launchpad-reviewers team mailing list archive

[Aaron Bentley <aaron@xxxxxxxxxxxxx>]

Aaron Bentley has proposed merging lp:~abentley/launchpad/detect-xen-2 into lp:launchpad.

Requested reviews:
  Launchpad code reviewers (launchpad-reviewers)


= Summary =
Detect that running as a Xen guest

== Proposed fix ==
It turns out xen-detect doesn't detect whether the current environment is a Xen
guest, so Lamont said that ensuring /proc/xen but not /prox/xen/xsd_kva exists
was a hacky, but workable test.

== Pre-implementation notes ==
Done at Lamont's request

== Implementation details ==
See above

== Tests ==
None

== Demo and Q/A ==
Get Lamont to install this on the staging buildfarm.  Ensure it can perform a
sourcepackagerecipe build.


= Launchpad lint =

Checking for conflicts and issues in changed files.

Linting changed files:
  lib/canonical/buildd/buildrecipe
-- 
https://code.launchpad.net/~abentley/launchpad/detect-xen-2/+merge/39294
Your team Launchpad code reviewers is requested to review the proposed merge of lp:~abentley/launchpad/detect-xen-2 into lp:launchpad.

=== modified file 'lib/canonical/buildd/buildrecipe'
--- lib/canonical/buildd/buildrecipe	2010-09-30 20:22:15 +0000
+++ lib/canonical/buildd/buildrecipe	2010-10-25 16:59:49 +0000
@@ -7,12 +7,11 @@
 __metaclass__ = type
 
 
-import errno
 import os
+import os.path
 import pwd
-import re
 import socket
-from subprocess import call, Popen, PIPE
+from subprocess import call
 import sys
 
 
@@ -26,21 +25,8 @@
 class NotVirtualized(Exception):
     """Exception raised when not running in a virtualized environment."""
 
-
-class NoXenDetect(NotVirtualized):
-    """xen-detect not installed."""
-
     def __init__(self):
-        NotVirtualized.__init__(self, 'xen-detect is not installed.')
-
-
-class BadXenDetect(NotVirtualized):
-    """xen-detect's output not not indicate that we are virtualized."""
-
-    def __init__(self, xen_detect_output):
-        NotVirtualized.__init__(
-            self, 'Bad xen-detect output: %s' % xen_detect_output)
-        self.xen_detect_output = xen_detect_output
+        Exception.__init__(self, 'Not running under Xen.')
 
 
 class RecipeBuilder:
@@ -191,18 +177,10 @@
 def ensure_virtualized():
     """Raise an exception if not running in a virtualized environment.
 
-    Raises if unsure, or if not running under Xen.
+    Raises if not running under Xen.
     """
-    try:
-        proc = Popen(['xen-detect'], stdout=PIPE)
-    except OSError, e:
-        if e.errno != errno.ENOENT:
-            raise
-        raise NoXenDetect()
-    status_code = proc.wait()
-    output = proc.stdout.read()
-    if not re.match('Running in .* context on Xen', output):
-        raise BadXenDetect(output)
+    if not os.path.isdir('/proc/xen') or os.path.exists('/proc/xen/xsd_kva'):
+        raise NotVirtualized()
 
 
 if __name__ == '__main__':