Abstract

Internet-based e-services require application developers to deal explicitly with failures of the underlying software components, for example web servers, servlets, browser sessions, and so forth. This
complicates application programming, and may expose failures to end users. This paper presents a framework for an application-independent infrastructure that provides recovery guarantees and
masks almost all system failures, thus relieving the application programmer from having to deal with these failures—by making applications “stateless.” The main concept is an interaction contract
between two components regarding message and state preservation. The framework provides comprehensive recovery encompassing data, messages, and the states of application components. We describe techniques to reduce logging cost, allow effective log truncation, and permit independent recovery for critical components. We illustrate the framework’s utility via web-based e-services scenarios. Its feasibility is demonstrated by our prototype implementation of interaction contracts based on the Apache web server and thePHPservlet engine. Finally,we discuss industrial relevance
for middleware architectures such as .Net or J2EE.