Hi Les, Thank you for considering making a contribution to the logback project. The modularization scheme for logback extensions you propose sounds quite reasonable. However, I should mention that logback is already split by logging event type (logback-access, logback-classic) with logback-core providing shared code, applying the core/classic/access separation to the modularization scheme for logback extensions, we could end up in 18 (=3x6) modules (core/access/classic x extensions/json/commmon/groovy/jackson/loggly/). If logback-classic is the only target for logback-extensions, this combinatorial problem obviously does not apply. To keep things simple, we could ignore logback-access and concentrate on extending only logback-classic. More importantly though, I personally cannot and do not wish to commit to the maintenance of logback-extensions. Thus, I would prefer to support logback-extensions as a separate project as far as the code is concerned. However, at the web-site level (http://logback.qos.ch), the two projects could be integrated by allowing you to manage on your own the branch under say http://logback.qos.ch/extensions/. Thoughts? -- Ceki http://twitter.com/#!/ceki On 08.03.2012 20:40, Les Hazlewood wrote:
Hi Ceki (et. al),
I'm trying to wrap my head around making it easy to add and support contributions/extensions to logback in a clean/modular way. For example, I'd like to see a JSON formatter and a Loggly appender added to Logback.
However, these additions probably don't make sense to be added to logback core/classic as they would bloat the library for those not using these features. As such, it makes sense (to me at least) to have a more modular source code organization where different features/extensions are represented as a dedicated Maven module. This way, people can easily (and deterministically) use a respective dependency depending on the feature they wish to enable. Clean and easy.
Now, with regards to a JSON formatter and a Loggly appender (which would likely use the JSON formatter), I'd envision something like this in the Logback source tree:
logback/ logback-access/ logback-classic/ logback-core/ ... logback-extensions/
Where 'logback-extensions' is a new Maven module. It would just be a wrapper module containing children. Below it, you might see the following:
logback-extensions/ json/ common/ groovy/ jackson/ loggly/ foo/ bar/ ...
In the above example, the logback-json module: 1) provides a 'common' sub module where JSON-specific needs are defined, and 2) has other sub-modules depending on _how_ you want JSON to be formatted.
You can depend on the logback-json-jackson dependency if you want to use Jackson, or you can depend on logback-json-groovy if you want to use the built-in JSON support in a Groovy 1.8+ environment. The 'loggly' extension could depend on logback-json-common.
The idea is that you can depend on a dependency that is copacetic with your intended runtime environment. I think this makes a lot of sense - we use it in Apache Shiro (http://svn.apache.org/repos/asf/shiro/trunk/support/) and it works very well for us.
Before I go off and create my own 'logback-extensions' project on GitHub, I'd rather contribute this back to Logback proper as a pull request if this is something you are willing to implement.
Thoughts?
Cheers,