Archive for the ‘mashup’ Tag

SOA in Good Eternal Company

graveyard-689x407There’s a place where good acronyms go to die.  I call it the GAG (Good Acronym Graveyard).  It’s a dark foreboding place where over-hyped acronyms lie interred separated from their perfectly valid and useful living legacies.

Terminal Terminology

The first GAG funeral that I witnessed in my career personally was Artificial Intelligence.  In the 80s and early 90s, AI was hyped to the point where our brains would surely atrophy as expert systems, neural networks, fuzzy sets, and other goodies would put homo-sapiens out of business.  AI would be the computing industry’s super hero of the era.  But just as most of our super heroes eventually disappoint as they fail to live up to impossible expectations, AI came crashing down.  So many companies and investors were burnt in the process that the term itself became a pariah.  A proposal or business plan could promise to cure cancer, but would be rejected out of hand if it included the term “AI”.

In reality, the AI funeral was for the term itself.  The living legacy of AI is all around us.  We have automated decisioning and diagnostic systems that use many expert systems concepts.  Rule based systems are widely used to codify business policies, determine insurance quotes, and manage the complexities of telecommunications billing.  Neural networks among other techniques are used in pattern analyses such as facial recognition and linguistics.  Just about every complex search technique in use today owes its roots to a university AI lab.  More generally, heuristic algorithms are now pervasive in everything from music recommendations to counter terrorism.

The principles and techniques of AI have been staggeringly successful, but the over-hyped term and its unreasonable expectations rest in peace in the GAG.  This was no time for sorrow, however.  With this burial went the wasteful distraction of trying to satisfy the insatiable.  Released from this burden, practitioners were free to focus and produce the awesome results that have transformed large tracts of the computing landscape.

So Soon SOA

Service Oriented Architecture or SOA has now entered the GAG.  Following a similar pattern as AI, there is nothing wrong with its principles.  In fact, SOA is exactly the transformative movement required by complex enterprises that require breakthrough advances in agility while avoiding the infeasible cost and limitations of wholesale legacy replacement.  Over the past several years, however, the term SOA has been over-hyped as a silver bullet, a specific technology, or a turnkey solution depending on the agenda of the “hyper”.  To these expectations, SOA must and has failed.

In a 01-05-2009 post entitled “SOA is Dead; Long Live Services“, Anne Thomas Manes writes the following insightful obituary:

SOA met its demise on January 1, 2009, when it was wiped out by the catastrophic impact of the economic recession.  SOA is survived by its offspring: mashups, BPM, SaaS, Cloud Computing, and all other architectural approaches that depend on “services”.

SOA is a strategy and an architecture (people tend to forget that’s what the “A” stands for).  It is a path to which enterprises must commit and in which they must invest in order to realize the returns.  When a project is framed as full blown “SOA”, compelling returns on investment are exceedingly difficult to devise and sell.  However, Software as a Service (SaaS) has gained acceptance as an agile, cost effective alternative to wide-scale software installation and maintenance.  Cloud computing is rapidly ascending to acceptance as a nimble alternative to sizing data centers to handle peak-plus demands.  Mashups are everywhere from grass-roots developers to the enterprise back office.  As these mindset changes continue to cure, the principles of SOA will flourish – even better without the baggage of the term itself.

Requiem

And so we gather together on this cold day in January of 2009 to lay to rest the body of SOA, but not its spirit.  We do not mourn this passing as untimely or empty.  Rather we rejoice in the opportunity to move past empty promises and impossible expectations.

Perhaps now that the GAG is sporting yet another tombstone, we can attend to the real business of enterprise transformation through service orientation.  Perhaps we can even throw in a little AI for good measure… D’OH!!!

Advertisements

Taxonomy for Web Service Sources

Various taxonomies for web services are possible.  A focus on technology might produce classifications such as transport (e.g., HTTP, JMS), representation (e.g., SOAP, REST), response handling (e.g., blocking, asynchronous via polling, asynchronous via callback).  A focus on purpose might look more like data source vs. computational vs. legacy API exposure.

In the Web 2.0+ era, web services are proliferating wildly.  The mashup community is providing huge demand satisfied in part by sites such as ProgrammableWeb where over 1,000 web services can be found, and increasingly online services are opening their platforms via APIs.  Enterprise level SOA (Service Oriented Architecture) initiatives, while slowed by a slowing economy, are also beginning to consume external services as well as exposing their own services for internal use.

In recognition of this proliferation, I believe a new taxonomy is required that addresses the source of services from the perspective of the user, orthogonal to technology or purpose.  By “user” in this context, I am referring to the human developer of any application that consumes web services.

Source Taxonomy

The figure illustrates a draft web service taxonomy where services are classified by the nature of their sources or providers as seen by potential users.

ws-source-taxonomy

Classification:  Ownership

Ownership is the distinction between services that are sourced within the user’s organization (e.g., company, business unit) versus those sourced by parties unaffiliated with their organization.

Internal:  “Services sourced within the user’s organization implying some potential for control over their implementation.”  Examples include web service APIs to internal legacy systems as part of a SOA project.

External:  “Services sourced independent of the user’s organization.”  Examples include information services (e.g., news, market quotes, credit report) and APIs to platforms like Twitter or SalesForce.

Classification:  Provision

Provisioning refers to the relationship between the entity supporting the web service endpoint from the user’s perspective (i.e., the provider) and the entity that supplies the functional implementation of the web service (i.e., the source).  When the provider is the source, the service is said to be original.  Conversely, if the provider is some form of third party intermediary between user and source, the service is said to be syndicated.

External / Original:  “External services that are called directly by a user’s application.”

External / Syndicated:  “External services for which users call a third party provider or syndicator which would then call the original source on their behalf.”  Presumably in this type of structure, the syndicator would add some value for acting as intermediary.  For example, a syndicator could serve as a common front for many original service sources thereby presenting an additional interface abstraction and a common point of billing and support.

Internal / Original vs. Syndicated:  Based on the foregoing definitions, the notion of a syndicated internal service seems oxymoronic.  The taxonomic intent is to enable larger enterprises to make the distinction, for example, between point-to-point calling of a legacy API (i.e., original source) versus the use of an intermediate hub, messaging service, or some other abstraction layer (i.e., a form of syndication).

Classification:  Differentiation

This classification addresses the potential for multiple sources to provide functionally equivalent services and how the user perceives the relative value of those sources.  A service is referred to as a commodity if it is possible for multiple sources to provide functionally equivalent implementations of that service, whether or not multiple such sources actually exist.  In contrast, a service is referred to as branded if there can be only one source of that service.

External / Original / Commodity:  “Services provided by an original source that can also be offered by other sources.”  The functional equivalence of these services can enable a user to select a source based on non-functional factors such as price, performance, and reliability.  Examples might include data services such as weather or financial market data.  In this scenario, the commodity sourcing decision must be performed by the user.  Despite functional equivalence, each source may present differing interfaces to which the user must code.

External / Syndicated / Commodity:  “Services provided by a syndicator fronting for potentially multiple functionally equivalent sources.”  The key value of commodity syndication lies in the fact that functional equivalence does not imply interface equivalence.  For a given commodity service, a commodity syndicator has the opportunity to normalize interfaces across functionally equivalent sources, thus providing the user with a single stable interface per service.  This scenario would support the commodity sourcing decision being made either by the user or transparently by the syndicator.

External / Original / Branded:  “Services provided by an original source that can only be available from that source.”  The most common types of these services are APIs to specific applications or platforms.  For example, consider writing a mashup for your back office that uses the SalesForce API.  It cannot decide lightly to call a different CRM application since it is highly unlikely that its API will be functionally equivalent at the service level, not to mention the fact that your company’s data lives at SalesForce.

External / Syndicated / Branded:  “Services that can only be available from a single source, but are accessed through a syndicator.”  This class is included for taxonomic completeness although it is unclear what significant value the syndicator would provide in this case.  There may be some value in a single gateway to multiple branded services for billing, support, or auditing purposes, but this alone hardly seems compelling relative to the overhead.

Classification:  Session

This classification recognizes that certain logical operations may require multiple web service calls.  While this may seem like a technical distinction, its relevance to this taxonomy is in the context of commodity source selection.

… / Commodity / Stateless:  “Completely independent web service calls enabling commodity sourcing decisions on a per call basis if desired.”  This is the finest granularity of web service commoditization.  An example of this might be a request for a stock quote for a known ticker symbol.  A single call does the job and there is any number of functionally equivalent service sources for this information.

… / Commodity / Statefull:  “A logically related group of web service calls that all must be made to the same source, thus necessitating a single commodity sourcing decision for the group.”  An example might be obtaining a credit report on a company.  A first call requests a “list of similars” based on the company name.  The returned list includes a set of possible matches with additional data for disambiguation and source specific IDs.  After selecting the desired company from the list, the second call requests the actual report based on the ID.  The user may not care which source is used, but having made the sourcing decision for the first call, the rest of this conversation must return to the same source since it carries source specific information.

Summary

The last 5 years have seen the rapid proliferation of available web services and a growing appetite of Web 2.0+ developers anxious to consume them.  Thus far, the focus has been on what mashups and service oriented applications can do and how to achieve them functionally.  Going forward, we will see increased attention to qualities of service, stability, and source redundancy analogous to that of cloud computing.  Lack of maturity in these areas is among the factors holding back enterprises from full scale consumption of external web services in their business applications.  Concepts such as syndication and commoditization can play a key role in breaking through this barrier.