Edgar: Offloading Function Execution to the Ultimate Edge : Technical Report

Web applications are on the rise and rapidly evolve into mature replacements for their native counterparts. This trend is mainly driven by the attainment of platform-independence and instant deployability. While web applications are getting more and more complex, scalability and responsiveness remain key challenges that are addressed by rather costly approaches such as cloud computing. In this paper, we present Edgar, a novel middleware for web applications that enables client-side execution of code usually requiring server-side deployment due to missing trust in clients. Following the paradigm of Function-as-a-Service, applications consist of functions that can be distributed to browsers. Other nearby browsers can discover these functions and then directly invoke them on a peer-to-peer basis. Thus, client-side resources are used to provision the web application, which generates lower costs for service providers. Offering premium services such as liberation from ads can be used to incentivise users to provide their resources. In case of resource shortage or unresponsive clients, execution falls back to a cloud-based infrastructure. Edgar combines WebAssembly for executing workloads written in different languages at near-native speed, WebRTC for browser-to-browser communication and Intel SGX to establish trust in other browser’s  computations.We evaluate Edgar by implementing a digital assistant as well as a recommendation system. Our evaluation shows that Edgar generates lower costs than traditional deployments, scales linearly with increasing client numbers and manages unresponsive clients well.