Make GenericVNF an abstract class

GenericVNF class is now an abstract class. Only optional methods are
implemented. Mandatory methods:
  - instantiate
  - wait_for_instantiate
  - terminate
  - scale
  - collect_kpi.

JIRA: YARDSTICK-866

Change-Id: Ia8766f9f98816e11894d1e72b0f3bd573d091d99
Signed-off-by: Rodolfo Alonso Hernandez <rodolfo.alonso.hernandez@intel.com>

1 files changed, 40 insertions, 0 deletions

diff --git a/yardstick/common/exceptions.py b/yardstick/common/exceptions.py
index 9c0ec2c19..4780822a4 100644
--- a/yardstick/common/exceptions.py
+++ b/yardstick/common/exceptions.py
@@ -12,8 +12,48 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from oslo_utils import excutils
+
 
 class ProcessExecutionError(RuntimeError):
     def __init__(self, message, returncode):
         super(ProcessExecutionError, self).__init__(message)
         self.returncode = returncode
+
+
+class YardstickException(Exception):
+    """Base Yardstick Exception.
+
+    To correctly use this class, inherit from it and define
+    a 'message' property. That message will get printf'd
+    with the keyword arguments provided to the constructor.
+
+    Based on NeutronException class.
+    """
+    message = "An unknown exception occurred."
+
+    def __init__(self, **kwargs):
+        try:
+            super(YardstickException, self).__init__(self.message % kwargs)
+            self.msg = self.message % kwargs
+        except Exception:  # pylint: disable=broad-except
+            with excutils.save_and_reraise_exception() as ctxt:
+                if not self.use_fatal_exceptions():
+                    ctxt.reraise = False
+                    # at least get the core message out if something happened
+                    super(YardstickException, self).__init__(self.message)
+
+    def __str__(self):
+        return self.msg
+
+    def use_fatal_exceptions(self):
+        """Is the instance using fatal exceptions.
+
+        :returns: Always returns False.
+        """
+        return False
+
+
+class FunctionNotImplemented(YardstickException):
+    message = ('The function "%(function_name)s" is not implemented in '
+               '"%(class_name)" class.')