Failures in disk.py Filesystem.create()

[Bernie Bernstein]

When building a vm as a xen image (for EC2 deployment), building fails when trying to create the root filesystem:

  File "/usr/bin/vmbuilder", line 24, in <module>
    cli.main()
  File "/usr/lib/python2.6/dist-packages/VMBuilder/contrib/cli.py", line 116, in main
    hypervisor.install_os()
  File "/usr/lib/python2.6/dist-packages/VMBuilder/hypervisor.py", line 64, in install_os
    self.call_hooks('mount_partitions', self.chroot_dir)
  File "/usr/lib/python2.6/dist-packages/VMBuilder/distro.py", line 66, in call_hooks
    call_hooks(self, *args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/VMBuilder/util.py", line 165, in call_hooks
    getattr(context, func, log_no_such_method)(*args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/VMBuilder/hypervisor.py", line 82, in mount_partitions
    fs.create()
  File "/usr/lib/python2.6/dist-packages/VMBuilder/disk.py", line 332, in create
    if not os.path.exists(self.filename):
  File "/usr/lib/python2.6/genericpath.py", line 18, in exists
    st = os.stat(path)
TypeError: coercing to Unicode: need string or buffer, NoneType found

This seems to occur whenever a Filesystem instance is created with None as the filename (the default).

After fixing this issue with an additional check, the following exception occurs:

  File "/usr/bin/vmbuilder", line 24, in <module>
    cli.main()
  File "/usr/lib/python2.6/dist-packages/VMBuilder/contrib/cli.py", line 116, in main
    hypervisor.install_os()
  File "/usr/lib/python2.6/dist-packages/VMBuilder/hypervisor.py", line 64, in install_os
    self.call_hooks('mount_partitions', self.chroot_dir)
  File "/usr/lib/python2.6/dist-packages/VMBuilder/distro.py", line 66, in call_hooks
    call_hooks(self, *args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/VMBuilder/util.py", line 165, in call_hooks
    getattr(context, func, log_no_such_method)(*args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/VMBuilder/hypervisor.py", line 82, in mount_partitions
    fs.create()
  File "/usr/lib/python2.6/dist-packages/VMBuilder/disk.py", line 345, in create
    self.filename = '%s/%s' % (self.vm.workdir, self.filename)
AttributeError: 'Xen' object has no attribute 'workdir'

[Bernie Bernstein (bernie9998)]

I have investigated further and came to the real cause of the problem. Apparently the CLI class will provide a filename when creating disks and filesystems with util.tmpfile. However, it fails to do so when allocating filesystems when preferred_storage is set to STORAGE_FS_IMAGE and when a partitiions file is provided.

As a result, when using a plugin (such as XEN) which uses STORAGE_FS_IMAGE and filesystems are specified with a partitions file rather than specifying them in the arguments, the result is a failure due to the Filesystem object being unable to create its own filename.

I have fixed this issue by creating temp files for this case in the same manner as is done for all other cases.

I would also suggest changing the Filesystem class to make filename a required parameter similar that of Disk and removing the the logic that attempts to create one if not provided, since such logic relies on a workdir attribute that does not appear to ever be set.

[Bernie Bernstein (bernie9998)]

As per suggestion, including a patch to remove generating filename from Filesystem and instead raise a VMBuilderException if it is not provided (similar behavior as Disk).

This patch assumes the first patch, 'Patch to prevent calling os.path.exists if the filename is None' is not applied.