CloudFormation: Update AWS::EC2::LaunchTemplate by physical ID rather than by name (#7149)

moto/ec2/models/launch_templates.py

@@ -167,11 +167,10 @@ class LaunchTemplate(TaggedEC2Resource, CloudFormationModel):
 
         properties = cloudformation_json["Properties"]
 
-        name = properties.get("LaunchTemplateName")
         data = properties.get("LaunchTemplateData")
         description = properties.get("VersionDescription")
 
-        launch_template = backend.get_launch_template_by_name(name)
+        launch_template = backend.get_launch_template(original_resource.id)
 
         launch_template.create_version(data, description)
 

tests/test_ec2/test_launch_templates_cloudformation.py

@@ -297,3 +297,84 @@ def test_two_launch_templates():
         launch_templates["LaunchTemplates"][0]["LaunchTemplateName"]
         != launch_templates["LaunchTemplates"][1]["LaunchTemplateName"]
     )
+
+
+@mock_autoscaling
+@mock_cloudformation
+@mock_ec2
+def test_launch_template_unnamed_update():
+    cf_client = boto3.client("cloudformation", region_name="us-west-1")
+    ec2_client = boto3.client("ec2", region_name="us-west-1")
+
+    stack_name = str(uuid4())
+
+    template_json = json.dumps(
+        {
+            "AWSTemplateFormatVersion": "2010-09-09",
+            "Description": "AWS CloudFormation Template to create a LaunchTemplate",
+            "Resources": {
+                "LaunchTemplate": {
+                    "Type": "AWS::EC2::LaunchTemplate",
+                    "Properties": {
+                        "LaunchTemplateData": {
+                            "ImageId": EXAMPLE_AMI_ID,
+                            "InstanceType": "t3.small",
+                            "UserData": "",
+                        },
+                    },
+                },
+            },
+        }
+    )
+
+    cf_client.create_stack(
+        StackName=stack_name,
+        TemplateBody=template_json,
+        Capabilities=["CAPABILITY_NAMED_IAM"],
+        OnFailure="DELETE",
+    )
+
+    launch_template_resource = cf_client.describe_stack_resources(
+        StackName=stack_name, LogicalResourceId="LaunchTemplate"
+    )["StackResources"][0]
+    launch_template_id = launch_template_resource["PhysicalResourceId"]
+    launch_template = ec2_client.describe_launch_templates(
+        LaunchTemplateIds=[launch_template_id]
+    )["LaunchTemplates"][0]
+    assert launch_template["LatestVersionNumber"] == 1
+
+    template_json = json.dumps(
+        {
+            "AWSTemplateFormatVersion": "2010-09-09",
+            "Description": "AWS CloudFormation Template to create a LaunchTemplate",
+            "Resources": {
+                "LaunchTemplate": {
+                    "Type": "AWS::EC2::LaunchTemplate",
+                    "Properties": {
+                        "LaunchTemplateData": {
+                            "ImageId": EXAMPLE_AMI_ID,
+                            "InstanceType": "t3.medium",
+                            "UserData": "",
+                        },
+                    },
+                },
+            },
+        }
+    )
+
+    cf_client.update_stack(
+        StackName=stack_name,
+        TemplateBody=template_json,
+        Capabilities=["CAPABILITY_NAMED_IAM"],
+    )
+
+    updated_launch_template_resource = cf_client.describe_stack_resources(
+        StackName=stack_name, LogicalResourceId="LaunchTemplate"
+    )["StackResources"][0]
+    updated_launch_template_id = updated_launch_template_resource["PhysicalResourceId"]
+    updated_launch_template = ec2_client.describe_launch_templates(
+        LaunchTemplateIds=[updated_launch_template_id]
+    )["LaunchTemplates"][0]
+
+    assert launch_template_id == updated_launch_template_id
+    assert updated_launch_template["LatestVersionNumber"] == 2