LCORE-622: ssl_mode in PostgreSQL configuration should contain just limited set of values

Author: tisnik

src/constants.py

@@ -1,6 +1,6 @@
 """Constants used in business logic."""
 
-from typing import Final
+from typing import Final, Literal
 
 # Use Final[type] as type hint for all constants to ensure that type checkers (Mypy etc.)
 # will be able to detect assignements to such constants.
@@ -158,7 +158,7 @@
 
 # PostgreSQL connection constants
 # See: https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-CONNECT-SSLMODE
-POSTGRES_DEFAULT_SSL_MODE: Final[str] = "prefer"
+POSTGRES_DEFAULT_SSL_MODE: Final[Literal["prefer"]] = "prefer"
 # See: https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-CONNECT-GSSENCMODE
 POSTGRES_DEFAULT_GSS_ENCMODE: Final[str] = "prefer"
 

src/models/config.py

@@ -228,8 +228,10 @@ class PostgreSQLDatabaseConfiguration(ConfigurationBase):
         description="Database namespace",
     )
 
-    ssl_mode: str = Field(
-        constants.POSTGRES_DEFAULT_SSL_MODE,
+    ssl_mode: Literal[
+        "disable", "allow", "prefer", "require", "verify-ca", "verify-full"
+    ] = Field(
+        default=constants.POSTGRES_DEFAULT_SSL_MODE,
         title="SSL mode",
         description="SSL mode",
     )