Governing the service-chain: Challenges ahead

As Information Systems are evolving into an ecosystem of services, organizations face the persistent challenge of IT governance. In such a context, Cloud Computing shift has supported a growing service chain that has transformed the business model from industry. In this position paper we outline the dimensions of this service chain reality and the role of Service Level Agreement as a foundation to support its governance challenge

Automating SLA-Driven API Development with SLA4OAI

The OpenAPI Specification (OAS) is the de facto standard to describe RESTful APIs from a functional perspective. OAS has been a success due to its simple model and the wide ecosystem of tools supporting the SLA-Driven API development lifecycle. Unfortunately, the current OAS scope ignores crucial information for an API such as its Service Level Agreement (SLA). Therefore, in terms of description and management of non-functional information, the disadvantages of not having a standard include the vendor lock-in and prevent the ecosystem to grow and handle extra functional aspects. In this paper, we present SLA4OAI, pioneering in extending OAS not only allowing the specification of SLAs, but also supporting some stages of the SLA-Driven API lifecycle with an open-source ecosystem. Finally, we validate our proposal having modeled 5488 limitations in 148 plans of 35 real-world APIs and show an initial interest from the industry with 600 and 1900 downloads and installs of the SLA Instrumentation Library and the SLA Engine.Ministerio de Economía y Competitividad TIN2015-70560-RMinisterio de Ciencia, Innovación y Universidades RTI2018-101204-B-C21Ministerio de Educación, Cultura y Deporte FPU15/0298

Fostering SLA-Driven API Specifications

Software architecture tendencies are shifting to a microservice paradigm. In this context, RESTful APIs are being established the standard of integration. API designer often identifies two key issues to be competitive in such growing market. On the one hand, the generation of accurate documentation of the behavior and capabilities of the API to promote its usage; on the other hand, the design of a pricing plan that fits into the potential API user’s needs. Besides the increasing number of API modeling alternatives is emerging, there is a lack of proposals on the definition of flexible pricing plans usually contained in the Service Level Agreements (SLAs). In this paper we propose two different modeling techniques for the description of SLA in a RESTful API context: iAgree and SLA4OAI.Ministerio de Economía y Competitividad TIN2015-70560-RJunta de Andalucía P12-TIC-1867Ministerio de Economía y Competitividad TIN2014-53986-RED

Temporal-Awareness in SLAS. Why Should We Be Concerned?

Traditionally, Service Level Agreements have been decomposed in two sets of properties: functionals (what) and non-functionals (how). However, in our opinion, there has been a third key element that has had a minor attention from academy: temporal awareness (when). We believe temporality is a main concern that should be addressed in realistic scenarios. in doing so, this position paper discuss our experience in extending the specification WS-Agreement with a temporal Domain Specific Language; importantly, main aim of the paper is to provoke a debate about the importance of temporality in SLAs

WS-Governance: a Policy Language for SOA Governance

The widespread use of Service Oriented Architectures (SOA) is beginning to create problems derived from the governance of said structures. To date there is not a single effective solution to solve all existing challenges to govern this type of infrastructure. This paper describes the problems encountered when designing a SOA governance solution in a real e-Government scenario. More specifically, we focus on problems related to specification and automated analysis of government policies. We propose a novel SOA governance specification model as a solution to these problems. We have named this model WS-Governance. in order to ease its adoption by SOA practitioners it: i) shares WS-Policy guidelines and is compatible with it, ii) has XML serialization as well as a plain-text one and iii) has a CSP based semantics that provides a precise description as well as facilitating the automation of some editing and WS-Governance related activities such as consistency checking

Fostering a consistent SPL service ecosystem

Nowadays, Software Product Line (SPL) researchers and practi tioners have a diversity of Automated Analysis of Feature Models (AAFM) tools at their disposal. However, only a few applications are compatible between them. This, increases time to market of new applications and hinders application usage by researchers and prac titioners. In this tutorial, we present how we can successfully create an ecosystem of SPL tools that can be integrated to o er a better user experience. Concretely, we will show how to i) easily provide a common REST interface to an SPL analysis tool thus, fostering application integration; ii) automatically o er a web graphical edi tor to interact with the tool, thus, promoting its usage by end users; and, iii) enable the governance of the applications and create a customized portal for pricing plans. Also, we show other bene ts such as the automatic creation of demo sites for review purposes

ELeCTRA: Induced Usage Limitations Calculation in RESTful APIs

As software architecture design is evolving to microservice paradigms, RESTful APIs become the building blocks of applications. In such a scenario, a growing market of APIs is proliferating and developers face the challenges to take advantage of this reality. For example, third-party APIs typically define different usage limitations depending on the purchased Service Level Agreement (SLA) and, consequently, performing a manual analysis of external APIs and their impact in a microservice architecture is a complex and tedious task. In this demonstration paper, we present ELeCTRA, a tool to automate the analysis of induced usage limitations in an API, derived from its usage of external APIs. This tool takes the structural, conversational and SLA specifications of the API, generates a visual dependency graph and translates the problem into a constraint satisfaction optimization problem (CSOP) to obtain the optimal usage limitations.Ministerio de Economía y Competitividad TIN2015-70560-RJunta de Andalucía P12–TIC–1867Ministerio de Economía y Competitividad TIN2014-53986-REDTMinisterio de Educación, Cultura y Deporte FPU15/0298

Governify for APIs: SLA-Driven Ecosystem for API Governance

As software architecture design is evolving to a microservice paradigm, RESTful APIs are being established as the preferred choice to build applications. In such a scenario, there is a shift towards a growing market of APIs where providers offer different service levels with tailored limitations typically based on the cost. In such a context, while there are well-established standards to describe the functional elements of APIs (such as the OpenAPI Specification), having a standard model for Service Level Agreements (SLAs) for APIs may boost an open ecosystem of tools that would represent an improvement for the industry by automating certain tasks during the development. In this paper, we introduce Governify for APIs, an ecosystem of tools aimed to support the user during the SLA-Driven RESTful APIs’ development process. Namely, an SLA Editor, an SLA Engine and an SLA Instrumentation Library. We also present a fully operational SLA-Driven API Gateway built on the top of our ecosystem of tools. To evaluate our proposal, we used three sources for gathering validation feedback: industry, teaching and research.Ministerio de Economía y Competitividad TIN2015- 70560-RMinisterio de Ciencia, Innovación y Universidades RTI2018-101204-B-C21Ministerio de Educación, Cultura y Deporte FPU15/0298

Towards SLA modeling for RESTful APIs

The term of API Economy is becoming increasingly used to describe the change of vision in how APIs can add value to the organizations. Furthermore, a greater automation of RESTful APIs management can suppose a competitive advantage for the company. New proposals are emerging in order to automatize some API governance tasks and increase the ease of use (e.g. generation of code and documentation). Despite that, the non-functional aspects are often addressed in a highly specific manner or even there not exists any solution for an automatic governance. Nevertheless, these properties are already defined in natural language at the Service Level Agreement (SLA) that both customer and provided have established. In this paper, we carry out a study on the *aaS industry and analyze the current both API modeling and SLA modeling proposals in order to identify the open challenges for an automatic RESTful API governance.Ministerio de Economía y Competitividad TIN2015-70560-RMinisterio de Economía y Competitividad P12–TIC-1867Ministerio de Economía y Competitividad TIN2014-53986-RED

Towards SLA-Driven API Gateways

As APIs are becoming popular to build Service-Based Ap- plications (SBA), API Gateways are being increasingly used to facilitate API features management. They o er API management functionalities such as pricing plans support, user authentication, API versioning or response caching. Some parts of the information that an API Gateway needs are already included into a Service Level Agreement (SLA), that providers use to describe the rights and the obligations of involved par- ties in the service. Unfortunately, current API Gateways do not use any SLA representation model nor SLA underlying technology, thereby miss- ing potential opportunities. In this paper we analyze the state of the art to justify the current situation and we identify some research challenges so as to achieve SLA-Driven API Gateways.European CommissionSpanish and the Andalusian R&D&I programs TIN201232273Spanish and the Andalusian R&D&I programs TIC5906Spanish and the Andalusian R&D&I programs P12TIC-1867Spanish and the Andalusian R&D&I programs TIN2014-53986-RED