Histrio: a Serverless Actor System

The serverless paradigm has gained significant traction for cloud applications, offering scalability while offloading infrastructure management and resource provisioning to providers. However, its adoption introduces a shift in programming models, adding complexity to software development. In Function-as-a-Service (FaaS), functions are stateless, requiring developers to manage external storage, concurrency, and state consistency, diverting focus from business logic. This paper presents Histrio, a programming model and execution environment that simplifies developing stateful FaaS applications. Built on the actor programming model, Histrio abstracts state management, database interaction, and concurrency, enhancing the actor model to optimize storage interactions. It ensures exactly-once processing, masking failures and guaranteeing consistent behavior. Compared to traditional FaaS implementations, Histrio reduces development complexity by minimizing operational code, while remaining scalable and configurable to balance performance and costs.