Add multiple executor and whitelist support to build manager

buildman/manager/executor.py

@@ -61,6 +61,20 @@ class BuilderExecutor(object):
     """
     raise NotImplementedError
 
+  def allowed_for_namespace(self, namespace):
+    """ Returns true if this executor can be used for builds in the given namespace. """
+    namespace_whitelist = self.executor_config.get('NAMESPACE_WHITELIST')
+    if namespace_whitelist is not None:
+      return namespace in namespace_whitelist
+
+    return True
+
+  @property
+  def minimum_retry_threshold(self):
+    """ Returns the minimum number of retries required for this executor to be used or 0 if
+        none. """
+    return self.executor_config.get('MINIMUM_RETRY_THRESHOLD', 0)
+
   def generate_cloud_config(self, realm, token, coreos_channel, manager_hostname,
                             quay_username=None, quay_password=None):
     if quay_username is None: