Merge lp:~thedac/charm-helpers/lp1691881 into lp:charm-helpers

[David Ames]

Decode subprocess output for python3 in ipv6 check

When using python3, the code encounters errors related to type mismatch.
subprocess requires an extra decode of return values to address this.

Partial-Bug: #1691881

[Chris MacNaughton (chris.macnaughton)]

Looks good to me

review: Approve

[Alex Kavanagh (ajkavanagh)]

Won't this generate a u"" on Python 2? In which case, that's a change in behaviour for Python 2, as subprocess.check_output(...) returns a str rather than a unicode.

I reckon a check should be done with six.PY3 and only perform the decode(...) in that situation.

review: Needs Fixing

[lp:~thedac/charm-helpers/lp1691881]

749. By David Ames on 2017-06-01

Only perform UTF-8 decode if python3

[Alex Kavanagh (ajkavanagh)]

LGTM - thanks for making the change.

review: Approve

=== modified file 'charmhelpers/contrib/network/ip.py'
--- charmhelpers/contrib/network/ip.py	2017-04-25 17:13:19 +0000
+++ charmhelpers/contrib/network/ip.py	2017-06-01 15:53:15 +0000
@@ -244,9 +244,11 @@
         result = subprocess.check_output(
             ['sysctl', 'net.ipv6.conf.all.disable_ipv6'],
             stderr=subprocess.STDOUT)
-        return "net.ipv6.conf.all.disable_ipv6 = 1" in result
     except subprocess.CalledProcessError:
         return True
+    if six.PY3:
+        result = result.decode('UTF-8')
+    return "net.ipv6.conf.all.disable_ipv6 = 1" in result
 
 
 def get_iface_addr(iface='eth0', inet_type='AF_INET', inc_aliases=False,