Add new methods for immediate revert and checking if pending commit c…

…onfirms exist (#628)

napalm/base/base.py

@@ -188,16 +188,22 @@ def commit_confirm(self):
         """Confirm pending commit."""
         raise NotImplementedError
 
-    def discard_config(self):
+    def commit_confirm_revert(self):
+        """Abort pending commit confirm immediately and rollback to previous state"""
+        raise NotImplementedError
+
+    def has_pending_commit(self):
         """
-        Discards the configuration loaded into the candidate.
+        :return A boolean indicating whether any pending commit confirms exist.
         """
         raise NotImplementedError
 
+    def discard_config(self):
+        """Discards the configuration loaded into the candidate."""
+        raise NotImplementedError
+
     def rollback(self):
-        """
-        If changes were made, revert changes to the original state.
-        """
+        """If changes were made, revert changes to the original state."""
         raise NotImplementedError
 
     def get_facts(self):

napalm/ios/ios.py

@@ -425,11 +425,20 @@ def commit_confirm(self):
         cmd = "configure confirm"
         self.device.send_command_expect(cmd)
 
-    def _commit_abort(self):
+    def commit_confirm_revert(self):
         """Immediately revert pending commit confirm."""
         cmd = "configure revert now"
         self.device.send_command_expect(cmd)
 
+    def has_pending_commit(self):
+        """
+        :return A boolean indicating whether any pending commit confirms exist.
+        """
+        cmd = "show archive config rollback timer"
+        search_pattern = r"No Rollback Confirmed Change pending"
+        output = self.device.send_command_expect(cmd)
+        return not bool(re.search(search_pattern, output, flags=re.I))
+
     def commit_config(self, confirmed=None, message=None):
         """If replacement operation, perform 'configure replace' for the entire config.