[ElastiCache] Add support for AuthenticationMode for create_user

moto/elasticache/exceptions.py

@@ -43,6 +43,26 @@ def __init__(self) -> None:
         )
 
 
+class InvalidParameterValueException(ElastiCacheException):
+    code = 404
+
+    def __init__(self, message: str) -> None:
+        super().__init__(
+            "InvalidParameterValue",
+            message=message,
+        )
+
+
+class InvalidParameterCombinationException(ElastiCacheException):
+    code = 404
+
+    def __init__(self, message: str) -> None:
+        super().__init__(
+            "InvalidParameterCombination",
+            message=message,
+        )
+
+
 class UserAlreadyExists(ElastiCacheException):
     code = 404
 

moto/elasticache/models.py

@@ -12,10 +12,12 @@
     CacheClusterAlreadyExists,
     CacheClusterNotFound,
     InvalidARNFault,
+    InvalidParameterCombinationException,
+    InvalidParameterValueException,
     UserAlreadyExists,
     UserNotFound,
 )
-from .utils import PAGINATION_MODEL
+from .utils import PAGINATION_MODEL, AuthenticationTypes
 
 
 class User(BaseModel):
@@ -29,10 +31,12 @@ def __init__(
         engine: str,
         no_password_required: bool,
         passwords: Optional[List[str]] = None,
+        authentication_type: Optional[str] = None,
     ):
         self.id = user_id
         self.name = user_name
         self.engine = engine
+
         self.passwords = passwords or []
         self.access_string = access_string
         self.no_password_required = no_password_required
@@ -41,6 +45,7 @@ def __init__(
         self.usergroupids: List[str] = []
         self.region = region
         self.arn = f"arn:{get_partition(self.region)}:elasticache:{self.region}:{account_id}:user:{self.id}"
+        self.authentication_type = authentication_type
 
 
 class CacheCluster(BaseModel):
@@ -161,9 +166,34 @@ def create_user(
         passwords: List[str],
         access_string: str,
         no_password_required: bool,
+        authentication_type: str,  # contain it to the str in the enums TODO
     ) -> User:
         if user_id in self.users:
             raise UserAlreadyExists
+
+        if authentication_type not in AuthenticationTypes._value2member_map_:
+            raise InvalidParameterValueException(
+                f"Input Authentication type: {authentication_type} is not in the allowed list: [password,no-password-required,iam]"
+            )
+
+        if (
+            no_password_required
+            and authentication_type != AuthenticationTypes.NOPASSWORD
+        ):
+            raise InvalidParameterCombinationException(
+                f"No password required flag is true but provided authentication type is {authentication_type}"
+            )
+
+        if passwords and authentication_type != AuthenticationTypes.PASSWORD:
+            raise InvalidParameterCombinationException(
+                f"Password field is not allowed with authentication type: {authentication_type}"
+            )
+
+        if not passwords and authentication_type == AuthenticationTypes.PASSWORD:
+            raise InvalidParameterCombinationException(
+                "A user with Authentication Mode: password, must have at least one password"
+            )
+
         user = User(
             account_id=self.account_id,
             region=self.region_name,
@@ -173,6 +203,7 @@ def create_user(
             passwords=passwords,
             access_string=access_string,
             no_password_required=no_password_required,
+            authentication_type=authentication_type,
         )
         self.users[user_id] = user
         return user

moto/elasticache/responses.py

@@ -1,7 +1,12 @@
 from moto.core.responses import BaseResponse
 
-from .exceptions import PasswordRequired, PasswordTooShort
+from .exceptions import (
+    InvalidParameterCombinationException,
+    InvalidParameterValueException,
+    PasswordTooShort,
+)
 from .models import ElastiCacheBackend, elasticache_backends
+from .utils import AuthenticationTypes
 
 
 class ElastiCacheResponse(BaseResponse):
@@ -21,12 +26,41 @@
         user_name = params.get("UserName")
         engine = params.get("Engine")
         passwords = params.get("Passwords", [])
-        no_password_required = self._get_bool_param("NoPasswordRequired", False)
-        password_required = not no_password_required
-        if password_required and not passwords:
-            raise PasswordRequired
+        no_password_required = self._get_bool_param("NoPasswordRequired")
+        authentication_mode = params.get("AuthenticationMode")
+        authentication_type = "null"
+
+        if no_password_required is not None:
+            authentication_type = (
+                AuthenticationTypes.NOPASSWORD.value
+                if no_password_required
+                else AuthenticationTypes.PASSWORD.value
+            )
+
+        if passwords:
+            authentication_type = AuthenticationTypes.PASSWORD.value
+
+        if authentication_mode:
+            for key in authentication_mode.keys():
+                if key not in ["Type", "Passwords"]:
+                    raise InvalidParameterValueException(
+                        f'Unknown parameter in AuthenticationMode: "{key}", must be one of: Type, Passwords'
+                    )
+
+            authentication_type = authentication_mode.get("Type")
+            authentication_passwords = authentication_mode.get("Passwords", [])
+
+            if passwords and authentication_passwords:
+                raise InvalidParameterCombinationException(
+                    "Passwords provided via multiple arguments. Use only one argument"
+                )
+
+            # if passwords is empty, then we can use the authentication_passwords
+            passwords = passwords if passwords else authentication_passwords
+
         if any([len(p) < 16 for p in passwords]):
             raise PasswordTooShort
+
         access_string = params.get("AccessString")
         user = self.elasticache_backend.create_user(
             user_id=user_id,  # type: ignore[arg-type]
@@ -35,6 +69,7 @@
             passwords=passwords,
             access_string=access_string,  # type: ignore[arg-type]
             no_password_required=no_password_required,
+            authentication_type=authentication_type,
         )
         template = self.response_template(CREATE_USER_TEMPLATE)
         return template.render(user=user)
@@ -167,7 +202,9 @@
       {% if user.no_password_required %}
       <Type>no-password</Type>
       {% else %}
-      <Type>password</Type>
+      <Type>{{ user.authentication_type }}</Type>
+      {% endif %}
+      {% if user.passwords %}
       <PasswordCount>{{ user.passwords|length }}</PasswordCount>
       {% endif %}
     </Authentication>

moto/elasticache/utils.py

@@ -1,3 +1,5 @@
+from enum import Enum
+
 PAGINATION_MODEL = {
     "describe_cache_clusters": {
         "input_token": "marker",
@@ -6,3 +8,9 @@
         "unique_attribute": "cache_cluster_id",
     },
 }
+
+
+class AuthenticationTypes(str, Enum):
+    NOPASSWORD = "no-password-required"
+    PASSWORD = "password"
+    IAM = "iam"