A large class of IoT applications read sensors, execute application logic, and actuate actuators. However, the lack of high-level programming abstractions compromises correctness especially in presence of failures and unwanted interleaving between applications. A key problem arises when operations on IoT devices or the application itself fails, which leads to inconsistencies between the physical state and application state, breaking application semantics and causing undesired consequences. Transactions are a well-established abstraction for correctness, but assume properties that are absent in an IoT context. In this paper, we study one such environment, smart home, and establish inconsistencies manifesting out of failures. We propose an abstraction called transactuation that empowers developers to build reliable applications. Our runtime, Relacs, implements the abstraction atop a real smart-home platform. We evaluate programmability, performance, and effectiveness of transactuations to demonstrate its potential as a powerful abstraction and execution model.
