Welcome!

@CloudExpo Authors: Elizabeth White, Liz McMillan, Scott Sobhani, Pat Romanski, Sanjay Zalavadia

Related Topics: Microservices Expo, Java IoT, Linux Containers, Open Source Cloud, @CloudExpo, SDN Journal

Microservices Expo: Article

Beyond REST and SOA: Introducing Agent-Oriented Architecture

Dynamic coupling represents a paradigm shift in how to build and utilize APIs

A question we commonly get at EnterpriseWeb is whether our platform follows REST or not. Representational State Transfer (REST) is an architectural style for distributed hypermedia systems such as the World Wide Web, and is perhaps best known for providing a lightweight, uniform Web-style application programming interface (API) to server-based resources. One the one hand, EnterpriseWeb can both consume and expose any type of interface, including tightly coupled APIs, Web Services, as well as RESTful APIs, and the platform has no requirement that customers must build distributed hypermedia systems. It would be easy to conclude, therefore, that while EnterpriseWeb supports REST, it is not truly RESTful.

Such a conclusion, however, would neglect the broader architectural context for EnterpriseWeb. The platform builds on top of and extends REST as the foundation for the dynamic, enterprise-class architectural style we call Agent-Oriented Architecture (AOA). EnterpriseWeb's intelligent agent, SmartAlex, leverages RESTful constraints as part of the core functionality of the EnterpriseWeb platform. The resulting AOA pattern essentially reinvents application functionality and enterprise integration, heralding a new paradigm for distributed computing.

The Limitations of REST
One of the primary challenges to the successful application of REST is understanding how to extend REST to distributed hypermedia systems in general, beyond the straightforward interactions between browsers and Web servers. To help clarify this point, Figure 1 below illustrates a simple RESTful architecture. In this example, the client is a browser, and it sends GETs and PUTs or other RESTful queries to URIs that resolve to resources on a server, which responds by sending the appropriate representation back to the client. In addition, REST allows for a cache intermediating between client and server that might resolve queries on behalf of the server for scalability purposes.

Figure 1: Simple RESTful Architecture

As an architectural style, however, the point of REST isn't the uniform interface that the HTTP verbs enable. REST is really about hypermedia, where hypermedia are the engine of application state - the HATEOAS constraint essential to building hypermedia systems. In figure 1, we're representing HATEOAS by the interactions between human users and their browsers as people click links on Web pages, thus advancing the application state. The RESTful client (in other words, the browser) maintains application state for each user by showing them the Web page (or other representation) they requested when they followed a given hyperlink.

However, software clients that do not necessarily have user interfaces may be problematic for REST, but they are a familiar part of the Service-Oriented Architecture (SOA) architectural style, where we call such clients Service consumers. Combining REST and SOA into the combined architectural style we call REST-Based SOA introduces the notion of an intermediary that presents a Service endpoint and resolves interactions with that endpoint into underlying interactions with various legacy systems. The SOA intermediary in this case exposes RESTful endpoints as URIs that accept GETs, PUTs, etc. from Service consumers, which can be any software client. See figure 2 below for an illustration of the REST-Based SOA pattern.

Figure 2: REST-Based SOA

Note that adding SOA to REST augments the role of the intermediary. Pure REST allows for simple caching and proxy behavior, while SOA calls for policy-based routing and transformation operations that provide the Service abstraction. SOA also reinforces the notion that the Service consumer can be any piece of software, regardless of whether it has a user interface.

Even with REST-based SOA, however, we still have problems with implementing HATEOAS: coding our clients so that they are able to gather the metadata they need by following hyperlinks. In other words, how do we apply REST to any hypermedia system, where instead of a browser we have any piece of software as a client? How do we code the software client to know how to follow hyperlinks, where it doesn't know what the hyperlinks are ahead of time or what representations they're supposed to interact with? Humans simply click hyperlinks until they get the representation they want, even if they don't know beforehand how to find it. How do we teach software to automate this process and gather all the metadata it needs by following a sequence of hyperlinks?

Introducing Agent-Oriented Architecture
The answer to these questions is to cast an intelligent agent in the role of SOA intermediary in the REST-Based SOA pattern in Figure 2. Intelligent software agents (or simply intelligent agents when we know we're talking about software) are autonomous programs that have the authority to determine what action is appropriate based upon the requests made of them. In this new, Agent-Oriented architectural pattern, the agent interacts with any resource as a RESTful client, where the agent must be able to automatically follow hyperlinks to gather all the information it requires in order to respond appropriately to any request from the client.

In other words, when following this newly coined AOA architectural style, software clients do not have to comply with HATEOAS (they may, but such compliance is optional). Instead, the agent alone must follow the HATEOAS constraint as it interacts with resources. To achieve this behavior, we must underspecify the intelligent agent. In other words, the agent can't know ahead of time what it's supposed to do to respond to any particular request. Instead, it must be able to process any request on demand by fetching related resources that provide the appropriate metadata, data, or code it needs to properly respond to that request with a custom response, for each interaction in real time. Figure 3 below illustrates the basic AOA pattern.

Figure 3: Agent-Oriented Architecture

For each request from any client, regardless of whether it has a user interface, the agent constructs a custom response based on latest and most relevant information available. In fact, requests to the agent can come from anywhere (i.e., they follow an event-driven pattern). The agent's underspecification means that it doesn't know ahead of time what behavior it must exhibit, but it does know how to find the information it needs in order to determine that behavior - and it does that by following hyperlinks, as per HATEOAS. In other words, the goal-oriented agent resolves URIs recursively in order to gather and execute the information it needs - a particularly concise example of fully automated HATEOAS in action.

The Benefits of AOA

An earlier Loosely-Coupled newsletter explained that if you follow REST, you're unable to accept out-of-band metadata or business context outside of the hypermedia. Agent-Oriented Architecture, however, solves these problems, because the agent is free to fetch whatever it needs to complete the request, since it treats all entities - metadata, data, code, etc. - as resources. In other words, the agent serves as a RESTful client, even when the software client does not. What was out-of-band for REST isn't out-of-band for AOA. Everything is on the table.

The true power of AOA, though, lies in how it resolves the fundamental challenge of static APIs. Whether they be Web Services, RESTful APIs, or some other type of loosely-coupled interface, every approach to software integration today suffers from the fact that interactions tend to break when API contract metadata change.

By adding an intelligent agent to the mix, we're able to resolve differences in interaction context between disparate software endpoints dynamically and in real time. Far more than a traditional broker, which must rely on static transformation logic to resolve endpoint differences, the agent must be able to interpret metadata, as well as policies, rules, and the underlying data themselves to create real time interactions that maintain the business context - an example of dynamic coupling, a central principle to AOA.

Dynamic coupling, therefore, represents a paradigm shift in how to build and utilize APIs. Up to this point in time, the focus of both SOA and REST has been on building loosely-coupled interfaces: static, contracted interfaces specified by WSDL and various policy metadata when those interfaces are Web Services, or Internet Media Types and related metadata for RESTful interactions. Neither approach deals well with change. AOA, in contrast, relies upon dynamic coupling that responds automatically to change, since the agent interprets current metadata for every interaction in real time.

Icons by http://dryicons.com

More Stories By Jason Bloomberg

Jason Bloomberg is the leading expert on architecting agility for the enterprise. As president of Intellyx, Mr. Bloomberg brings his years of thought leadership in the areas of Cloud Computing, Enterprise Architecture, and Service-Oriented Architecture to a global clientele of business executives, architects, software vendors, and Cloud service providers looking to achieve technology-enabled business agility across their organizations and for their customers. His latest book, The Agile Architecture Revolution (John Wiley & Sons, 2013), sets the stage for Mr. Bloomberg’s groundbreaking Agile Architecture vision.

Mr. Bloomberg is perhaps best known for his twelve years at ZapThink, where he created and delivered the Licensed ZapThink Architect (LZA) SOA course and associated credential, certifying over 1,700 professionals worldwide. He is one of the original Managing Partners of ZapThink LLC, the leading SOA advisory and analysis firm, which was acquired by Dovel Technologies in 2011. He now runs the successor to the LZA program, the Bloomberg Agile Architecture Course, around the world.

Mr. Bloomberg is a frequent conference speaker and prolific writer. He has published over 500 articles, spoken at over 300 conferences, Webinars, and other events, and has been quoted in the press over 1,400 times as the leading expert on agile approaches to architecture in the enterprise.

Mr. Bloomberg’s previous book, Service Orient or Be Doomed! How Service Orientation Will Change Your Business (John Wiley & Sons, 2006, coauthored with Ron Schmelzer), is recognized as the leading business book on Service Orientation. He also co-authored the books XML and Web Services Unleashed (SAMS Publishing, 2002), and Web Page Scripting Techniques (Hayden Books, 1996).

Prior to ZapThink, Mr. Bloomberg built a diverse background in eBusiness technology management and industry analysis, including serving as a senior analyst in IDC’s eBusiness Advisory group, as well as holding eBusiness management positions at USWeb/CKS (later marchFIRST) and WaveBend Solutions (now Hitachi Consulting).

@CloudExpo Stories
More and more companies are looking to microservices as an architectural pattern for breaking apart applications into more manageable pieces so that agile teams can deliver new features quicker and more effectively. What this pattern has done more than anything to date is spark organizational transformations, setting the foundation for future application development. In practice, however, there are a number of considerations to make that go beyond simply “build, ship, and run,” which changes ho...
"Avere Systems is a hybrid cloud solution provider. We have customers that want to use cloud storage and we have customers that want to take advantage of cloud compute," explained Rebecca Thompson, VP of Marketing at Avere Systems, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
A strange thing is happening along the way to the Internet of Things, namely far too many devices to work with and manage. It has become clear that we'll need much higher efficiency user experiences that can allow us to more easily and scalably work with the thousands of devices that will soon be in each of our lives. Enter the conversational interface revolution, combining bots we can literally talk with, gesture to, and even direct with our thoughts, with embedded artificial intelligence, wh...
The IoT is changing the way enterprises conduct business. In his session at @ThingsExpo, Eric Hoffman, Vice President at EastBanc Technologies, discussed how businesses can gain an edge over competitors by empowering consumers to take control through IoT. He cited examples such as a Washington, D.C.-based sports club that leveraged IoT and the cloud to develop a comprehensive booking system. He also highlighted how IoT can revitalize and restore outdated business models, making them profitable ...
Machine Learning helps make complex systems more efficient. By applying advanced Machine Learning techniques such as Cognitive Fingerprinting, wind project operators can utilize these tools to learn from collected data, detect regular patterns, and optimize their own operations. In his session at 18th Cloud Expo, Stuart Gillen, Director of Business Development at SparkCognition, discussed how research has demonstrated the value of Machine Learning in delivering next generation analytics to imp...
The cloud market growth today is largely in public clouds. While there is a lot of spend in IT departments in virtualization, these aren’t yet translating into a true “cloud” experience within the enterprise. What is stopping the growth of the “private cloud” market? In his general session at 18th Cloud Expo, Nara Rajagopalan, CEO of Accelerite, explored the challenges in deploying, managing, and getting adoption for a private cloud within an enterprise. What are the key differences between wh...
Creating replica copies to tolerate a certain number of failures is easy, but very expensive at cloud-scale. Conventional RAID has lower overhead, but it is limited in the number of failures it can tolerate. And the management is like herding cats (overseeing capacity, rebuilds, migrations, and degraded performance). Download Slide Deck: ▸ Here In his general session at 18th Cloud Expo, Scott Cleland, Senior Director of Product Marketing for the HGST Cloud Infrastructure Business Unit, discusse...
University of Colorado Athletics has selected FORTRUST, Colorado’s only Tier III Gold certified data center, as their official data center and colocation services provider, FORTRUST announced today. A nationally recognized and prominent collegiate athletics program, CU provides a high quality and comprehensive student-athlete experience. The program sponsors 17 varsity teams and in their history, the Colorado Buffaloes have collected an impressive 28 national championships. Maintaining uptime...
It's easy to assume that your app will run on a fast and reliable network. The reality for your app's users, though, is often a slow, unreliable network with spotty coverage. What happens when the network doesn't work, or when the device is in airplane mode? You get unhappy, frustrated users. An offline-first app is an app that works, without error, when there is no network connection. In his session at 18th Cloud Expo, Bradley Holt, a Developer Advocate with IBM Cloud Data Services, discussed...
Connected devices and the industrial internet are growing exponentially every year with Cisco expecting 50 billion devices to be in operation by 2020. In this period of growth, location-based insights are becoming invaluable to many businesses as they adopt new connected technologies. Knowing when and where these devices connect from is critical for a number of scenarios in supply chain management, disaster management, emergency response, M2M, location marketing and more. In his session at @Th...
The pace of innovation, vendor lock-in, production sustainability, cost-effectiveness, and managing risk… In his session at 18th Cloud Expo, Dan Choquette, Founder of RackN, discussed how CIOs are challenged finding the balance of finding the right tools, technology and operational model that serves the business the best. He also discussed how clouds, open source software and infrastructure solutions have benefits but also drawbacks and how workload and operational portability between vendors ...
Dialogic has announced that ZVRS chose Dialogic® PowerMedia™ XMS software media server as part of its latest video relay and translation service offering. ZVRS uses Dialogic’s PowerMedia XMS technology to provide a robust solution that supports a broad range of legacy devices and any-to-any video capabilities with its flagship Z70 videophone. ZVRS selected Dialogic’s solution to facilitate a release of Z70 that met its stringent requirements for legacy device support (H.263 and H.264) with high...
The initial debate is over: Any enterprise with a serious commitment to IT is migrating to the cloud. But things are not so simple. There is a complex mix of on-premises, colocated, and public-cloud deployments. In this power panel at 18th Cloud Expo, moderated by Conference Chair Roger Strukhoff, Randy De Meno, Chief Technologist - Windows Products and Microsoft Partnerships at Commvault; Dave Landa, Chief Operating Officer at kintone; William Morrish, General Manager Product Sales at Interou...
Predictive analytics tools monitor, report, and troubleshoot in order to make proactive decisions about the health, performance, and utilization of storage. Most enterprises combine cloud and on-premise storage, resulting in blended environments of physical, virtual, cloud, and other platforms, which justifies more sophisticated storage analytics. In his session at 18th Cloud Expo, Peter McCallum, Vice President of Datacenter Solutions at FalconStor, discussed using predictive analytics to mon...
Basho Technologies has announced the latest release of Basho Riak TS, version 1.3. Riak TS is an enterprise-grade NoSQL database optimized for Internet of Things (IoT). The open source version enables developers to download the software for free and use it in production as well as make contributions to the code and develop applications around Riak TS. Enhancements to Riak TS make it quick, easy and cost-effective to spin up an instance to test new ideas and build IoT applications. In addition to...
What does it look like when you have access to cloud infrastructure and platform under the same roof? Let’s talk about the different layers of Technology as a Service: who cares, what runs where, and how does it all fit together. In his session at 18th Cloud Expo, Phil Jackson, Lead Technology Evangelist at SoftLayer, an IBM company, spoke about the picture being painted by IBM Cloud and how the tools being crafted can help fill the gaps in your IT infrastructure.
Apixio Inc. has raised $19.3 million in Series D venture capital funding led by SSM Partners with participation from First Analysis, Bain Capital Ventures and Apixio’s largest angel investor. Apixio will dedicate the proceeds toward advancing and scaling products powered by its cognitive computing platform, further enabling insights for optimal patient care. The Series D funding comes as Apixio experiences strong momentum and increasing demand for its HCC Profiler solution, which mines unstruc...
Digital Initiatives create new ways of conducting business, which drive the need for increasingly advanced security and regulatory compliance challenges with exponentially more damaging consequences. In the BMC and Forbes Insights Survey in 2016, 97% of executives said they expect a rise in data breach attempts in the next 12 months. Sixty percent said operations and security teams have only a general understanding of each other’s requirements, resulting in a “SecOps gap” leaving organizations u...
IoT offers a value of almost $4 trillion to the manufacturing industry through platforms that can improve margins, optimize operations & drive high performance work teams. By using IoT technologies as a foundation, manufacturing customers are integrating worker safety with manufacturing systems, driving deep collaboration and utilizing analytics to exponentially increased per-unit margins. However, as Benoit Lheureux, the VP for Research at Gartner points out, “IoT project implementers often ...
It is one thing to build single industrial IoT applications, but what will it take to build the Smart Cities and truly society changing applications of the future? The technology won’t be the problem, it will be the number of parties that need to work together and be aligned in their motivation to succeed. In his Day 2 Keynote at @ThingsExpo, Henrik Kenani Dahlgren, Portfolio Marketing Manager at Ericsson, discussed how to plan to cooperate, partner, and form lasting all-star teams to change t...