add globals to model and able to resolve it

pycfmodel/model/cf_model.py

@@ -18,9 +18,10 @@ class CFModel(CustomModel):
 
     Properties:
 
-    - AWSTemplateFormatVersion
+    - AWSTemplateFormatVersion: The AWS CloudFormation template version that the template conforms to.
     - Conditions: Conditions that control behaviour of the template.
     - Description: Description for the template.
+    - Globals: TODO
     - Mappings: A 3 level mapping of keys and associated values.
     - Metadata: Additional information about the template.
     - Outputs: Output values of the template.
@@ -30,11 +31,14 @@ class CFModel(CustomModel):
     - Transform: For serverless applications, specifies the version of the AWS Serverless Application Model (AWS SAM) to use.
 
     More info at [AWS Docs](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/template-anatomy.html)
+
+    More info for Globals at [AWS Globals Docs](https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/sam-specification-template-anatomy-globals.html)
     """
 
     AWSTemplateFormatVersion: Optional[date]
     Conditions: Optional[Dict] = {}
     Description: Optional[str] = None
+    Globals: Optional[Dict] = {}
     Mappings: Optional[Dict[str, Dict[str, Dict[str, Any]]]] = {}
     Metadata: Optional[Dict[str, Any]] = None
     Outputs: Optional[Dict[str, Dict[str, Union[str, Dict]]]] = {}
@@ -84,14 +88,23 @@ def resolve(self, extra_params=None) -> "CFModel":
                 {key: _extended_bool(resolve(value, extended_parameters, self.Mappings, resolved_conditions))}
             )
 
+        globals_cf = dict_value.pop("Globals", {})
+        resolved_globals = {
+            key: resolve(value, extended_parameters, self.Mappings, resolved_conditions)
+            for key, value in globals_cf.items()
+        }
+
         resources = dict_value.pop("Resources")
         resolved_resources = {
             key: resolve(value, extended_parameters, self.Mappings, resolved_conditions)
             for key, value in resources.items()
             if value.get("Condition") is None
             or (value.get("Condition") is not None and resolved_conditions.get(value["Condition"], True))
         }
-        return CFModel(**dict_value, Conditions=resolved_conditions, Resources=resolved_resources)
+
+        return CFModel(
+            **dict_value, Conditions=resolved_conditions, Resources=resolved_resources, Globals=resolved_globals
+        )
 
     def expand_actions(self) -> "CFModel":
         """
@@ -134,3 +147,11 @@ def resources_filtered_by_type(
             if isinstance(resource, allowed_resource_classes) or resource.Type in allowed_types:
                 result[resource_name] = resource
         return result
+
+    def is_sam_model(self) -> bool:
+        transform = self.Transform
+        if self.Transform is None:
+            return False
+        if isinstance(transform, str):
+            transform = [transform]
+        return any(macro.startswith("AWS::Serverless") for macro in transform)

tests/test_cf_model.py

@@ -18,6 +18,55 @@ def model():
             "Resources": {"Logical ID": {"Type": "Resource type", "Properties": {"foo": "bar"}}},
             "Rules": {},
             "Outputs": {},
+            "Globals": {},
+        }
+    )
+
+
+@pytest.fixture()
+def model_single_transform():
+    return CFModel(
+        **{
+            "AWSTemplateFormatVersion": "2012-12-12",
+            "Description": "",
+            "Metadata": {},
+            "Parameters": {},
+            "Mappings": {},
+            "Conditions": {},
+            "Transform": "AWS::Serverless-2016-10-31",
+            "Resources": {"Logical ID": {"Type": "Resource type", "Properties": {"foo": "bar"}}},
+            "Rules": {},
+            "Outputs": {},
+        }
+    )
+
+
+@pytest.fixture()
+def model_no_transform():
+    return CFModel(
+        **{
+            "AWSTemplateFormatVersion": "2012-12-12",
+            "Description": "",
+            "Metadata": {},
+            "Parameters": {},
+            "Mappings": {},
+            "Conditions": {},
+            "Resources": {"Logical ID": {"Type": "Resource type", "Properties": {"foo": "bar"}}},
+            "Rules": {},
+            "Outputs": {},
+        }
+    )
+
+
+@pytest.fixture()
+def model_with_empty_globals():
+    return CFModel(
+        **{
+            "AWSTemplateFormatVersion": "2012-12-12",
+            "Globals": {},
+            "Parameters": {},
+            "Transform": "AWS::Serverless-2016-10-31",
+            "Resources": {"Logical ID": {"Type": "AWS::Dummy::Dummy", "Properties": {"foo": "bar"}}},
         }
     )
 
@@ -26,6 +75,7 @@ def test_basic_json(model: CFModel):
     assert type(model).__name__ == "CFModel"
     assert len(model.Resources) == 1
     assert model.Transform == ["MyMacro", "AWS::Serverless"]
+    assert model.Globals == {}
 
 
 def test_resources_filtered_by_type():
@@ -61,3 +111,15 @@ def test_transform_handles_string():
 
 def test_resolve_model(model):
     assert model.resolve() == model
+
+
+@pytest.mark.parametrize(
+    "model_fixture,is_sam_model",
+    [("model", True), ("model_single_transform", True), ("model_no_transform", False)],
+)
+def test_transform_is_of_type_sam_model(model_fixture, is_sam_model, request):
+    assert request.getfixturevalue(model_fixture).is_sam_model() is is_sam_model
+
+
+def test_model_with_empty_globals_is_able_to_resolve_to_empty_dict(model_with_empty_globals):
+    assert model_with_empty_globals.Globals == {}

tests/test_resolver.py

@@ -815,3 +815,25 @@ def test_resolve_find_in_map_for_bool_values_in_map(params, expected_resolved_va
 
     result = resolve_find_in_map(function_body=function_body, params=params, mappings=mappings, conditions={})
     assert result == expected_resolved_value
+
+
+def test_resolve_globals_with_values_and_referencing_parameters():
+    """
+    This test aims to be able to solve these type of templates:
+    https://github.com/Skyscanner/cfripper/issues/259#issuecomment-1824485673
+    """
+    template = {
+        "AWSTemplateFormatVersion": "2012-12-12",
+        "Transform": "AWS::Serverless-2016-10-31",
+        "Parameters": {
+            "ProjectName": {"Type": "String", "Default": "my-project"},
+            "Environment": {"Type": "String", "Default": "development"},
+        },
+        "Globals": {"Function": {"Tags": {"Env": {"Ref": "Environment"}, "Project": {"Ref": "ProjectName"}}}},
+        "Resources": {"MySNSTopic": {"Type": "AWS::SNS::Topic"}},
+    }
+
+    model = parse(template).resolve()
+
+    assert model.Globals.get("Function").get("Tags").get("Env") == "development"
+    assert model.Globals.get("Function").get("Tags").get("Project") == "my-project"