I am an author, speaker, and loud-mouth on the design of enterprise software. I work for ThoughtWorks, a software delivery and consulting company. This site contains lots of my writing on software development, which primarily focuses on software design and agile methods. To find your way around this site, go to the intro guide.


News and Updates

My atom feed (RSS) announces any updates to this site, as well as various news about my activities and other things I think you may be interested in. I also make regular announcements via my twitter feed, which I copy to my facebook page.


Speaking at ThoughtWorks Rethink in Dallas

Mon 24 Nov 2014 10:58 EST

I’ll be speaking in Dallas on Saturday December 6th for a ThoughtWorks event We have also got Dave “Pragmatic” Thomas in, to talk about the death of agile. I’ll be speaking with my colleague, Molly Bartlett Dishman, about how architecture works in an agile environment.


photostream 78

Sun 23 Nov 2014 17:06 EST

Arnold Arboretum, Boston, MA


Integration and Component tests for Microservices

Thu 20 Nov 2014 10:48 EST

Toby Clemson continues his discussion of techniques for testing microservices, with two more styles of testing. Integration tests probe the interaction a service has with its data stores and external components. Component tests provide a coarse-grained test of the entire service, which can be usefully performed both in-process and out-of-process.


Retreaded: TechnicalDebtQuadrant

Wed 19 Nov 2014 09:29 EST

Retread of post orginally made on 14 Oct 2009

There's been a few posts over the last couple of months about TechnicalDebt that's raised the question of what kinds of design flaws should or shouldn't be classified as Technical Debt.

more ...


Testing Strategies in a Microservice Architecture

Tue 18 Nov 2014 09:25 EST

Microservices has been quite the topic of conversation this year, with a rapid rise of interest. But although this architectural style is often a useful one it has its challenges, which can easily lead a less experienced team into trouble. Testing is a central part of this challenge, which is particularly relevant for those of us that consider testing to be a central part of effective software development.

My colleague Toby Clemson has responded to this question by distilling his experiences into an infodeck that explains the various testing techniques to use with microservices and when to use them. The first installment outlines the anatomy of a microservice architecture and explains the role of the first testing technique: unit testing.

read the deck…


photostream 77

Sun 16 Nov 2014 09:50 EST

Great Wall, China


Updates to Collection Pipelines

Tue 04 Nov 2014 08:49 EST

Over the last few weeks I’ve been quietly making a bunch of small updates to my article on collection pipelines. To the main text I’ve added a subsection contrasting them with Nested Operator Expressions. I’ve also added several operators to the operation catalog, including slice and various set operations.


Architecture of Morrisons OrderPad

Tue 28 Oct 2014 09:40 EDT

Morrisons OrderPad is a tablet web-application that helps staff in supermarkets place orders for new stock as they walk around the store. My colleague Rob Miles and I felt that the resulting application makes a good expositional architecture for a tablet web application backed by a lightweight java server. We highlight the separation of application control and DOM interaction on the client, using small, focused frameworks on the server, the broad-stack testing environment, and the use of a pilot project to understand what features were needed.



Continuous Integration and Delivery

For a long time I’ve been a champion of Continuous Integration which reduces integration risk by integrating early and often, an application of the principle of Frequency Reduces Difficulty. We’ve found CI to be a core technique at ThoughtWorks and use it almost all the time. At the heart of this is a style of development that minimizes long feature branches with techniques like Branch By Abstraction and Feature Toggles.

While this is useful, there was still risk present from software that works in the development environment to getting it to work in production. As a result we developed Deployment Pipelines to reduce this risk, moving closer to our aim of Continuous Delivery: building software in such a way that we confidently deploy the latest builds into production whenever there is a business need. We find this improves feedback, reduces risk, and increases the visibility of project progress.

For more information: take a look at my guide page on Continuous Delivery.


NoSQL Databases

I’ve been involved in enterprise software for two decades and while we’ve seen huge technological change during that time, the relational database has been a constant figure. Previous attempts to dethrone relational databases have failed, but some people think the new rise of NoSQL databases will finally consign relational databases to history. While I think relational databases are going to an important part of the landscape for a long time, I do think that there is a big change coming in the database field.

I’ve been collaborating with my colleague Pramod Sadalage, on exploring and explaining this shift. For more information take a look at the nosql guide.


TW logo

I discovered ThoughtWorks in 2000: then a small American company whose philosphy of software development was remarkably similar to my own. Now we’ve grown to around 2500 people world-wide, but kept the values that make us special. My colleagues have built critical systems for many clients in that time, and I’ve learned many lessons from them. While doing this, we found we often didn’t have the tools we needed, so we started to build them. This led to open-source tools such as CruiseControl, Selenium, Frank, and Moco as well as commercial products.

I have many opportunities, but I’ve stayed at ThoughtWorks because of the quality of my colleagues, who include both well-known speakers and those who may not be famous names but do an excellent job of software delivery (and feed me the information to write about). We are inspired by working with each other and our unusual three-pillar philosophy that raises professional excellence and social justice to the same level as financial performance.

And we are always looking for more great people to join our curious company. Maybe I’ll see you in one of our offices some day.


An Appropriate Use of Metrics

As with any style of process, agile software development has bred lots of interest in metrics. The thinking goes something like this, “We need a number to measure how we’re doing. Numbers focus people and help us measure success.” Whilst well intentioned, management by numbers unintuitively leads to problematic behavior and ultimately detracts from broader project and organizational goals. Metrics inherently aren’t a bad thing; just often, inappropriately used. Pat Kua, author of The Retrospective Handbook, demonstrates these issues and offers an alternative approach that uses metrics well.



Upcoming Talks
Dec
6ThoughtWorks Rethink: Dallas


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