Enable arbitrary numbers of construct layers

src/e3/aws/troposphere/__init__.py

@@ -1,6 +1,8 @@
 from __future__ import annotations
 from abc import ABC, abstractmethod
+from itertools import chain
 from troposphere import AWSObject, Template
+
 from e3.aws import cfn, name_to_id, Session
 from e3.aws.cfn.main import CFNMain
 from e3.aws.troposphere.iam.policy_document import PolicyDocument
@@ -85,6 +87,23 @@ def __init__(
         self.dry_run = dry_run
         self.template = Template()
 
+    def construct_to_objects(self, construct: Construct | AWSObject) -> list[AWSObject]:
+        """Return list of AWS objects resources from a construct.
+
+        :param construct: construct to list resources from
+        """
+        if isinstance(construct, AWSObject):
+            return [construct]
+        else:
+            return list(
+                chain.from_iterable(
+                    [
+                        self.construct_to_objects(el)
+                        for el in construct.resources(stack=self)
+                    ]
+                )
+            )
+
     def add(self, element: Union[AWSObject, Construct, Stack]) -> Stack:
         """Add a Construct or AWSObject to the stack.
 
@@ -103,14 +122,7 @@ def add(self, element: Union[AWSObject, Construct, Stack]) -> Stack:
         # Update the template
         resources = []
         for construct in constructs:
-            if isinstance(construct, Construct):
-                for el in construct.resources(stack=self):
-                    if isinstance(el, Construct):
-                        resources.extend(el.resources(stack=self))
-                    else:
-                        resources.append(el)
-            if isinstance(construct, AWSObject):
-                resources.append(construct)
+            resources.extend(self.construct_to_objects(construct))
         self.template.add_resource(resources)
 
         return self