AWSLambda - refactor exception handling

moto/awslambda/models.py

@@ -33,6 +33,11 @@ from moto.s3.models import s3_backend
 from moto.logs.models import logs_backends
 from moto.s3.exceptions import MissingBucket, MissingKey
 from moto import settings
+from .exceptions import (
+    CrossAccountNotAllowed,
+    InvalidRoleFormat,
+    InvalidParameterValueException,
+)
 from .utils import make_function_arn, make_function_ver_arn
 from moto.sqs import sqs_backends
 from moto.dynamodb2 import dynamodb_backends2
@@ -215,9 +220,8 @@ class LambdaFunction(BaseModel):
                 key = s3_backend.get_key(self.code["S3Bucket"], self.code["S3Key"])
             except MissingBucket:
                 if do_validate_s3():
-                    raise ValueError(
-                        "InvalidParameterValueException",
-                        "Error occurred while GetObject. S3 Error Code: NoSuchBucket. S3 Error Message: The specified bucket does not exist",
+                    raise InvalidParameterValueException(
+                        "Error occurred while GetObject. S3 Error Code: NoSuchBucket. S3 Error Message: The specified bucket does not exist"
                     )
             except MissingKey:
                 if do_validate_s3():
@@ -669,28 +673,19 @@ class LambdaStorage(object):
         :param fn: Function
         :type fn: LambdaFunction
         """
-        pattern = r"arn:(aws[a-zA-Z-]*)?:iam::(\d{12}):role/?[a-zA-Z_0-9+=,.@\-_/]+"
-        valid_role = re.match(pattern, fn.role)
+        valid_role = re.match(InvalidRoleFormat.pattern, fn.role)
         if valid_role:
             account = valid_role.group(2)
             if account != ACCOUNT_ID:
-                raise ValueError(
-                    "AccessDeniedException", "Cross-account pass role is not allowed."
-                )
+                raise CrossAccountNotAllowed()
             try:
                 iam_backend.get_role_by_arn(fn.role)
             except IAMNotFoundException:
-                raise ValueError(
-                    "InvalidParameterValueException",
-                    "The role defined for the function cannot be assumed by Lambda.",
+                raise InvalidParameterValueException(
+                    "The role defined for the function cannot be assumed by Lambda."
                 )
         else:
-            raise ValueError(
-                "ValidationException",
-                "1 validation error detected: Value '{0}' at 'role' failed to satisfy constraint: Member must satisfy regular expression pattern: {1}".format(
-                    fn.role, pattern
-                ),
-            )
+            raise InvalidRoleFormat(fn.role)
         if fn.function_name in self._functions:
             self._functions[fn.function_name]["latest"] = fn
         else: