Merge lp:~nuclearbob/utah/installclient-improvement into lp:utah

[Max Brustkern]

Sometimes when I provision a machine and install the client, some other apt or dpkg process is running, and I can't get a lock on the dpkg database. This causes the whole installation to fail.

I've added to the command that installs the client so that it will wait until it can get a lock before trying to install the package. It seemed to work fine on a VMToolsVM. I plan to test it on a CustomVM as well, and a CobblerMachine certainly wouldn't hurt. Since both of those use run from SSHMachine, I think if it works on one it should work on the other.

The problem I'm having with testing right now is that the client install is broken since it PreDepends on python-pip, and that's not getting installed by the preseed yet. I can commit a fix for that, but I think we're redoing that anyway, so I might just wait until that's ready.

[Joe Talbott (joetalbott)]

Looks okay to me. I think there might be a small race condition between when the while
tests the lock and the dpkg -i runs in which another process could obtain the lock. However
it's such a small window.

review: Approve

[Javier Collado (javier.collado)]

This is probably the update manager being launchpad automatically. What about trying to disable automatic updates like this:

gconftool --set --type bool /apps/update-notifier/auto_launch false

I'm not sure how to best translate this to the preseed (maybe just as a late command), but I think it's worth giving a try.

[Javier Collado (javier.collado)]

One more thing I'd like to comment is that to concatenate two strings you don't really need any operator (they are still needed to concatenate the output from a function like os.path.join though), just put them together:
>>> 'Hello' ' ' 'World'
'Hello World'
>>>

In my opinion, when there are less plus signs, the code is more readable.

[Max Brustkern (nuclearbob)]

Good point on the plus signs. I'll try to remember to do that in the future.

=== modified file 'utah/provisioning/provisioning.py'
--- utah/provisioning/provisioning.py	2012-08-08 23:49:34 +0000
+++ utah/provisioning/provisioning.py	2012-08-09 19:18:23 +0000
@@ -232,8 +232,11 @@
                 raise err
             except AttributeError:
                 raise err
-        if self.run('DEBIAN_FRONTEND=noninteractive dpkg -i '
-                 + os.path.join(tmppath, os.path.split(self.getclientdeb())[1])
+        if self.run('export DEBIAN_FRONTEND=noninteractive ; while '
+                 + '(fuser /var/lib/dpkg/lock >/dev/null 2>&1) ; do echo '
+                 + '"Waiting for dpkg lock to become available" ; sleep 10 ; '
+                 + 'done ; dpkg -i ' + os.path.join(tmppath,
+                 os.path.split(self.getclientdeb())[1])
                  + ' || apt-get -y -f install', root=True) != 0:
             raise UTAHProvisioningException('Failed to install client')