Book Review: "Instant Flask Web Development" by Ron DuPlain

"Instant Flask Web Development" by Ron DuPlain (Packt Publishing http://www.packtpub.com/flask-web-development/book) is intended to be an introduction to Flask, a lightweight web application framework written in Python and based on the Werkzeug WSGI toolkit and Jinja2 template engine.

The book takes a tutorial style approach, building up an example appointment-management web application using Flask and introducing various features of the framework on the way. As the example application becomes more complicated, additional Python packages are covered which are not part of the Flask framework (for example SQLAlchemy for managing interactions with a database backend, and WTForm for handling form generation and validation) along with various Flask extensions that can be used for more complicated tasks (for example managing user logins and sessions). The final section of the book gives an overview of how to deploy the application in a production environment, using gunicorn (a Python WSGI server) and nginx.

Given its length (just short of 70 pages) the book is quite ambitious in the amount of ground that it attempts to cover, and it's quite impressive how much the author has managed to pack in whilst maintaining a light touch with the material. So while inevitably there is a limit to the level of detail that can be fitted in, there are some excellent and concise overviews of many of the topics that could act as excellent starting points for more experienced developers (for me the section on SQLAlchemy is a particular highlight). Overall the pacing of the book is also quite sprightly and conveys a sense of how quickly and easily Flask could be used to build a web application from scratch.

The flipside of the book's brevity is that it cannot possibly contain everything that a developer needs to know (although this is mitigated to some extent by extensive references to online documentation and resources). In this regard it is really more a showcase for Flask, and is best viewed as a good starting point for someone wishing to quickly get up to speed with the framework's potential. I'd also question how suitable this is for newcomers to either Python, or to web programming in general - I felt that some of the concepts and example code (for example the sudden appearance of a feature implemented using Ajax) might be a bit of a stretch for a novice. Also there are some occasional frustrating glitches in the text and example code which meant it took a bit of additional reading and debugging in places to get the example application working in practice.

In summary then: I'd recommend this book as a good starting point for developers who already have some familiarity with web application development, and who are interested in a quick introduction to the key components of Flask and how they're used - with the caveat that you will most likely have to refer to other resources to get the most out of it.

Disclosure: a free e-copy of this book was received from the publisher for review purposes; this review has also been submitted to Amazon. The opinions expressed here are entirely my own.

Software Carpentry Bootcamp Manchester

I've spent the last two days as a helper at a Software Carpentry Bootcamp held at the University of Manchester, and it's been really interesting and fun. Software Carpentry is a volunteer organisation and runs the bootcamps with the aim of helping postgraduate students and scientists become more productive by teaching them basic computing skills like program design, version control, testing, and task automation. Many of the materials are freely available online via the bootcamp's Github page: along with transcipts of some of the tutorials there are some excellent supporting materials including hints and tips on common Bash and editor commands (there's even more on the main Software Carpentry website).

The bootcamp format consisted of short tutorials alternating with hands-on practical exercises, and as a helper the main task was to support the instructors by offering assistance to participants if they found themselves stuck for some reason in the exercises. I'll admit I felt some trepidation beforehand about being a helper, as being put on the spot to debug something is very different to doing it from the relaxed privacy of my desk. However it turned out to be a both very enjoyable and very educational experience; even though I consider myself to be quiet a proficient and experienced shell and Python programmer, I learned some new things from helping the participants both with understanding some of the concepts and with getting their examples to work.

There were certainly lots of fresh insights and I learned some new things from the taught sessions too, including:

• Bash/shell scripting: using $(...) instead of "backtick" notation to execute a command or pipeline within a shell script;
• Version control: learning that Bitbucket now offers free private repositories (and a reminder that git push doesn't automatically push tags to the origin, for that you also need to explicitly use git push --tags);
• Python: a reminder that slice notation [i:j] is inclusive of the first index i but exclusive of the second index j, and independently that string methods often don't play well with Unicode;
• Testing: a reminder that writing and running tests doesn't have to impose a big overhead - good test functions can be implemented just with assert statements, and by observing a simple naming convention (i.e. put tests in a test_<module>.py file, and name test functions test_<name>), Python nose can run them automatically without any additional infrastructure.
• Make: good to finally have an introduction to the basic mechanics of Makefiles (including targets, dependencies, automatic variables, wildcards and macros), after all these years!

As a helper I really enjoyed the bootcamp, and from the very positive comments made by the participants both during and at the end it sounded like everyone got something valuable from the two days - largely due to the efforts of instructors Mike Jackson, David Jones and Aleksandra Pawlik, who worked extremely hard to deliver excellent tutorials and thoroughly deserved the applause they received at the end. (Kudos should also go to Casey Bergman and Carole Goble for acting as local organisers and bringing the bootcamp to the university in the first place.) Ultimately the workshop isn't about turning researchers into software engineers but rather getting them started with practices and tools that will support their research efforts, in the same way that good laboratory practices support experimental research. (This isn't an abstract issue, there can be very real consequences as demonstrated by cases of Geoffrey Chang, McKitrick and Michaels, and the Ariane 5 rocket failure - the latter resulting in a very real "crash".)

If any of this sounds interesting to you then the Software Carpentry bootcamp calendar shows future events planned in both Europe and the US, so it's worth a look to see if there's one coming up near your location. Otherwise you could consider hosting or running your own bootcamp. Either way I'd very much recommend taking part to any researchers who want to make a positive impact on their work with software.