/lib/python2.7/xml/dom/expatbuilder.py", line 207, in parseFile
    parser.Parse(buffer, 0)
ExpatError: mismatched tag: line 6, column 2

Expected behaviour

More information on which URL responded with what error and a suggested action to take (i.e. make sure that the remote service is up, still exists, etc).

[jsonesen]

Hey guys,

Is it alright if you CC myself, Vasily, or Sebastian when making tickets in relation to the sitescripts module? For reference you can see who should be CC'd and added to reviews in the ​modules section of the adblockplus.org website. This is helpful so that we can discuss the implementation and document it here prior to actually making the review or merging code. This way reviewing is streamlined and does not have to include as much of the implementation discussion.

[abpbot]

A commit referencing this issue has landed:
​Issue 4767 - Improve error reporting in update_update_manifests...

[sebastian]

Please assign issues to yourself when you are working on them.