Dynamic Coupling: Pot of Gold Under Semantic Rainbow

Copyright © 2014, Intellyx, LLC

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Dynamic Coupling

The Pot of Gold under the

Semantic Rainbow

Jason BloombergPresident

[email protected]

@theebizwizard

Copyright © 2014, Intellyx, LLC2

About Jason Bloomberg

• President of Intellyx, Global Advisory Firm focused on Digital Transformation through Architecting Agility– Formerly with ZapThink 2001 - 2013

• Contributor to Forbes– http://www.forbes.com/sites/jasonbloomberg

• Created the Licensed ZapThink Architect (LZA) SOA course & associated credential

• Run the Bloomberg Agile Architecture Certification Course around the world

• Buy my newest book, The Agile Architecture Revolution

• Include @theebizwizard in tweets


Human Interactions Always Have Context

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Every department, team, group, or interaction has its

own business context


Traditional Apps Have their Own Business Context


Don’t Shoehorn your Data

Shoehorning information into techie ideal of canonical data model woefully unrealistic


Why Semantic Interop has been Out of Reach

• Existing technology approaches have been too inflexible

• Require a more agile approach

• Not just about technology

We require Agile Architecture


What is Bloomberg Agile Architecture?

• Bloomberg Agile Architecture™ reinvents Enterprise Architecture (EA) to drive business agility across the organization

• New architecture paradigm• EA technique focused on

architecting agility


BAA Maturity Metamodel


Loose Coupling

• Abstract underlying code with contracted interface

• Separation of concerns between consumers & providers

• Can change underlying code without breaking interaction, as long as endpoints comply with contract

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Contracted Interfaces

• We must somehow contract interfaces in order to abstract the underlying functionality– Provides loose coupling– Some measure of flexibility

• Contracts (including REST’s uniform interface) are always a compromise – Interface itself now lacks

flexibility– IT becomes limiter of business

agility

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Pros & Cons of Loose Coupling

• Pros– Can make some changes

without breaking interaction– Increases flexibility of

distributed computing interactions

– Supports Service discoverability & late binding

• Cons– Inflexible interfaces limits

business agility– Challenges versioning

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The Importance of a Uniform Interface

• Web Services have custom operations– Unwanted tight coupling– Vendor incompatibilities

• REST has only HTTP verbs as operations (GET, POST, PUT, and DELETE)– HTTP verbs, URI structure,

and Internet Media Types fully define API

– Dramatic simplification of integration

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Deep Interoperability


Challenges of HATEOAS

• Central architectural constraint of REST• How to program client to obtain necessary

metadata via hyperlinks?• Hypermedia-based data

formats area of active research– Many immature options,

no clear best practice

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Hypermedia as the Engine of Application State


HATEOAS and Affordances

• Resolve URIs, process requests via a uniform interface

• Clients render representations that conform to standard Internet Media Types – Generalized affordances– Doesn’t matter what URI,

request, or representation as long as they conform to the constraints of the architecture P

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Does REST Provide Deep Interoperability?

• Deep Interoperability– Endpoints automatically negotiate

basis for integration– Transport & message protocols, API

contracts, data schemas• HATEOAS potentially allows for

deep interoperability– Difficult to program in practice– How to program software client to

know how to follow hyperlinks to obtain necessary metadata?

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Custom Media Types

• REST loose coupling depends upon Standard Internet Media Types (formerly called MIME types)

• Internet Media Types designed for display metadata– HTML, PDF, etc.

• REST’s answer for custom data formats are Custom Media Types

• Introduce tight coupling– How to communicate, maintain, & version them? P

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Automating HATEOAS

• Hypermedia affordances depend upon HATEOAS being handled manually

• A person changes the state of their application by clicking hyperlinks

• Code an arbitrary piece of software to serve as the RESTful client – May not have a user

interface– Knows how to follow

hyperlinks to gather all the metadata it needs to understand how to behave

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The Agility Platform

Your Application

Your Application

Application-Building

Tool

Your Application

Application-Building

Tool

Tool-Building Platform

Automated HATEOAS in Action


BAA Layers of Abstraction

META Dealing with Change (metaprocesses, metapolicies, etc. )

DYNAMICAbstract Models (dynamic schemas,

dynamic APIs, etc.)

ABSTRACTED (LOGICAL)

Abstracted Technology (schemas, software interfaces, etc.)

PHYSICALTechnology (software, middleware,

databases, etc.)


Working with Abstract Models

• Abstracts choice of schema

• Abstracts choice of API contract

• Abstracts semantic context

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Resolve to logical models at run time


Supporting Abstract Models in Software

• Tool-building platform (business agility platform)– All affordances, affords tool-

building capabilities• Application-building tool

– Affords application-building capabilities to non-developers

– Rich UI support– Non-imperative logic

• Event-driven, process-centric, and/or rules-based, for example

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Assembling the Pieces of Agile Architecture

• Architecting for change requires working at higher levels of abstraction

• Abstract models resolvable to capabilities at run time– Dynamic coupling– Dynamic schemas– Extreme late binding

Architect for Change

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Dynamic Coupling

• Tight coupling– Must code all nodes at

once• Loose coupling

– Interfaces abstract underlying code

• Dynamic coupling– Interfaces resolved at run

time

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Dynamic Schemas

• Rigid data schemas– Entity-Relational

Model, XML Schemas• Schemaless data

– Problem of implied schemas

• Dynamic schemas– Metadata modeled at

design time, resolved at run time

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Dynamic Schemas

• WSDL files, URIs, HTTP verbs, and Internet Media Types don’t contract message semantics

• Metadata describing such semantics scattered about– Reintroduces tight coupling &

inflexibility• Dynamic schemas abstract all

such semantic metadata in a consistent way

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How Late is your Binding?

• Early binding– Traditional integration

• Late binding– Web Service discovery– Content-based routing on

ESBs– DNS resolution for RESTful

endpoints• Extreme late binding

– Fully dynamic discovery– Resolve URIs & metadata

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Extreme Late Binding

• Metadata-driven, late-bound schemas

• Schemas (and all other metadata) bound in real time– Across the organization– Regardless of change

• Business entities maintain separate, dynamic business contexts


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Getting to Agile Architecture

Jason Bloomberg

President, Intellyx

[email protected]

@theebizwizard

Thank You!

Dynamic Coupling: Pot of Gold Under Semantic Rainbow

Technology

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