Runlist file not checked before downloading ISO

[Javier Collado]

Trying to reproduce bug1012860 using the following command:
sudo -i -u utah /usr/share/utah/examples/run_utah_tests.py -d -s precise -t server -a i386 /usr/share/utah/examples/master.run 'http://people.canonical.com/~max/max_test.run'

I got the following traceback:
  File "/usr/lib/python2.7/urllib.py", line 476, in open_local_file
    raise IOError(e.errno, e.strerror, e.filename)
IOError: [Errno 2] No such file or directory: '/usr/share/utah/examples/master.run'

Looks like that master.run is no longer located under /usr/share/utah/examples/, but /usr/share/utah/client/examples/. That's fine, but the problem is that that error was printer after downloading the ISO (and that took quite a long time). Since the file name is passed as an argument in the command line, it would be better to check if the file exists before downloading the ISO to get faster feedback of the mistake.

In the case of URLs, that might not be so important, but anyway at least an attempt to make sure that URL is valid would be nice as well.

[Max Brustkern (nuclearbob)]

I think validation of the runlist files is definitely worth implementing. As far as the files that are potentially downloaded by the install process, I just committed a revision to reorder those by expected size. Now, we go preseed, xml, kernel, initrd, image, which gives the smallest downloads the first opportunity to fail. If we want to validate all URL's before actually downloading, that could be done as well, but this should speed up failures until then.

[Javier Collado (javier.collado)]

Just for the record, the change with the downloads reorder can be found in:
lp:utah/dev rev. 358 (0.3ubuntu393 in debian/changelog)