Merge lp:~johnsca/charm-helpers/cmdline-conditional-import into lp:charm-helpers

[Cory Johns]

Conditional import of cmdline in hookenv so that we can still avoid duplication while gracefully dealing with charms that partially sync charmhelpers directly in (sans the cli portion).

[Charles Butler (lazypower)]

+1 LGTM - expressing this into upstream as it broke OpenStack CI - if this causes an issue lets bug it and circle back.

move along, this is not the droid you are looking for.

review: Approve

=== modified file 'charmhelpers/core/hookenv.py'
--- charmhelpers/core/hookenv.py	2015-07-29 15:33:35 +0000
+++ charmhelpers/core/hookenv.py	2015-07-31 19:46:11 +0000
@@ -34,7 +34,22 @@
 import tempfile
 from subprocess import CalledProcessError
 
-from charmhelpers.cli import cmdline
+try:
+    from charmhelpers.cli import cmdline
+except ImportError as e:
+    # due to the anti-pattern of partially synching charmhelpers directly
+    # into charms, it's possible that charmhelpers.cli is not available;
+    # if that's the case, they don't really care about using the cli anyway,
+    # so mock it out
+    if str(e) == 'No module named cli':
+        class cmdline(object):
+            @classmethod
+            def subcommand(cls, *args, **kwargs):
+                def _wrap(func):
+                    return func
+                return _wrap
+    else:
+        raise
 
 import six
 if not six.PY3: