Multi-Event Triggers for Serverless Computing

2025-05-27

AI Summary

Current FaaS platforms support only single-event triggers, failing to express practical multi-event aggregation requirements—such as “every *n*th occurrence” or “cross-type conjunction”—leading to excessive invalid invocations, resource waste, and elevated latency. This paper introduces the first declarative multi-event triggering abstraction tailored for FaaS, enabling cross-type event composition and supporting periodic and cumulative triggering semantics. We design a lightweight trigger engine integrated into the platform’s control plane, requiring no application-side state storage or custom coordination logic. Experiments demonstrate a 62.5% reduction in event-to-invocation latency in fault-detection scenarios; our prototype achieves 300K requests/sec throughput, scaling to large deployments. The core contribution is breaking the single-event granularity barrier, significantly enhancing both the expressiveness and execution efficiency of event-driven logic in FaaS.

Technology Category

• Intelligent Robots: Multimodal Perception & Sensor Fusion
• Computer Vision: Multi-modal Vision
• Multiagent Systems: Multiagent Planning

Application Category

• Search and Retrieval-Augmented AI: Retrieval-Augmented Generation (RAG) and multi-modal RAG
• Systems and Infrastructure for Web, Mobile and WoT: Experiences and lessons learnt from Web-based algorithms and system deployments
• Security and Privacy: Large-scale security measurements

Abstract

Function-as-a-Service (FaaS) is an event-driven serverless cloud computing model in which small, stateless functions are invoked in response to events, such as HTTP requests, new database entries, or messages. Current FaaS platform assume that each function invocation corresponds to a single event. However, from an application perspective, it is desirable to invoke functions in response to a collection of events of different types or only with every n extsuperscript{th} event. To implement this today, a function would need additional state management, e.g., in a database, and custom logic to determine whether its trigger condition is fulfilled and the actual application code should run. In such an implementation, most function invocations would be rendered essentially useless, leading to unnecessarily high resource usage, latency, and cost for applications. In this paper, we introduce multi-event triggers, through which complex conditions for function invocations can be specified. Specifically, we introduce abstractions for invoking functions based on a set of $n$ events and joins of multiple events of different types. This enables application developers to define intricate conditions for function invocations, workflow steps, and complex event processing. Our evaluation with a proof-of-concept prototype shows that this reduces event--invocation latency by 62.5% in an incident detection use-case and that our system can handle more than 300,000 requests per second on limited hardware, which is sufficient load for implementation in large FaaS platforms.

Problem

• Enables functions to trigger on multiple event types
• Reduces unnecessary invocations and resource usage
• Supports complex conditions for event-driven workflows

Innovation

• Introduces multi-event triggers for FaaS
• Enables complex conditions for function invocations
• Reduces latency and handles high request rates