Context-oriented programming for customizable SaaS applications

Abstract

Software-as-a-Service (SaaS) applications are multi-tenant software applications that are delivered as highly configurable web services to individual customers, which are called tenants in this context. For reasons of complexity management and to lower maintenance cost, SaaS providers maintain and deploy a single version of the application code for all tenants. As a result, however, custom-made extensions for individual tenants cannot be e ciently integrated and managed. In this paper we show that by using a context-oriented programming model, cross-tier tenant-specific software variations can be easily integrated into the single-version application code base. Moreover, the selection of which variations to execute can be configured on a per tenant basis. Concretely, we provide a technical case study based on Google App Engine (GAE), a cloud platform for building multitenant web applications. We contribute by showing: (a) how ContextJ, a context-oriented programming (COP) language, can be used with GAE, (b) the increase in flexibility and customizability of tenant-specific software variations using ContextJ as compared to Google's dependency injection framework Guice, and (c) that the performance of using ContextJ is comparable to Guice. Based on these observations, we come to the conclusion that COP can be helpful for providing software variations in SaaS.

A nonintrusive approach for implementing single database, multitenant services from web applications

“…The source code of this implementation, both the original 14 and Multitenant 15 versions, is freely available. This reference implementation was developed as the working example for a tutorial article published elsewhere that presents a step by step description of how to create the Service starting from the Web Application [12] 16 . A reusable Ruby on Rails implementation of the proposed mechanism 17 and a reference application using it 18 are also available.…”

A Systematic Mapping Study on the Multi-tenant Architecture of SaaS Systems

“…Due to the complexity of the management and maintenance costs, SaaS providers commonly develop a single version of the application for all tenants. Truyen et al [12] evaluated the context-oriented programming (COP) for such applications aiming to improve their development process. The main idea was to enable the customization of specific requirements for each tenant, providing positive results in terms of development effort.…”

“…b) Performance: MTA has introduced new challenges related to load balancing and resource allocation, including the requests on the tenant level, service level agreement, performance objectives and quality of services. Sun et al [18] Implementing Context-oriented programming [12] Guide to implementing new tenants without impacting those already deployed [7] Frameworks Process to support the portability, customization, security and scalability [14] Framework to address availability, extensibility and scalability in a multi-tenant application [17] Migrating Process to support the migrating of conventional web applications towards multi-tenant SaaS application with relatively less effort [16] proposed a suitable load balancing policy for a multi-tenant environment to provide satisfactory quality of services. On a database level, Moon et al [19] presented a load balancer for multi-tenant databases to increase the performance and sharing of resources among tenants.…”

Modularizing tenant-specific schema customization in SaaS applications

“…In our view, any tenant-specific customizations, application layer or data layer, are cross-cutting concerns of a multi-tenant application, and thus should be modularized so that tenants are able to develop, deploy, and integrate to such customizations to the virtualized application with minimal additional programming and configuration efforts. In application layer, most concerns can be modularized by either intercepting filters [4], aspects [5,6], or contexts [8]. On the other hand, although it is generally agreed that the multi-tenant data layer is one of the most important concerns [7], there is little investigation on modularizing data layer concerns in a multi-tenant application.…”