APEX: Automatic precondition execution with isolation and atomicity in internet-of-things

In Internet-of-Things there are situations where before users can execute commands on IoT devices, certain conditions must be met for sake of safety, correctness or efficiency. Thus, a series of other commands need to precede the user commands in a correct order to make those conditions true. Users have to consciously follow the order and manually send those commands one by one, which is error prone and inconvenient. We propose APEX, a system automatically deducing, satisfying all the preconditions of the user commands. It has two strategies. Evaluation on a 20-node testbed proves that our conservative strategy sustains high execution success rates despite resource contention, while in realistic enterprise environments, our aggressive strategy may execute significantly faster, saving up to 7s and reducing about 46% of conservative strategy's time cost.