ref #3: [feat] add context and tasks for master-service

domain/error.py

@@ -16,3 +16,19 @@ class UserConflictError(UserError):
     def __init__(self, email: str) -> None:
         super().__init__('user_conflict')
         self.email = email
+
+
+class SandboxError(DomainError):
+    pass
+
+
+class SandboxStartError(SandboxError):
+    def __init__(self, chat_id: str) -> None:
+        super().__init__('sandbox_start_failed')
+        self.chat_id = chat_id
+
+
+class SandboxAlreadyRunningError(SandboxError):
+    def __init__(self, chat_id: str) -> None:
+        super().__init__('sandbox_already_running')
+        self.chat_id = chat_id