|By Ron Schmelzer||
|July 17, 2011 03:00 PM EDT||
Many of you know me as one half of the ZapThink team – an advisor, analyst, sometimes-trainer, and pundit that has been focused on XML, web services, service oriented architecture (SOA), and now cloud computing over the past decade or so. Some you may also know that immediately prior to starting ZapThink I was one of the original members of the UDDI Advisory Group back in 2000 when I was with ChannelWave, and I also sat on a number of standards bodies including RosettaNet, ebXML, and CPExchange initiatives. Furthermore, as part of the ZapThink team, I tracked the various WS-* standards from their inception to their current “mature” standing.
I’ve closely followed the ups and downs of the Web Service Interoperability (WS-I) organization and more than a few efforts to standardize such things as business process. Why do I mention all this? To let you know that I’m no slouch when it comes to understanding the full scope and depth of the web services family of standards. And yet, when push came to shove and I was tasked with implementing SOA as a developer, what did I choose? REST.
Representational State Transfer, commonly known as REST, is a style of distributed software architecture that offers an alternative to the commonly accepted XML-based web services as a means for system-to-system interaction. ZapThink has written numerous times about REST and its relationship to SOA and Web Services. Of course, this has nothing to do with Service-Oriented Architecture, as we’ve discussed in numerous ZapFlashes in the past. The power of SOA is in loose coupling, composition, and how it enables approaches like cloud computing. It is for these reasons that I chose to adopt SOA for a project I’m currently working on. But when I needed to implement the services I had already determined were necessary, I faced a choice: use web services or REST-based styles as the means to interact with the services. For the reasons I outline below, REST was a clear winner for my particular use case.
Web services in theory and in practice
The main concepts behind Web Services were established in 1999 and 2000 during the height of the dot-com boom. SOAP, then known as the Simple Object Access Protocol and later just “SOAP,” is the standardized, XML-based method for interacting with a third-party service. Simple in concept, but in practice, there’s many ways to utilize SOAP. RPC style (we think not) or Document style? How do you identify end points? And what about naming operations and methods? Clearly SOAP on its own leaves too much to interpretation.
So, this is the role that the Web Services Description Language (WSDL) is supposed to fill. But writing and reading (and understanding) WSDL is a cumbersome affair. Data type matching can be a pain. Versioning is a bear. Minor server-side changes often result in different WSDL and a resulting different service interface, and on the client-side, XSD descriptions of the service are often similarly tied to a particular version of the SOAP endpoint and can break all too easily. And you still have all the problems associated with SOAP. In my attempts to simply get a service up and running, I found myself fighting more with SOAP and WSDL than doing actual work to get services built and systems communicating.
The third “leg” of the web services concept, Universal Description, Discovery and Integration (UDDI), conceptually makes a lot of sense, but in practice, hardly anyone uses it. As a developer, I couldn’t even think of a scenario where UDDI would help me in my particular project. Sure, I could artificially insert UDDI into my use case, but in the scenario where I needed loose coupling, I could get that by simply abstracting my end points and data schema. To the extent I needed run-time and design-time discoverability or visibility into services at various different states of versioning, I could make use of a registry / repository without having to involve UDDI at all. I think UDDI’s time has come and gone, and the market has proven its lack of necessity. Bye, bye UDDI.
As for the rest of the WS-* stack, these standards are far too undeveloped, under implemented, under-standardized, inefficient, and obscure to make any use of whatever value they might bring to the SOA equation, with a few select exceptions. I have found the security-related specifications, specifically OAuth, Service Provisioning Markup Language (SPML), Security Assertion Markup Language (SAML), eXtensible Access Control Markup Language (XACML), are particularly useful, especially in a Cloud environment. These specifications are not web services dependent, and indeed, many of the largest Web-based applications use OAuth and the other specs to make their REST-based environments more secure.
Why REST is ruling
But even more than the simplicity, I appreciated the elegance of the REST approach. The basic operation and scalability of the Web has proven the underlying premise of the fundamental REST approach. HTTP operations are standardized, widely accepted, well understood, and operate consistently. There’s no need for a REST version of the WS-I. There’s no need to communicate company-specific SOAP actions or methods – the basic GET, POST, PUT, and DELETE operations are standardized across all Service calls.
Even more appealing is the fact that the vendors have not polluted REST with their own interests. The primary driver for web services adoption has been the vendors. Say what you might about the standard’s applicability outside a vendor environment, one would be very hard pressed to utilize web services in any robust way without first choosing a vendor platform. And once you’ve chosen that platform, you’ve pretty much committed to a specific web services implementation approach, forcing third-parties and others to comply with the quirks of your particular platform.
Not so with REST. Not only does the simplicity and purity of the approach eschew vendor meddling, it actually negates much of the value that vendor offerings provide. Indeed, it’s much easier (and not to mention lower cost) to utilize open source offerings in REST-based SOA approaches than more expensive and cumbersome vendor offerings. Furthermore, you can leverage existing technologies that have already proven themselves in high-scale, high-performance environments.
Focus on architecture, not on HTTP
So, how did I meld the fundamental tenets of SOA with a REST-based implementation approach? In our Web-Oriented SOA ZapFlash, we recommended using the following approach to RESTafarian styles of SOA:
- Make sure your services are properly abstracted, loosely coupled, composable, and contracted
- Every web-oriented service should have an unambiguous and unique URI to locate the service on the network
- Use the URI as a means to locate as well as taxonomically define the service in relation to other services.
- Use well-established actions (such as POST, GET, PUT, and DELETE for HTTP) for interacting with services
- Lessen the dependence on proprietary middleware to coordinate service interaction and shift to common web infrastructure to handle SOA infrastructure needs
Much of the criticism of REST comes not from the interaction approach, but rather from the use of HTTP. Roy Fielding, the progenitor of REST, states in his dissertation that REST was initially described in the context of HTTP, but is not limited to that protocol. He states that REST is an architectural style, not an implementation, and that the web and the use of the HTTP protocol happens to be designed under such style. I chose to implement REST using eXtensible Messaging and Presence Protocol (XMPP) as a way of doing distributed, asynchronous messaging styles of REST-based Service interaction. XMPP, also known as the Jabber Protocol, has already proven itself as a widely-used, highly-scalable messaging protocol for secure and distributed near-realtime messaging protocol. XMPP-based software is deployed widely across the Internet, and forms the basis of many high-scale messaging systems, including those used by Facebook and Google.
Am I bending the rules or the intent of REST by using XMPP instead of HTTP? Perhaps. If HTTP suits you, then you have a wide array of options to choose from in optimizing your implementation. Steven Tilkov does a good job of describing how to best apply HTTP for REST use. But you don’t have to choose XMPP for your implementation if HTTP doesn’t meet your needs. There are a number of other open-source approaches to alternative transports for REST existing including RabbitMQ (based on the AMQP standard), ZeroMQ, and Redis.
The ZapThink take
The title of this ZapFlash is a bit of a misnomer. In order to be a convert to something you first need to be indoctrinated into another religion, and I don’t believe that REST or web services is something upon which to take a religious stance. That being said, for the past decade or so, dogmatic vendors, developers, and enterprise architects have reinforced the notion that to do SOA properly, you must use web services.
ZapThink never believed that this was the case, and my own experiences now shows that SOA can be done well in practice without using Web Services in any significant manner. Indeed, my experience shows that it is actually easier, less costly, and potentially more scalable to not use Web Services unless there’s an otherwise compelling reason.
The conversation about SOA is a conversation about architecture – everything that we’ve talked about over the past decade applies just as equally when the Services are implemented using REST or Web Services on top of any protocol, infrastructure, or data schema. While good enterprise architects do their work at the architecture level of abstraction, the implementation details are left to those who are most concerned with putting the principles of SOA into practice.
You may also be interested in:
Lots of cloud technology predictions and analysis are still dealing with future spending and planning, but there are plenty of real-world cloud use cases and implementations happening now. One approach, taken by stalwart GE, is to use SaaS applications for non-differentiated uses. For them, that means moving functions like HR, finance, taxes and scheduling to SaaS, while spending their software development time and resources on the core apps that make GE better, such as inventory, planning and s...
Mar. 29, 2017 06:45 PM EDT Reads: 915
DevOps is often described as a combination of technology and culture. Without both, DevOps isn't complete. However, applying the culture to outdated technology is a recipe for disaster; as response times grow and connections between teams are delayed by technology, the culture will die. A Nutanix Enterprise Cloud has many benefits that provide the needed base for a true DevOps paradigm. In his Day 3 Keynote at 20th Cloud Expo, Chris Brown, a Solutions Marketing Manager at Nutanix, will explore t...
Mar. 29, 2017 04:00 PM EDT Reads: 3,224
The IT industry is undergoing a significant evolution to keep up with cloud application demand. We see this happening as a mindset shift, from traditional IT teams to more well-rounded, cloud-focused job roles. The IT industry has become so cloud-minded that Gartner predicts that by 2020, this cloud shift will impact more than $1 trillion of global IT spending. This shift, however, has left some IT professionals feeling a little anxious about what lies ahead. The good news is that cloud computin...
Mar. 29, 2017 03:15 PM EDT Reads: 1,614
As Enterprise business moves from Monoliths to Microservices, adoption and successful implementations of Microservices become more evident. The goal of Microservices is to improve software delivery speed and increase system safety as scale increases. Documenting hurdles and problems for the use of Microservices will help consultants, architects and specialists to avoid repeating the same mistakes and learn how and when to use (or not use) Microservices at the enterprise level. The circumstance w...
Mar. 29, 2017 03:00 PM EDT Reads: 4,452
SYS-CON Events announced today that Auditwerx will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Auditwerx specializes in SOC 1, SOC 2, and SOC 3 attestation services throughout the U.S. and Canada. As a division of Carr, Riggs & Ingram (CRI), one of the top 20 largest CPA firms nationally, you can expect the resources, skills, and experience of a much larger firm combined with the accessibility and attent...
Mar. 29, 2017 02:30 PM EDT Reads: 781
SYS-CON Events announced today that HTBase will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. HTBase (Gartner 2016 Cool Vendor) delivers a Composable IT infrastructure solution architected for agility and increased efficiency. It turns compute, storage, and fabric into fluid pools of resources that are easily composed and re-composed to meet each application’s needs. With HTBase, companies can quickly prov...
Mar. 29, 2017 02:15 PM EDT Reads: 3,325
Everyone wants to use containers, but monitoring containers is hard. New ephemeral architecture introduces new challenges in how monitoring tools need to monitor and visualize containers, so your team can make sense of everything. In his session at @DevOpsSummit, David Gildeh, co-founder and CEO of Outlyer, will go through the challenges and show there is light at the end of the tunnel if you use the right tools and understand what you need to be monitoring to successfully use containers in your...
Mar. 29, 2017 01:45 PM EDT Reads: 1,977
What if you could build a web application that could support true web-scale traffic without having to ever provision or manage a single server? Sounds magical, and it is! In his session at 20th Cloud Expo, Chris Munns, Senior Developer Advocate for Serverless Applications at Amazon Web Services, will show how to build a serverless website that scales automatically using services like AWS Lambda, Amazon API Gateway, and Amazon S3. We will review several frameworks that can help you build serverle...
Mar. 29, 2017 01:30 PM EDT Reads: 2,296
Buzzword alert: Microservices and IoT at a DevOps conference? What could possibly go wrong? In this Power Panel at DevOps Summit, moderated by Jason Bloomberg, the leading expert on architecting agility for the enterprise and president of Intellyx, panelists peeled away the buzz and discuss the important architectural principles behind implementing IoT solutions for the enterprise. As remote IoT devices and sensors become increasingly intelligent, they become part of our distributed cloud enviro...
Mar. 29, 2017 12:15 PM EDT Reads: 7,969
@DevOpsSummit has been named the ‘Top DevOps Influencer' by iTrend. iTrend processes millions of conversations, tweets, interactions, news articles, press releases, blog posts - and extract meaning form them and analyzes mobile and desktop software platforms used to communicate, various metadata (such as geo location), and automation tools. In overall placement, @DevOpsSummit ranked as the number one ‘DevOps Influencer' followed by @CloudExpo at third, and @MicroservicesE at 24th.
Mar. 29, 2017 10:45 AM EDT Reads: 10,532
By now, every company in the world is on the lookout for the digital disruption that will threaten their existence. In study after study, executives believe that technology has either already disrupted their industry, is in the process of disrupting it or will disrupt it in the near future. As a result, every organization is taking steps to prepare for or mitigate unforeseen disruptions. Yet in almost every industry, the disruption trend continues unabated.
Mar. 29, 2017 09:00 AM EDT Reads: 961
In his General Session at 16th Cloud Expo, David Shacochis, host of The Hybrid IT Files podcast and Vice President at CenturyLink, investigated three key trends of the “gigabit economy" though the story of a Fortune 500 communications company in transformation. Narrating how multi-modal hybrid IT, service automation, and agile delivery all intersect, he will cover the role of storytelling and empathy in achieving strategic alignment between the enterprise and its information technology.
Mar. 29, 2017 08:00 AM EDT Reads: 7,600
While DevOps most critically and famously fosters collaboration, communication, and integration through cultural change, culture is more of an output than an input. In order to actively drive cultural evolution, organizations must make substantial organizational and process changes, and adopt new technologies, to encourage a DevOps culture. Moderated by Andi Mann, panelists discussed how to balance these three pillars of DevOps, where to focus attention (and resources), where organizations might...
Mar. 29, 2017 06:30 AM EDT Reads: 6,297
Microservices are a very exciting architectural approach that many organizations are looking to as a way to accelerate innovation. Microservices promise to allow teams to move away from monolithic "ball of mud" systems, but the reality is that, in the vast majority of organizations, different projects and technologies will continue to be developed at different speeds. How to handle the dependencies between these disparate systems with different iteration cycles? Consider the "canoncial problem" ...
Mar. 29, 2017 06:00 AM EDT Reads: 9,116
In his session at 20th Cloud Expo, Scott Davis, CTO of Embotics, will discuss how automation can provide the dynamic management required to cost-effectively deliver microservices and container solutions at scale. He will discuss how flexible automation is the key to effectively bridging and seamlessly coordinating both IT and developer needs for component orchestration across disparate clouds – an increasingly important requirement at today’s multi-cloud enterprise.
Mar. 29, 2017 06:00 AM EDT Reads: 2,913
The essence of cloud computing is that all consumable IT resources are delivered as services. In his session at 15th Cloud Expo, Yung Chou, Technology Evangelist at Microsoft, demonstrated the concepts and implementations of two important cloud computing deliveries: Infrastructure as a Service (IaaS) and Platform as a Service (PaaS). He discussed from business and technical viewpoints what exactly they are, why we care, how they are different and in what ways, and the strategies for IT to transi...
Mar. 29, 2017 05:00 AM EDT Reads: 6,498
Thanks to Docker and the DevOps revolution, microservices have emerged as the new way to build and deploy applications — and there are plenty of great reasons to embrace the microservices trend. If you are going to adopt microservices, you also have to understand that microservice architectures have many moving parts. When it comes to incident management, this presents an important difference between microservices and monolithic architectures. More moving parts mean more complexity to monitor an...
Mar. 29, 2017 04:30 AM EDT Reads: 3,502
All organizations that did not originate this moment have a pre-existing culture as well as legacy technology and processes that can be more or less amenable to DevOps implementation. That organizational culture is influenced by the personalities and management styles of Executive Management, the wider culture in which the organization is situated, and the personalities of key team members at all levels of the organization. This culture and entrenched interests usually throw a wrench in the work...
Mar. 29, 2017 04:00 AM EDT Reads: 3,277
The Internet of Things is clearly many things: data collection and analytics, wearables, Smart Grids and Smart Cities, the Industrial Internet, and more. Cool platforms like Arduino, Raspberry Pi, Intel's Galileo and Edison, and a diverse world of sensors are making the IoT a great toy box for developers in all these areas. In this Power Panel at @ThingsExpo, moderated by Conference Chair Roger Strukhoff, panelists discussed what things are the most important, which will have the most profound e...
Mar. 29, 2017 04:00 AM EDT Reads: 15,168
DevOps is often described as a combination of technology and culture. Without both, DevOps isn't complete. However, applying the culture to outdated technology is a recipe for disaster; as response times grow and connections between teams are delayed by technology, the culture will die. A Nutanix Enterprise Cloud has many benefits that provide the needed base for a true DevOps paradigm.
Mar. 29, 2017 01:15 AM EDT Reads: 2,590