avocado.plugins: Check and log when loading plugins behaves bad.

Signed-off-by: NRuda Moura <rmoura@redhat.com>

avocado/plugins/builtin.py

@@ -14,8 +14,11 @@
 
 """Builtin plugins."""
 
+import logging
 from importlib import import_module
 
+log = logging.getLogger("avocado.plugins")
+
 __all__ = ['load_builtins']
 
 Builtins = [('avocado.plugins.runner', 'TestLister'),
@@ -33,7 +36,11 @@ def load_builtins(set_globals=True):
     for module, klass in Builtins:
         try:
             plugin_mod = import_module(module)
-        except ImportError:
+        except ImportError as err:
+            log.error("Could not import pluging '': %s", klass, err)
+            continue
+        except SyntaxError as err:
+            log.error("Plugin '%s' with syntax error: %s", klass, err)
             continue
         if hasattr(plugin_mod, klass):
             plugin = getattr(plugin_mod, klass)

avocado/plugins/manager.py

@@ -53,7 +53,11 @@ class PluginManager(object):
     def activate(self, app_args):
         for plugin in self.plugins:
             if plugin.configured:
-                plugin.activate(app_args)
+                try:
+                    plugin.activate(app_args)
+                except Exception as err:
+                    log.error("Could not activate plugin '%s': %s",
+                              plugin.name, err)
 
 
 class BuiltinPluginManager(PluginManager):