Click here to close now.




















Welcome!

IBM Cloud Authors: Elizabeth White, Joe Pruitt, Pat Romanski, Carmen Gonzalez, XebiaLabs Blog

Related Topics: Eclipse, Microservices Expo, IBM Cloud

Eclipse: Article

The Case for Single-Purpose Services

Any service that is created needs to have a cleanly defined responsibility

Introduction
Services are useful, but they come with a price tag. The cost of developing a service is higher than the cost of developing a traditional (non-service-oriented) application, primarily due to the extra work and infrastructure required. Another common concern when creating and consuming services is the possibility of a performance hit. Together these issues hint that even if you've decided to wholeheartedly adopt SOA, you may not want or need to move all your functionality into services. This is where the application Service Encapsulation becomes a focal point as we need specific criteria to determine what should and should not be encapsulated into services.

To make this determination, we will take a look at three different aspects:

-- acceptable reasons for creating a service

-- costs associated with creating a service

-- and, of course, the performance issue

After covering these aspects specifically in relation to single-purpose services, I will introduce an implementation strategy.

Reasons to Create a Service
Any service that is created needs to have a cleanly defined responsibility. The capabilities it exposes should clearly fall within this defined responsibility. In the case of a single-purpose service, it can be argued that it may be better to implement single-purpose logic as a non-service-oriented application. Let's take a closer look at some of the more important considerations:

Reuse
When logic is incorporated into a service, it is potentially available for reuse by multiple applications, some of which may themselves be services. Reuse leads to reduced development and maintenance effort, which translates into a lower cost of ownership and can further result in improved quality and lower risks [REF-2]. Reuse is also an important part of the agile IT enterprise. Composing existing logic to solve larger business problems is more efficient than writing all of the logic from scratch.

Alas, enabling this kind of reuse is not as easy as just incorporating logic into services; it often requires a lot of thinking and design effort to create a service that is truly reusable. But, it can be done. With regards to single-purpose services, reuse is usually not a consideration. These services are specific to parent business process logic and therefore serve just that one purpose. Figure 1 illustrates some common service categories [REF-3] and how they relate to each other and business processes.

(Figure 1: A Service Inventory typically consists of services from multiple categories. Process-specific services can not be reused when implementing support for other business processes. The more process-agnostic a service is the higher it's reusability.)

As just stated, services that cannot be repurposed to automate another business process, as per Non-Agnostic Context, are not considered reusable. However, an important realization here is that logic that solves only one large business problem may still be used by multiple consumers.

Let's explore this notion with a simple analogy. Due to technological advances, the manner in which people perform their jobs today is very different compared to 20 years ago and in the years to come we will probably witness an increase in the rate of technological progress. One kind of change that we have seen is that companies want to enable employees to perform their jobs using different tools in different settings. When we are at our desk we typically expect rich functionality and applications that make the best of our hardware, such as advanced large screens with high resolution and many colors and advanced keyboards with many functions, to name but a few.

On the other hand, we want to be able to do at least some of the same tasks when we are traveling and in that setting we may only have access to, say, a Smartphone. This type of mobile device is much more difficult to work with than a desktop application, and it requires a very different kind of user interface. Processing power, development environments and support for frameworks, among other things, are more limited for Smartphone applications. In spite of these differences, the two applications (desktop and mobile) can still be designed to automate the same task (see Figure 2). As a result, both applications could call the same single-purpose service (which actually does lead to a form of reuse).

(Figure 2: Alice, Bob and Carol work for different departments but are responsible for different activities that make up a business process. Some of the process steps need IT support and some don't. Carol owns a desktop application and a smartphone application. She creates a service to encapsulate the process-related logic that she is responsible for and lets her applications call the service.)

Even though reuse is an important criterion for creating a service it is by no means the only one. In a recent blog post [REF-4] Paul C Brown argues that the main criteria for determining if a capability ought to be put inside a service (apart from reuse) are multiple providers and isolation against change. These are discussed briefly below.

Multiple Providers
The reuse of a service can be thought of as the existence of two or more service consumers. The reverse of this is when you have two or more providers of the service

(Figure 3: Reuse compared to multiple providers.)

Choosing between providers, calling multiple providers, or merging together results from different providers might be non-trivial tasks, and applications can be shielded from this kind of logic by placing it inside a service. Corporate mergers and acquisitions often lead to this kind of scenario, but it can also occur within a company when multiple departments work with overlapping tasks and information. Due to the commonality of this situation, there are design patterns available that describe exactly how to construct such services (e.g. Enterprise Domain Repository [REF-5]).

A problem that must be handled when using multiple providers is that of partial failures. As the number of network links and composed services increases, the probability for failure in one of these links or services increases. To address this, a single-purpose service might securely store messages and make a number of retries to accomplish the delivery of messages to composed services, as per Reliable Messaging. Shielding a consumer from these complex tasks is a good enough reason to create a service, even if it cannot be reused.

Isolation Against Change
Being able to handle change successfully is one of the biggest promises of service-orientation. SOA can help us achieve increased business or organizational agility [REF-6] in several ways, one of which is by developing services and consumers in parallel. This approach requires that we (the service and consumer developers) have first have agreed upon the contract.

Another way is to create new functionality by composing existing services, either our own or services provided by someone else. Yet another important aspect is enabling change by limiting the parts that need development effort to bring about the desired changes. This means making sure that when you change something that the change only affects a limited and preferably isolated part of your software assets. All these issues relate to being able to develop new functionality or change existing functionality with less effort and in a shorter period of time.

To be able to quickly adapt to change can be essential for a business. As Jim Webber so eloquently puts it: "Business people are spaghetti-heads" [REF-7]! Behind this statement lies the profound understanding of the fact that business people need to make new decisions - sometimes even unexpected decisions - in the light of new business demands and opportunities.

Changes in a business process can lead to changes in services, consumers, or both, but there are also justifiable reasons for changing a service even when the business process it encapsulates has not changed.

When implementing a service, there are a variety of realization options ranging from buying or building applications hosted on premise via different hosting options and placing services in the cloud to options that haven't even been conceived yet [REF-8]. These ever-evolving options lead to never-ending opportunities for change that are further influenced by the cost associated with the options, your company's business strategy, and many other factors.

One factor worth calling out is the business strategy, because this strategy itself can be subject to change over time. When a company's strategy changes so will the strategic importance of its services and other IT assets. What this means is that outsourcing may become an option for a particular service today (e.g. to cut costs) but it may be then be necessary to in-source it tomorrow when it becomes more strategically significant (Figure 4)

By encapsulating logic into a service, these kinds of changes will become much easier to handle. A single-purpose service might swap out the current implementation of one of it's composed services with an alternative implementation without changing its contract. To be able to accomplish this you may have to apply Data Format Transformation inside the single-purpose service.

(Figure 4: By creating a service that encapsulates single-purpose functionality it becomes possible to quickly outsource or insource functionality - or choose between any of the options in between - without affecting the consumer)

Although it can be tempting to always plan for this kind of flexibility, it is important to keep in mind that agility may not be the most important factor for all processes or companies. Balancing the need for business flexibility in proportion to the cost of IT flexibility can become the true key to success.

More Stories By Herbjorn Wilhelmsen

Herbjorn Wilhelmsen is an Architect and Senior Consultant at Objectware in Stockholm, Sweden. His main focus areas include service-oriented architecture, Web services and business architecture. Herbjörn has many years of industry experience working as a developer, development manager, architect and teacher in several fields of operations, such as telecommunications, marketing, payment industry, health care and public services. He is active as an author in the Prentice Hall Service-Oriented Computing Series from Thomas Erl and has contributed design patterns to SOAPatterns.org. He leads the Business-to-IT group in the Swedish chapter of the International Association of Software Architects, which performs a comparative study of a number of business architecture methodologies. Herbjörn holds a Bachelor of Science from Stockholm University.

@ThingsExpo Stories
The Internet of Everything (IoE) brings together people, process, data and things to make networked connections more relevant and valuable than ever before – transforming information into knowledge and knowledge into wisdom. IoE creates new capabilities, richer experiences, and unprecedented opportunities to improve business and government operations, decision making and mission support capabilities.
The Internet of Things is not only adding billions of sensors and billions of terabytes to the Internet. It is also forcing a fundamental change in the way we envision Information Technology. For the first time, more data is being created by devices at the edge of the Internet rather than from centralized systems. What does this mean for today's IT professional? In this Power Panel at @ThingsExpo, moderated by Conference Chair Roger Strukhoff, panelists addressed this very serious issue of profound change in the industry.
Discussions about cloud computing are evolving into discussions about enterprise IT in general. As enterprises increasingly migrate toward their own unique clouds, new issues such as the use of containers and microservices emerge to keep things interesting. In this Power Panel at 16th Cloud Expo, moderated by Conference Chair Roger Strukhoff, panelists addressed the state of cloud computing today, and what enterprise IT professionals need to know about how the latest topics and trends affect their organization.
SYS-CON Events announced today that HPM Networks will exhibit at the 17th International Cloud Expo®, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. For 20 years, HPM Networks has been integrating technology solutions that solve complex business challenges. HPM Networks has designed solutions for both SMB and enterprise customers throughout the San Francisco Bay Area.
For IoT to grow as quickly as analyst firms’ project, a lot is going to fall on developers to quickly bring applications to market. But the lack of a standard development platform threatens to slow growth and make application development more time consuming and costly, much like we’ve seen in the mobile space. In his session at @ThingsExpo, Mike Weiner, Product Manager of the Omega DevCloud with KORE Telematics Inc., discussed the evolving requirements for developers as IoT matures and conducted a live demonstration of how quickly application development can happen when the need to comply wit...
Explosive growth in connected devices. Enormous amounts of data for collection and analysis. Critical use of data for split-second decision making and actionable information. All three are factors in making the Internet of Things a reality. Yet, any one factor would have an IT organization pondering its infrastructure strategy. How should your organization enhance its IT framework to enable an Internet of Things implementation? In his session at @ThingsExpo, James Kirkland, Red Hat's Chief Architect for the Internet of Things and Intelligent Systems, described how to revolutionize your archit...
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 session at @ThingsExpo, Jason Mondanaro, Director, Product Management at Metanga, discussed how you can plan to cooperate, partner, and form lasting all-star teams to change the world and it starts with business models and monetization strategies.
Converging digital disruptions is creating a major sea change - Cisco calls this the Internet of Everything (IoE). IoE is the network connection of People, Process, Data and Things, fueled by Cloud, Mobile, Social, Analytics and Security, and it represents a $19Trillion value-at-stake over the next 10 years. In her keynote at @ThingsExpo, Manjula Talreja, VP of Cisco Consulting Services, discussed IoE and the enormous opportunities it provides to public and private firms alike. She will share what businesses must do to thrive in the IoE economy, citing examples from several industry sectors.
Growth hacking is common for startups to make unheard-of progress in building their business. Career Hacks can help Geek Girls and those who support them (yes, that's you too, Dad!) to excel in this typically male-dominated world. Get ready to learn the facts: Is there a bias against women in the tech / developer communities? Why are women 50% of the workforce, but hold only 24% of the STEM or IT positions? Some beginnings of what to do about it! In her Opening Keynote at 16th Cloud Expo, Sandy Carter, IBM General Manager Cloud Ecosystem and Developers, and a Social Business Evangelist, d...
There will be 150 billion connected devices by 2020. New digital businesses have already disrupted value chains across every industry. APIs are at the center of the digital business. You need to understand what assets you have that can be exposed digitally, what their digital value chain is, and how to create an effective business model around that value chain to compete in this economy. No enterprise can be complacent and not engage in the digital economy. Learn how to be the disruptor and not the disruptee.
Akana has released Envision, an enhanced API analytics platform that helps enterprises mine critical insights across their digital eco-systems, understand their customers and partners and offer value-added personalized services. “In today’s digital economy, data-driven insights are proving to be a key differentiator for businesses. Understanding the data that is being tunneled through their APIs and how it can be used to optimize their business and operations is of paramount importance,” said Alistair Farquharson, CTO of Akana.
Business as usual for IT is evolving into a "Make or Buy" decision on a service-by-service conversation with input from the LOBs. How does your organization move forward with cloud? In his general session at 16th Cloud Expo, Paul Maravei, Regional Sales Manager, Hybrid Cloud and Managed Services at Cisco, discusses how Cisco and its partners offer a market-leading portfolio and ecosystem of cloud infrastructure and application services that allow you to uniquely and securely combine cloud business applications and services across multiple cloud delivery models.
The enterprise market will drive IoT device adoption over the next five years. In his session at @ThingsExpo, John Greenough, an analyst at BI Intelligence, division of Business Insider, analyzed how companies will adopt IoT products and the associated cost of adopting those products. John Greenough is the lead analyst covering the Internet of Things for BI Intelligence- Business Insider’s paid research service. Numerous IoT companies have cited his analysis of the IoT. Prior to joining BI Intelligence, he worked analyzing bank technology for Corporate Insight and The Clearing House Payment...
In his keynote at 16th Cloud Expo, Rodney Rogers, CEO of Virtustream, discussed the evolution of the company from inception to its recent acquisition by EMC – including personal insights, lessons learned (and some WTF moments) along the way. Learn how Virtustream’s unique approach of combining the economics and elasticity of the consumer cloud model with proper performance, application automation and security into a platform became a breakout success with enterprise customers and a natural fit for the EMC Federation.
"Optimal Design is a technology integration and product development firm that specializes in connecting devices to the cloud," stated Joe Wascow, Co-Founder & CMO of Optimal Design, in this SYS-CON.tv interview at @ThingsExpo, held June 9-11, 2015, at the Javits Center in New York City.
SYS-CON Events announced today that CommVault has been named “Bronze Sponsor” of SYS-CON's 17th International Cloud Expo®, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. A singular vision – a belief in a better way to address current and future data management needs – guides CommVault in the development of Singular Information Management® solutions for high-performance data protection, universal availability and simplified management of data on complex storage networks. CommVault's exclusive single-platform architecture gives companies unp...
Electric Cloud and Arynga have announced a product integration partnership that will bring Continuous Delivery solutions to the automotive Internet-of-Things (IoT) market. The joint solution will help automotive manufacturers, OEMs and system integrators adopt DevOps automation and Continuous Delivery practices that reduce software build and release cycle times within the complex and specific parameters of embedded and IoT software systems.
"ciqada is a combined platform of hardware modules and server products that lets people take their existing devices or new devices and lets them be accessible over the Internet for their users," noted Geoff Engelstein of ciqada, a division of Mars International, in this SYS-CON.tv interview at @ThingsExpo, held June 9-11, 2015, at the Javits Center in New York City.
Internet of Things is moving from being a hype to a reality. Experts estimate that internet connected cars will grow to 152 million, while over 100 million internet connected wireless light bulbs and lamps will be operational by 2020. These and many other intriguing statistics highlight the importance of Internet powered devices and how market penetration is going to multiply many times over in the next few years.
SYS-CON Events announced today that Dyn, the worldwide leader in Internet Performance, will exhibit at SYS-CON's 17th International Cloud Expo®, which will take place on November 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. Dyn is a cloud-based Internet Performance company. Dyn helps companies monitor, control, and optimize online infrastructure for an exceptional end-user experience. Through a world-class network and unrivaled, objective intelligence into Internet conditions, Dyn ensures traffic gets delivered faster, safer, and more reliably than ever.