Call cfn-lint for module fragments

README.md

@@ -55,6 +55,16 @@ cfn test --enforce-timeout 60 #set the RL handler timeout to 60 seconds and CUD
 cfn test --enforce-timeout 60 -- -k contract_delete_update # combine args
 ```
 
+### Command: validate
+
+To validate the schema, use the `validate` command.
+
+This command is automatically run whenever one attempts to submit a resource or module. Any module fragments will be automatically validated via [`cfn-lint`](https://github.com/aws-cloudformation/cfn-python-lint/), however any warnings or errors detected by [`cfn-lint`](https://github.com/aws-cloudformation/cfn-python-lint/) will not cause this step to fail.
+
+```bash
+cfn validate
+```
+
 ### Command: build-image
 
 To build an image for a resource type. This image provides a minimalistic execution environment for the resource handler that does not depend on AWS Lambda in anyway. This image can be used during cfn invoke and cfn test instead of using sam cli.

setup.cfg

@@ -29,7 +29,7 @@ include_trailing_comma = true
 combine_as_imports = True
 force_grid_wrap = 0
 known_first_party = rpdk
-known_third_party = boto3,botocore,colorama,docker,hypothesis,jinja2,jsonschema,ordered_set,pkg_resources,pytest,pytest_localserver,setuptools,yaml
+known_third_party = boto3,botocore,cfnlint,colorama,docker,hypothesis,jinja2,jsonschema,ordered_set,pkg_resources,pytest,pytest_localserver,setuptools,yaml
 
 [tool:pytest]
 # can't do anything about 3rd part modules, so don't spam us

setup.py

@@ -51,6 +51,7 @@ def find_version(*file_paths):
         "colorama>=0.4.1",
         "docker>=4.3.1",
         "ordered-set>=4.0.2",
+        "cfn-lint>=0.43.0",
     ],
     entry_points={
         "console_scripts": ["cfn-cli = rpdk.core.cli:main", "cfn = rpdk.core.cli:main"]

src/rpdk/core/fragment/generator.py

@@ -11,6 +11,8 @@
 import os
 from pathlib import Path
 
+import cfnlint.config
+import cfnlint.core
 import yaml
 
 from rpdk.core.data_loaders import resource_json
@@ -75,11 +77,45 @@ def validate_fragments(self):
         self.__validate_no_transforms_present(raw_fragments)
         self.__validate_outputs(raw_fragments)
         self.__validate_mappings(raw_fragments)
+        lint_warnings = self.__validate_fragment_through_cfn_lint(raw_fragments)
+        if not lint_warnings:
+            LOG.warning("Module fragment is valid.")
+        else:
+            LOG.warning(
+                "Module fragment is probably valid, but there are "
+                "warnings/errors from cfn-lint "
+                "(https://github.com/aws-cloudformation/cfn-python-lint):"
+            )
+        for lint_warning in lint_warnings:
+            print(
+                "\t{} (from rule {})".format(lint_warning.message, lint_warning.rule),
+            )
 
     def __validate_outputs(self, raw_fragments):
         self.__validate_no_exports_present(raw_fragments)
         self.__validate_output_limit(raw_fragments)
 
+    @staticmethod
+    def __validate_fragment_through_cfn_lint(raw_fragment):
+        filename = "temporary_fragment.json"
+
+        with open(filename, "w") as outfile:
+            json.dump(raw_fragment, outfile, indent=4)
+
+        template = cfnlint.decode.cfn_json.load(filename)
+
+        # Initialize the ruleset to be applied (no overrules, no excludes)
+        # Runs Warning and Error rules
+        rules = cfnlint.core.get_rules([], [], [], [], False, [])
+
+        regions = ["us-east-1"]
+
+        matches = cfnlint.core.run_checks(filename, template, rules, regions)
+
+        os.remove(filename)
+
+        return matches
+
     @staticmethod
     def __validate_no_exports_present(raw_fragments):
         if "Outputs" in raw_fragments:

src/rpdk/core/project.py

@@ -428,6 +428,7 @@ def load(self):
             LOG.info("Validating your resource specification...")
             try:
                 self.load_schema()
+                LOG.warning("Resource schema is valid.")
             except FileNotFoundError as e:
                 self._raise_invalid_project("Resource specification not found.", e)
             except SpecValidationError as e:

src/rpdk/core/validate.py

@@ -13,8 +13,6 @@ def validate(_args):
     project = Project()
     project.load()
 
-    LOG.warning("Resource schema for %s is valid", project.type_name)
-
 
 def setup_subparser(subparsers, parents):
     parser = subparsers.add_parser("validate", description=__doc__, parents=parents)

tests/data/sample_fragments/template_without_parameter_section.json

@@ -5,6 +5,7 @@
         "S3Bucket": {
             "Type": "AWS::S3::Bucket",
             "DeletionPolicy": "Retain",
+            "UpdateReplacePolicy": "Retain",
             "Properties": {
                 "VersioningConfiguration": {
                     "Status": "Enabled"

tests/test_project.py

@@ -653,6 +653,17 @@ def test_load_module_project_succeeds(project):
         project.load()
 
 
+def test_load_resource_succeeds(project):
+    project.artifact_type = "Resource"
+    project.type_name = "Unit::Test::Resource"
+    patch_load_settings = patch.object(
+        project, "load_settings", return_value={"artifact_type": "RESOURCE"}
+    )
+    project._write_example_schema()
+    with patch_load_settings:
+        project.load()
+
+
 def test_load_module_project_with_invalid_fragments(project):
     project.artifact_type = "MODULE"
     project.type_name = "Unit::Test::Malik::MODULE"