Service contracts characterise the desired behavioural compliance of a composition of services. Compliance is typically defined by the fulfilment of all service requests through service offers, as dictated by a given Service-Level Agreement (SLA). Contract automata are a recently introduced formalism for specifying and composing service contracts. Based on the notion of synthesis of the most permissive controller from Supervisory Control Theory, a safe orchestration of contract automata can be computed that refines a composition into a compliant one. To model more fine-grained SLA and more adaptive service orchestrations, in this paper we endow contract automata with two orthogonal layers of variability: (i) at the structural level, constraints over service requests and offers define different configurations of a contract automaton, depending on which requests and offers are selected or discarded, and (ii) at the behavioural level, service requests of different levels of criticality can be declared, which induces the novel notion of semi-controllability. The synthesis of orchestrations is thus extended to respect both the structural and the behavioural variability constraints. Finally, we show how to efficiently compute the orchestration of all configurations from only a subset of these configurations. A prototypical tool supports the developed theory.

Controller synthesis of service contracts with variability

Degano P.;Ferrari G. -L.;
2020-01-01

Abstract

Service contracts characterise the desired behavioural compliance of a composition of services. Compliance is typically defined by the fulfilment of all service requests through service offers, as dictated by a given Service-Level Agreement (SLA). Contract automata are a recently introduced formalism for specifying and composing service contracts. Based on the notion of synthesis of the most permissive controller from Supervisory Control Theory, a safe orchestration of contract automata can be computed that refines a composition into a compliant one. To model more fine-grained SLA and more adaptive service orchestrations, in this paper we endow contract automata with two orthogonal layers of variability: (i) at the structural level, constraints over service requests and offers define different configurations of a contract automaton, depending on which requests and offers are selected or discarded, and (ii) at the behavioural level, service requests of different levels of criticality can be declared, which induces the novel notion of semi-controllability. The synthesis of orchestrations is thus extended to respect both the structural and the behavioural variability constraints. Finally, we show how to efficiently compute the orchestration of all configurations from only a subset of these configurations. A prototypical tool supports the developed theory.
2020
Basile, D.; ter Beek, M. H.; Degano, P.; Legay, A.; Ferrari, G. -L.; Gnesi, S.; Di Giandomenico, F.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11568/1066091
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 16
  • ???jsp.display-item.citation.isi??? 13
social impact