Thursday, October 6, 2011

Grails and Maven - blue grails

by Richard Vowles

One of the things that has kept me away from Grails for a long time - even after spending a couple of years knee-deep in it has been the extremely poor support for a clean build and release.

The combination of Gant scripts and source-code plugin dependencies, the use of Ivy as a dependency manager, endless outstanding bugs and a tendency to just not understand why this was so important (I'm sure everyone had their list) led me to abandon using Grails or pushing Grails in any real way in my work life while working at Sky Television (NZ). I still used it in a side project, but not in any anger and long since left the developers discussion list.

As I prepared to take on a new job doing Grails development again, going back from an environment that focused on neat, tidy granular artifacts that were tested and released, wired cleanly with Spring and assembled with clarity and speed was something I didn't want to loose. I learnt a lot from the two guys I worked with in terms of the use of Spring, Maven and API design. I only hoped that Grails would be able to live up to it now it had moved on.

On jumping back into Grails I saw that essentially little had changed (even if it was about to with 2.0 and binary plugins). Application design still seemed to encourage big single projects where all controllers, domain objects, services and so forth were all in the one project, making it harder and harder to test, longer and longer to build and deploy. Knowledge of Spring by users was limited, consequences of Hibernate ignored, discipline around tagging and releasing artifacts almost non-existent. EDIT: I mean this in the context of the Grails community as a whole:

  • Spring encourages the use of interfaces. Grails encourages you to inject the service's actual class by its name (e.g. userService for com.bob.UserService) but by using a def you can mock it. Its Groovy, but its nasty.
  • Grail's finders ignore the consequences of the SQL generates and most developers appear to not look at the SQL Hibernate generates. Hibernate does a bad job with anything thats not basic, and createCriteria is a demon. Whether this is better or worse than any other usage of it I'm not sure.
  • Grails doesn't come with a "release" script - crazy in my opinion. The concept of clean, build, tag, checkout from tag in a different place, build is critical to knowing you have a reproducible clean build. Not having it is crazy and is an artifact of people who don't use Maven, or one of the many who use Maven who don't use properly.

So for the past few months I have been working with the University of Auckland and TEIQ to build a set of best practices around modular Grails development, using Maven in the sanest way possible (and it is sane, and nice, and clean). Sorting out the way we deal with the inevitable buggy plugins (including the Grails Maven Plugin), building composites that bundle together packages of artifacts that relate, standardising web services structures and looking always for opportunities to make things better and cleaner, faster and clearer, better tested and more robust. Its a great opportunity and I thank TEIQ and particularly the University for giving me the chance to make a difference. And great people - did I mention great people?

As part of this work, we are taking some of what we have learnt and pushing it out into open source - or probably more open documentation. To make the best use of what we have done, we really need to have the Grails plugins that we use available as Maven artifacts - and I can't see the Grails guys happy about us doing that. I'm going to document it here on my blog - to make sure I do it (document it that is) - I'd recommend taking what I write if it works for your team and putting it in your Wiki and augmenting it over time.

The first thing I'm putting out there which may be of some worth to people who come to Grails and consider using Maven is my set of scripts I use. Its growing - but it provides me with a great set of shortcuts to the commands I regularly use. Enjoy :-)

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