Implement update stack

simonrw · simonrw · commit 486bb1d198fc · 2025-06-20T22:40:47.000+01:00
diff --git a/localstack-core/localstack/services/cloudformation/v2/provider.py b/localstack-core/localstack/services/cloudformation/v2/provider.py
@@ -36,11 +36,14 @@
     StackName,
     StackNameOrId,
     StackStatus,
+    UpdateStackInput,
+    UpdateStackOutput,
 )
 from localstack.services.cloudformation import api_utils
 from localstack.services.cloudformation.engine import template_preparer
 from localstack.services.cloudformation.engine.v2.change_set_model import (
     ChangeSetModel,
+    ChangeType,
     NodeTemplate,
 )
 from localstack.services.cloudformation.engine.v2.change_set_model_describer import (
@@ -562,6 +565,112 @@ def describe_stack_events(
             raise StackNotFoundError(stack_name)
         return DescribeStackEventsOutput(StackEvents=stack.events)
 
+    @handler("UpdateStack", expand=False)
+    def update_stack(
+        self,
+        context: RequestContext,
+        request: UpdateStackInput,
+    ) -> UpdateStackOutput:
+        try:
+            stack_name = request["StackName"]
+        except KeyError:
+            # TODO: proper exception
+            raise ValidationError("StackName must be specified")
+        state = get_cloudformation_store(context.account_id, context.region)
+        template_body = request.get("TemplateBody")
+        # s3 or secretsmanager url
+        template_url = request.get("TemplateURL")
+
+        # validate and resolve template
+        if template_body and template_url:
+            raise ValidationError(
+                "Specify exactly one of 'TemplateBody' or 'TemplateUrl'"
+            )  # TODO: check proper message
+
+        if not template_body and not template_url:
+            raise ValidationError(
+                "Specify exactly one of 'TemplateBody' or 'TemplateUrl'"
+            )  # TODO: check proper message
+
+        template_body = api_utils.extract_template_body(request)
+        structured_template = template_preparer.parse_template(template_body)
+
+        # this is intentionally not in a util yet. Let's first see how the different operations deal with these before generalizing
+        # handle ARN stack_name here (not valid for initial CREATE, since stack doesn't exist yet)
+        stack: Stack
+        if is_stack_arn(stack_name):
+            stack = state.stacks_v2.get(stack_name)
+            if not stack:
+                raise ValidationError(f"Stack '{stack_name}' does not exist.")
+
+        else:
+            # stack name specified, so fetch the stack by name
+            stack_candidates: list[Stack] = [
+                s for stack_arn, s in state.stacks_v2.items() if s.stack_name == stack_name
+            ]
+            active_stack_candidates = [
+                s for s in stack_candidates if self._stack_status_is_active(s.status)
+            ]
+
+            if not active_stack_candidates:
+                raise ValidationError(f"Stack '{stack_name}' does not exist.")
+            elif len(active_stack_candidates) > 1:
+                raise RuntimeError("Multiple stacks matched, update matching logic")
+            stack = active_stack_candidates[0]
+
+        # TODO: proper status modeling
+        before_parameters = stack.resolved_parameters
+        # TODO: reconsider the way parameters are modelled in the update graph process.
+        #  The options might be reduce to using the current style, or passing the extra information
+        #  as a metadata object. The choice should be made considering when the extra information
+        #  is needed for the update graph building, or only looked up in downstream tasks (metadata).
+        request_parameters = request.get("Parameters", list())
+        # TODO: handle parameter defaults and resolution
+        after_parameters: dict[str, Any] = {
+            parameter["ParameterKey"]: parameter["ParameterValue"]
+            for parameter in request_parameters
+        }
+        before_template = stack.template
+        after_template = structured_template
+
+        change_set = ChangeSet(
+            stack,
+            {"ChangeSetName": f"cs-{stack_name}-create", "ChangeSetType": ChangeSetType.CREATE},
+            template=after_template,
+        )
+        self._setup_change_set_model(
+            change_set=change_set,
+            before_template=before_template,
+            after_template=after_template,
+            before_parameters=before_parameters,
+            after_parameters=after_parameters,
+        )
+
+        if change_set.update_model.change_type == ChangeType.UNCHANGED:
+            raise ValidationError("No updates are to be performed.")
+
+        stack.set_stack_status(StackStatus.UPDATE_IN_PROGRESS)
+        change_set_executor = ChangeSetModelExecutor(change_set)
+
+        def _run(*args):
+            try:
+                result = change_set_executor.execute()
+                stack.set_stack_status(StackStatus.UPDATE_COMPLETE)
+                stack.resolved_resources = result.resources
+                stack.resolved_parameters = result.parameters
+                stack.resolved_outputs = result.outputs
+                # if the deployment succeeded, update the stack's template representation to that
+                # which was just deployed
+                stack.template = change_set.template
+            except Exception as e:
+                LOG.error("Update Stack failed: %s", e, exc_info=LOG.isEnabledFor(logging.WARNING))
+                stack.set_stack_status(StackStatus.UPDATE_FAILED)
+
+        start_worker_thread(_run)
+
+        # TODO: stack id
+        return UpdateStackOutput(StackId=stack.stack_id)
+
     @handler("DeleteStack")
     def delete_stack(
         self,
diff --git a/tests/aws/services/cloudformation/v2/ported_from_v1/api/test_stacks.py b/tests/aws/services/cloudformation/v2/ported_from_v1/api/test_stacks.py
@@ -261,7 +261,6 @@ def test_list_stack_resources_for_removed_resource(self, deploy_cfn_template, aw
         statuses = {res["ResourceStatus"] for res in resources}
         assert statuses == {"UPDATE_COMPLETE"}
 
-    @pytest.mark.skip(reason="CFNV2:Validation")
     @markers.aws.validated
     def test_update_stack_with_same_template_withoutchange(
         self, deploy_cfn_template, aws_client, snapshot
