Enable profilling when env LEAPP_CPROFILE == '1'

Currently on some machines the run of the leapp / snactor is too
slow. Especially framework itself should be fast but sometimes the
time differences are in order of tens seconds. From this point,
it seems useful to be able to start profilling based on the env
variable when it is needed.

leapp/snactor/__init__.py

@@ -2,6 +2,17 @@
 import pkgutil
 import socket
 
+# for profilling
+import cProfile
+import pstats
+try:
+    from StringIO import StringIO
+except ImportError:
+    # TODO: low possibility of the problem with encoding with Python3;
+    # # but it should not be so problematic in this case, so keeping now just
+    # # like that to keep it simple
+    from io import StringIO
+
 from leapp.utils.i18n import _
 from leapp.snactor import commands
 from leapp.snactor.commands import workflow
@@ -68,6 +79,17 @@ def cli(args):
 
 
 def main():
+    profile_enabled = os.environ.get('LEAPP_CPROFILE', '0') == '1'
+    if profile_enabled:
+        pr = cProfile.Profile()
+        pr.enable()
     os.environ['LEAPP_HOSTNAME'] = socket.getfqdn()
     load_commands()
     cli.command.execute(version=_('snactor version {}').format(VERSION))
+    if profile_enabled:
+        pr.disable()
+        s = StringIO.StringIO()
+        sortby = 'cumulative'
+        ps = pstats.Stats(pr, stream=s).sort_stats(sortby)
+        ps.print_stats()
+        print(s.getvalue())