Validate that helm chart values exist (#138)

* add validation of the default values for helm charts

* Add unit tests

* update HISTORY.rst

* Markups

src/aosm/HISTORY.rst

@@ -8,6 +8,7 @@ Unreleased
 * Add `publisher` command group for management of publisher resources.
 * Changed the name of the `path_to_mappings` parameter in the CNF input file to `default_values`
 * Added a `helm template` validation step to the `az aosm nfd build` command for the `cnf` definition type
+* Added validation of the values file for helm charts when using the `az aosm nfd build` command for the `cnf` definition type
 * Fixed helm chart image parsing in the `az aosm nfd build` command for the `cnf` definition type. This means that the images can now be extracted correctly from the helm chart.
 * Fixed: infinite loop bug when retrying failed artifact uploads to the ACR
 

src/aosm/azext_aosm/cli_handlers/onboarding_cnf_handler.py

@@ -152,9 +152,16 @@ def _validate_helm_template(self):
 
             raise ValidationError(error_message)
 
+    def _validate_helm_values(self):
+        for helm_processor in self.processors:
+            helm_processor.input_artifact.validate_values()
+
     def pre_validate_build(self):
         """Run all validation functions required before building the cnf."""
         logger.debug("Pre-validating build")
+
+        self._validate_helm_values()
+
         if self.skip != HELM_TEMPLATE:
             self._validate_helm_template()
 

src/aosm/azext_aosm/common/exceptions.py

@@ -17,5 +17,5 @@ class SchemaGetOrGenerateError(Exception):
     """Raised when the schema cannot be generated or retrieved"""
 
 
-class DefaultValuesNotFoundError(Exception):
+class DefaultValuesNotFoundError(UserFault):
     """Raised when the default values file cannot be found"""

src/aosm/azext_aosm/inputs/helm_chart_input.py

@@ -196,30 +196,37 @@ def validate_template(self) -> None:
             )
             return error_message
 
-    def get_defaults(self) -> Dict[str, Any]:
+    def validate_values(self) -> None:
         """
-        Retrieves the default values for the Helm chart.
+        Confirm that the values.yaml file exists in the Helm chart directory
+        or that the default values are provided.
 
-        :return: The default values for the Helm chart.
-        :rtype: Dict[str, Any]
-        :raises DefaultValuesNotFoundError: If no default values were found for the Helm chart.
+        :raises DefaultValuesNotFoundError: If the values.yaml and default values do not exist.
         """
-        logger.info("Getting default values for Helm chart input")
 
-        try:
-            default_config = self.default_config or self._read_values_yaml()
-            logger.debug(
-                "Default values for Helm chart input: %s",
-                json.dumps(default_config, indent=4),
-            )
-            return copy.deepcopy(default_config)
-        except FileNotFoundError as error:
-            logger.error("No default values found for Helm chart '%s'", self.chart_path)
+        default_config = self.default_config or self._read_values_yaml()
+
+        if not default_config:
+            logger.error("No values found for Helm chart '%s'", self.chart_path)
             raise DefaultValuesNotFoundError(
                 "ERROR: No default values found for the Helm chart"
                 f" '{self.chart_path}'. Please provide default values"
                 " or add a values.yaml file to the Helm chart."
-            ) from error
+            )
+
+    def get_defaults(self) -> Dict[str, Any]:
+        """
+        Retrieves the default values for the Helm chart.
+
+        :return: The default values for the Helm chart.
+        :rtype: Dict[str, Any]
+        """
+        default_config = self.default_config or self._read_values_yaml()
+        logger.debug(
+            "Default values for Helm chart input: %s",
+            json.dumps(default_config, indent=4),
+        )
+        return copy.deepcopy(default_config)
 
     def get_schema(self) -> Dict[str, Any]:
         """
@@ -244,10 +251,10 @@ def get_schema(self) -> Dict[str, Any]:
                         schema = json.load(schema_file)
 
             if not schema:
-                # Otherwise, generate a schema from the default values in values.yaml.
-                logger.debug("Generating schema from values.yaml")
+                # Otherwise, generate a schema from the default values or values in values.yaml.
+                logger.debug("Generating schema from default values")
                 built_schema = genson.Schema()
-                built_schema.add_object(self._read_values_yaml())
+                built_schema.add_object(self.get_defaults())
                 schema = built_schema.to_dict()
 
             logger.debug(
@@ -412,11 +419,5 @@ def _read_values_yaml(self) -> Dict[str, Any]:
                     content = yaml_processor.load(f)
                 return content
 
-        logger.error("No values.yaml file found in Helm chart '%s'", self.chart_path)
-        raise FileNotFoundError(
-            f"ERROR: No values file was found in the Helm chart"
-            f" '{self.chart_path}'."
-        )
-
     def __del__(self):
         shutil.rmtree(self._temp_dir_path)

src/aosm/azext_aosm/tests/latest/unit_test/test_helm_chart_input.py

@@ -2,13 +2,16 @@
 # Copyright (c) Microsoft Corporation. All rights reserved.
 # Licensed under the MIT License. See License.txt in the project root for license information.
 # --------------------------------------------------------------------------------------------
+import logging
 from unittest import TestCase
 from pathlib import Path
 import os
+import sys
 
 from azext_aosm.inputs.helm_chart_input import (
     HelmChartInput,
 )
+from azext_aosm.common.exceptions import DefaultValuesNotFoundError
 
 code_directory = os.path.dirname(__file__)
 parent_directory = os.path.abspath(os.path.join(code_directory, ".."))
@@ -21,6 +24,9 @@
 class TestHelmChartInput(TestCase):
     """Test the HelmChartInput class."""
 
+    def setUp(self):
+        logging.basicConfig(level=logging.INFO, stream=sys.stdout)
+
     def test_validate_template_valid_chart(self):
         """Test validating a valid Helm chart using helm template."""
 
@@ -56,3 +62,51 @@ def test_validate_template_invalid_chart(self):
         output = helm_chart_input.validate_template()
 
         assert output != ""
+
+    def test_validate_values(self):
+        """Test validating whether values exist in a helm chart."""
+
+        helm_chart_input = HelmChartInput(
+            artifact_name="test-invalid",
+            artifact_version="1.0.0",
+            chart_path=Path(
+                os.path.join(
+                    helm_charts_directory,
+                    VALID_CHART_NAME,
+                )
+            ),
+        )
+
+        helm_chart_input.validate_values()
+
+        # Use an Invalid chart (because it does not have values.yaml in it),
+        # but provide a default config parameter which will override those values.
+        helm_chart_input_with_default_values = HelmChartInput(
+            artifact_name="test-default-values",
+            artifact_version="1.0.0",
+            chart_path=Path(
+                os.path.join(
+                    helm_charts_directory,
+                    INVALID_CHART_NAME,
+                )
+            ),
+            default_config={"test": "test"},
+        )
+
+        helm_chart_input_with_default_values.validate_values()
+
+    def test_validate_invalid_values(self):
+        """Test validating a helm chart with values.yaml missing."""
+        helm_chart_input = HelmChartInput(
+            artifact_name="test-invalid",
+            artifact_version="1.0.0",
+            chart_path=Path(
+                os.path.join(
+                    helm_charts_directory,
+                    INVALID_CHART_NAME,
+                )
+            ),
+        )
+
+        with self.assertRaises(DefaultValuesNotFoundError):
+            helm_chart_input.validate_values()