Category Archives: Reviews

This is a very useful introduction to key cloud concepts and how common challenges can be met. It’s also a good overview of how Microsoft technologies may fit into these solutions, but avoids becoming so Microsoft-centric that it becomes useless in other contexts. Unfortunately, however, the overall structure means that this is not a book designed for easy end to end reading. It may work better as a reference work, but that reduces what should have been its primary value.

The book starts with a good introduction and list of the patterns and supporting "guidance" sections, and is then followed first by the patterns, and then the guidance sections (useful technology primers). This is where things break down a bit, as the patterns are presented in alphabetical order, which means a somewhat random mix of topics, followed by the same again for the guidance sections. I attempted to read the book cover to cover over about a week and I found the constant jumping about between topics extremely confusing, and the constant repetition of common content very wearing. In addition by presenting the guidance material at the end it is arguably of less value as most of the concepts have already been covered in related patterns. Ultimately the differentiation between the two is very arbitrary and not helpful. For example is "throttling" really a pattern or a core concept? If "throttling" is a pattern why is "autoscaling" not described as a pattern?

The book would be about 10 times better if it were re-organised into half a dozen "topics" (for example data management, compute resource management, integration, security…), with the relevant guidance and overviews first in each topic, followed by the related patterns which could then be stripped of a lot of repetitive content, and topped off with common cross-reference and further reading material.

This is not just a book about cloud specifics. A lot of the material reflects general good practice building and integrating large systems, even for on-premise deployment, and reinforces my view that "Cloud" is just a special case of this established body of practice. As a result there’s quite a lot of overlap with older pattern books especially Enterprise Integration Patterns, which is also directly referenced. The surprisingly substantial content related to message-based integration, confirms my view that this is still the best model for loosely coupled extended portfolios, but I would have appreciated more on the overlap with service technologies.

The overlap with other standard pattern books might have been managed just by referencing them, but this would play against Microsoft’s objective of making this material readily available to all readers at low cost.

The book is spectacularly good value for money, especially as you can download it free from Microsoft if you are prepared to do a bit of juggling with document formats. That it forms part of a series also available under similar options is even better. This perpetuates Microsoft’s tradition of providing cheap, high-quality guidance to developers and sits in sharp contrast with the high costs of comparable works from not only independent publishers (which may be understandable) but other technology vendors.

The book does assume some familiarity with Windows Server concepts, for example worker roles vs machine or application instances, and doesn’t always explain these terms. A glossary or an clear reference to a suitable external source would have been useful.

At a practical level I’m pleased to see that the Kindle version works well, with internal links hyperlinked and clear diagrams, plus access to each pattern directly from the menu in the Android Kindle app. Offset against this are a few cases of poor proofreading related to problems with document format conversions, in particular with characters like apostrophes turned into garbage character strings.

Overall I found this a useful book, and I’m sure it will become a valuable reference work, but I just wish the authors and editors had paid more attention to the high-level structure for those trying to read it like a traditional book.

One of the most influential architecture books of the early 00s was Enterprise Integration Patterns by Gregor Hohpe and Bobby Woolf. That book not only provided far and away the best set of patterns and supporting explanations for designers of message-based integration, but it also introduced the concept of a visual pattern language allowing an architecture (or other patterns) to be described as assemblies of existing patterns. While this concept had been in existence for some time, I’m not aware of any other patterns book which realises it so well or consistently. The EIP book became very much my Bible for integration design, but technology has moved on an service-based integration is now the dominant paradigm, and in need of a similar reference work.

The Service Design Patterns is in the same series as the EIP book (and the closely related Patterns of Enterprise Application Architecture), and overtly takes the earlier books as a baseline to build an additional set of patterns more directly related to Service-oriented integration. Where the earlier books’ content is relevant, it is just referred to. This helps to build a strong library of patterns, but also actively reinforces the important message that designers of newer integration architectures will do well to heed the lessons of previous generations.

The pattern structure is very similar to the one used in the EIP book, which is helpful. The "Headline" context description is occasionally a bit cryptic, but is usually followed by a very comprehensive section which describes the problem in sufficient detail, with an explanation of why and when alternative approaches may or may not work, and the role of other patterns in the solution. The text can be a little repetitive, especially as the authors try to deliver the specifics of each pattern explicitly for each of three key web service styles, but it’s well written and easily readable.

This is not a very graphical book. Each pattern usually has one or two explanatory diagrams, but they vary in style and usefulness. I was rather sad that the book didn’t try to extend the original EIP concept and try to show the more complex patterns as assemblies of icons representing the simpler ones. I think there may be value in exploring this in later work.

One complaint is the difficulty of navigating within the Kindle edition, or in future using it as a reference work. Internal references to patterns are identified by their page number in the physical book, which is of precisely zero use in the Kindle context. In addition the contents structure which is directly accessible via the Kindle menu only goes to chapter level, not to individual patterns. If you can remember which chapter a pattern is in you can get there via the contents section of index, but this is much more difficult than it should be. In other pattern books any internal references in the Kindle edition are hyperlinked, and I don’t understand why this has not been done here.

To add a further annoyance, the only summary listings of the patterns are presented as multiple small bitmapped graphics, so not easily searchable or extractable for external reference. An early hyperlinked text listing with a summary would be much more useful. Please could the publishers have a look at the Kindle versions of recent pattern books from Microsoft Press to see how this should be done?

A final moan is that the book is quite expensive! I want to get all three books in the series in Kindle format (as well as having the hardcover versions of the two earlier books, purchased before ebooks were a practical reality), and it will cost over £70. This may put less pecunious readers off, especially as there’s so much front matter that the Kindle sample ends before you get to the first real pattern. That would be a  shame, as the industry needs less experienced designers to read and absorb these messages.

These practical niggles aside, this is a very good book, and I can recommend it.

This book sets out to provide a concise overview of the current state of, and best practices for, Service Oriented Architecture. While it may achieve that for some managerial readers, it is simultaneously too general for those with more background, and may be too terse for those with less technical understanding.

The authors and editors have clearly set themselves the admirable aim of producing a short and concise overview of the field. Unfortunately in the quest for brevity they have ended up with a terse, dry and dense writing style which is very difficult to read. At times it feels almost like a game of "buzzword bingo". I frequently had to re-read sentences several times to understand the authors’ intended relationships between the elements, and I’m a very experienced integration architect.

At the same time, for a book on architecture there are very few explanatory diagrams, wordy descriptions being used instead. To add insult to injury a few low-value diagrams such as one depicting the cycle of interaction between business and IT change drivers are used repeatedly, when once would be enough.

The first chapter provide a overview of service orientation and its key principles, characteristics, goals and organisational implications.  This is followed by a chapter on service definition and composition. Ironically this part of the book is is quite repetitive, but manages to omit some key concepts. There’s no real concrete explanation of what a service is or does – maybe that’s taken as read, but a formal definition and some examples would go a long way. Likewise there’s nothing at this point on basic concepts such as service contracts and self-description, synchronous vs asynchronous operation or security. The second chapter goes into some detail on the idea of service composition but only really deals with the ideal green-field case where functionality can be developed new aligned exactly to business functions.

The following chapter on the SOA manifesto is better, but again doesn’t recognise the realities of real enterprise portfolios, with legacy systems, package solutions and external elements which must be maintained and exploited, and non-functional priorities which must be met.

Chapter 5 deals with service-related technologies and their potential interactions. This is good, and for me represented the core value of the book, but is crying out for some diagrams to supplement the lengthy text. There are good notes on service definition under Model Driven Service Design, but this key topic should really have been a major section in Chapter 3 in its own right. The statements about technical architecture are rather simplistic, with an overall position of "this is expensive and difficult, or just use the cloud" which is not necessarily right for all organisations.

The next chapter, on business models, is very prescriptive. It is also slightly misleading in some places about the role of IT in transactional services – such services are delivered by a business unit, possibly but not necessarily enabled by and carried through an IT service. It would be perfectly viable in some cases for specific services to have a manual implementation. This is well explained in the case study, but not here or in the Business Process Management section of the previous chapter.

The final chapter of the main text is a "case study" describing the wholesale transformation of a car rental company through adoption of service, agile and cloud approaches. It feels slightly contrived, especially in terms of its timeline, the preponderance of successes, and the surprising lack of resistance to CIO-led business change. However it fills a useful gap by explaining much better than the technologies chapter how the different technologies and approaches fit together and build on one another.

Appendix A is a taster for the other books in the series. Unfortunately the content is presented as small images which cannot be resized and are almost unreadable in the Kindle version. It has also been "summarized", with the result that it appears to add very little meaningful detail to what has already been said.

Appendix B is a useful expansion of the main text regarding organisational preparation, maturity levels and governance for SOA. I would personally have been tempted to merge the first two parts to the main text rather than positioning them as an appendix, where they are necessarily repetitive of some material which has already been read.

Appendix C is another taster for one of the other books in the series, this time with an overview of cloud computing. While this is at a fairly high level, it’s a useful and well-written overview for those unfamiliar with the concepts.

Overall this is a frustrating book. There is some good material, but missing key "reality checks" and presented in a terse, text-heavy style which makes it harder to read than it should be.