feat(validator): include missing data elements from a validation error (#686)

Author: Michael Brewer

aws_lambda_powertools/utilities/validation/base.py

@@ -32,6 +32,15 @@ def validate_data_against_schema(data: Union[Dict, str], schema: Dict, formats:
         fastjsonschema.validate(definition=schema, data=data, formats=formats)
     except (TypeError, AttributeError, fastjsonschema.JsonSchemaDefinitionException) as e:
         raise InvalidSchemaFormatError(f"Schema received: {schema}, Formats: {formats}. Error: {e}")
-    except fastjsonschema.JsonSchemaException as e:
-        message = f"Failed schema validation. Error: {e.message}, Path: {e.path}, Data: {e.value}"  # noqa: B306, E501
-        raise SchemaValidationError(message)
+    except fastjsonschema.JsonSchemaValueException as e:
+        message = f"Failed schema validation. Error: {e.message}, Path: {e.path}, Data: {e.value}"
+        raise SchemaValidationError(
+            message,
+            validation_message=e.message,
+            name=e.name,
+            path=e.path,
+            value=e.value,
+            definition=e.definition,
+            rule=e.rule,
+            rule_definition=e.rule_definition,
+        )

aws_lambda_powertools/utilities/validation/exceptions.py

@@ -1,9 +1,59 @@
+from typing import Any, List, Optional
+
 from ...exceptions import InvalidEnvelopeExpressionError
 
 
 class SchemaValidationError(Exception):
     """When serialization fail schema validation"""
 
+    def __init__(
+        self,
+        message: str,
+        validation_message: Optional[str] = None,
+        name: Optional[str] = None,
+        path: Optional[List] = None,
+        value: Optional[Any] = None,
+        definition: Optional[Any] = None,
+        rule: Optional[str] = None,
+        rule_definition: Optional[Any] = None,
+    ):
+        """
+
+        Parameters
+        ----------
+        message : str
+            Powertools formatted error message
+        validation_message : str, optional
+            Containing human-readable information what is wrong
+            (e.g. `data.property[index] must be smaller than or equal to 42`)
+        name : str, optional
+            name of a path in the data structure
+            (e.g. `data.property[index]`)
+        path: List, optional
+            `path` as an array in the data structure
+            (e.g. `['data', 'property', 'index']`),
+        value : Any, optional
+            The invalid value
+        definition : Any, optional
+            The full rule `definition`
+            (e.g. `42`)
+        rule : str, optional
+            `rule` which the `data` is breaking
+            (e.g. `maximum`)
+        rule_definition : Any, optional
+            The specific rule `definition`
+            (e.g. `42`)
+        """
+        super().__init__(message)
+        self.message = message
+        self.validation_message = validation_message
+        self.name = name
+        self.path = path
+        self.value = value
+        self.definition = definition
+        self.rule = rule
+        self.rule_definition = rule_definition
+
 
 class InvalidSchemaFormatError(Exception):
     """When JSON Schema is in invalid format"""

tests/functional/validator/test_validator.py

@@ -1,3 +1,5 @@
+import re
+
 import jmespath
 import pytest
 from jmespath import functions
@@ -22,8 +24,22 @@ def test_validate_base64_string_envelope(schema, wrapped_event_base64_json_strin
 
 
 def test_validate_event_does_not_conform_with_schema(schema):
-    with pytest.raises(exceptions.SchemaValidationError):
-        validate(event={"message": "hello_world"}, schema=schema)
+    data = {"message": "hello_world"}
+    message = "data must contain ['message', 'username'] properties"
+    with pytest.raises(
+        exceptions.SchemaValidationError,
+        match=re.escape(f"Failed schema validation. Error: {message}, Path: ['data'], Data: {data}"),
+    ) as e:
+        validate(event=data, schema=schema)
+
+    assert str(e.value) == e.value.message
+    assert e.value.validation_message == message
+    assert e.value.name == "data"
+    assert e.value.path is not None
+    assert e.value.value == data
+    assert e.value.definition == schema
+    assert e.value.rule == "required"
+    assert e.value.rule_definition == schema.get("required")
 
 
 def test_validate_json_string_no_envelope(schema, wrapped_event_json_string):