Event-based Customisation of Multi-Tenant SaaS Using Microservices

Context: For software vendors to exploit economies of scale, enterprise software such as CRM and ERP are now made available on the Cloud with a multi-tenant Software as a Service model. The increased value comes from the ability of vendors to serve multiple tenants, with the same instance. Objective: For tenants to widely adopt Cloud-based multi-tenant SaaS, new customisation solutions are required. In this Master’s project, we present an event-based non-intrusive customisation framework. The framework enables customisation for multi-tenant SaaS by leveraging the existing events in the application. Method: Based on a review of the literature on customisation of multi-tenant SaaS and the requirement that the expression power should be equal to deep customisation, an approach is created and applied to a case study. Results: The results of the case study done on eShopOnContainers show that an event-based customisation approach can empower an application to give the ability to customise the flow of processing events, and integrate with tenant-specific microservices for customisation. Conclusions: A crucial aspect for vendors of multi-tenant cloud SaaS applications is ensuring tenant-isolation, our approach maintains tenant-isolation by altering the messaging framework to be multi-tenant aware. Another upside to an event-based customisation approach is the ability to reduce the number of API calls