auth: Specify types for privileges, roles, groups

Use specified types for privileges, roles and types rather than using strings
to help with limiting bugs.

* gn3/auth/authorisation/groups.py: Specify and use the `Group` type
* gn3/auth/authorisation/privileges.py: Specify and use the `Privilege` type
* gn3/auth/authorisation/roles.py: Specify the `Role` type. Add the
  `create_role` function.

1 files changed, 41 insertions, 0 deletions

diff --git a/gn3/auth/authorisation/roles.py b/gn3/auth/authorisation/roles.py
new file mode 100644
index 0000000..7c33ab3
--- /dev/null
+++ b/gn3/auth/authorisation/roles.py
@@ -0,0 +1,41 @@
+"""Handle management of roles"""
+from uuid import UUID, uuid4
+from typing import Iterable, NamedTuple
+
+from gn3.auth import db
+
+from .checks import authorised_p
+from .privileges import Privilege
+
+class Role(NamedTuple):
+    """Class representing a role: creates immutable objects."""
+    role_id: UUID
+    role_name: str
+    privileges: Iterable[Privilege]
+
+@authorised_p(("create-role",), error_message="Could not create role")
+def create_role(
+        cursor: db.DbCursor, role_name: str,
+        privileges: Iterable[Privilege]) -> Role:
+    """
+    Create a new generic role.
+
+    PARAMS:
+    * cursor: A database cursor object - This function could be used as part of
+              a transaction, hence the use of a cursor rather than a connection
+              object.
+    * role_name: The name of the role
+    * privileges: A 'list' of privileges to assign the new role
+
+    RETURNS: An immutable `gn3.auth.authorisation.roles.Role` object
+    """
+    role = Role(uuid4(), role_name, privileges)
+
+    cursor.execute(
+        "INSERT INTO roles(role_id, role_name) VALUES (?, ?)",
+        (role.role_id, role.role_name))
+    cursor.execute(
+        "INSERT INTO role_privileges(role_id, privilege_id) VALUES (?, ?)",
+        ((role.role_id, priv.privilege_id) for priv in privileges))
+
+    return role