Feat: conversation variable & variable assigner node (#7222)

Signed-off-by: -LAN- <laipz8200@outlook.com>
Co-authored-by: Joel <iamjoel007@gmail.com>
Co-authored-by: -LAN- <laipz8200@outlook.com>

api/models/__init__.py

@@ -1,15 +1,19 @@
 from enum import Enum
 
-from sqlalchemy import CHAR, TypeDecorator
-from sqlalchemy.dialects.postgresql import UUID
+from .model import AppMode
+from .types import StringUUID
+from .workflow import ConversationVariable, WorkflowNodeExecutionStatus
+
+__all__ = ['ConversationVariable', 'StringUUID', 'AppMode', 'WorkflowNodeExecutionStatus']
 
 
 class CreatedByRole(Enum):
     """
     Enum class for createdByRole
     """
-    ACCOUNT = "account"
-    END_USER = "end_user"
+
+    ACCOUNT = 'account'
+    END_USER = 'end_user'
 
     @classmethod
     def value_of(cls, value: str) -> 'CreatedByRole':
@@ -23,49 +27,3 @@ class CreatedByRole(Enum):
             if role.value == value:
                 return role
         raise ValueError(f'invalid createdByRole value {value}')
-
-
-class CreatedFrom(Enum):
-    """
-    Enum class for createdFrom
-    """
-    SERVICE_API = "service-api"
-    WEB_APP = "web-app"
-    EXPLORE = "explore"
-
-    @classmethod
-    def value_of(cls, value: str) -> 'CreatedFrom':
-        """
-        Get value of given mode.
-
-        :param value: mode value
-        :return: mode
-        """
-        for role in cls:
-            if role.value == value:
-                return role
-        raise ValueError(f'invalid createdFrom value {value}')
-
-
-class StringUUID(TypeDecorator):
-    impl = CHAR
-    cache_ok = True
-
-    def process_bind_param(self, value, dialect):
-        if value is None:
-            return value
-        elif dialect.name == 'postgresql':
-            return str(value)
-        else:
-            return value.hex
-
-    def load_dialect_impl(self, dialect):
-        if dialect.name == 'postgresql':
-            return dialect.type_descriptor(UUID())
-        else:
-            return dialect.type_descriptor(CHAR(36))
-
-    def process_result_value(self, value, dialect):
-        if value is None:
-            return value
-        return str(value)