ContextWorkflow: A Monadic DSL for Compensable and Interruptible Executions
Context-aware applications, whose behavior reactively depends on the time-varying status of the surrounding environment—such as network connection, battery level, and sensors—are getting more and more pervasive and important. The term ``context-awareness'' usually suggests prompt reactions to context changes: as the context change signals that the current execution cannot be continued, the application should immediately abort its execution, possibly does some clean-up tasks, and suspend until the context allows it to restart. Interruptions, or asynchronous exceptions, are useful to achieve context-awareness. It is, however, difficult to program with interruptions in a compositional way in most programming languages because their support is too primitive, relying on synchronous exception handling mechanism such as try–catch.
We propose a new domain-specific language ContextWorkflow for interruptible programs as a solution to the problem. A basic unit of an interruptible program is a workflow, i.e., a sequence of atomic computations accompanied with compensation actions. The uniqueness of ContextWorkflow is that, during its execution, a workflow keeps watching the context between atomic actions and decides the computation should be continued, aborted, or suspended. Our contribution of this paper is as follows; (1) the design of a workflow-like language with asynchronous interruption, checkpointing, sub-workflows and suspension; (2) a formal semantics of the core language; (3) a monadic interpreter corresponding to the semantics; and (4) its concrete implementation as an embedded domain-specific language in Scala.
Thu 19 Jul
|11:00 - 11:25|
Ragnar MogkTechnische Universität Darmstadt, Lars BaumgärtnerPhilipps-Universität Marburg, Guido SalvaneschiTU Darmstadt, Bernd FreislebenPhilipps-Universität Marburg, Mira MeziniTU DarmstadtDOI
|11:25 - 11:50|
Hiroaki InoueMitsubishi Electric Corporation, Japan, Tomoyuki AotaniTokyo Institute of Technology, Atsushi IgarashiKyoto University, JapanDOI
|11:50 - 12:15|
|12:15 - 12:40|
Gian NtzikImperial College London, Pedro da Rocha PintoImperial College London, Julian SutherlandImperial College London, Philippa GardnerImperial College LondonDOI