This demonstra:on is intended for par:cipants that are interested in programming and debugging IoT systems. We show a novel debugging approach for IoT applica:ons in WOOD. WOOD is an out-of-things debugger for the WebAssembly WARDuino VM which bring ideas of out-of-place debugging to the domain of IoT applications, i.e applications running on devices with restricted computational power and memory capacity. The key idea of WOOD is, upon a failure or reached breakpoint, to bring the state of a remote application running on an IoT device to the developer’s machine. Debugging can then happen at the developer’s machine through a local reconstruction of the remote application. This enables the debugging of IoT applications without shutting them down as well as reducing interference on the target application. Once the developer has fixed the bug, code changes can be committed back to the remote device by means of dynamic sotware updates. Through an extensive interface, WOOD also gives developers full control over the debugging overhead imposed on the device, and the remote access to device hardware resources (e.g., sensors) needed during local debugging.

We start the demonstration with a brief introduction to out-of-things. We then introduce a temperature monitoring application that contains a logical error which we solve using WOOD. To this end, we deploy the faulty application on a M5StickC device (an ESP32 based IoT board representing the thermostat). We then show how to fix the bug in an external machine (i.e. the developers’s machine), and how code changes during the debugging session can be committed back to the M5StickC. We conclude the demonstra:on with other experiments on WOOD to show its scalability and to quantify its overhead (e.g. network, computation, etc.) on devices.