When using clojure & lein for larger systems composed of many modules, you may know the multibuild problem - it's ugly and boring to release / test / ancient all your modules one after another manually! And it has to be done ordered by dependency!

On the other hand, you may insist on having multiple modules, because it's handy to have independent release cycles or different access policies.

Thats exactly our situation at dda-pallet (a clojure dev-ops-system we maintain).

Fortunately, there are some ways to solve this situation in lein:

• sub: Can be used, if the directory location of modules is defined. See more at: https://github.com/kumarshantanu/lein-sub
• modules: Indicated if git submudules are in use. See more at https://github.com/jcrossley3/lein-modules

We have a controlled development environment (our ide ist set up by dda-pallet - all repos are cloned to a well defined place) so we decided to give sub a try. Our git repository layout on disk looks like this:

• ~/code/pallet/
  • dda-backup-crate/
  • dda-basic-crate/
  • ...
  • dda-pallet/
  • dda-pallet-masterbuild/

The masterbuilds project.clj now looks like:

(defproject org.domaindrivenarchitecture/dda-pallet-masterbuild "0.1.0-SNAPSHOT"
  ...
  :sub ["../dda-pallet"
        ...
        "../dda-backup-crate"]
  :plugins [[lein-sub "0.3.0"]]
  ...

_{^{Details at: https://github.com/DomainDrivenArchitecture/dda-pallet-masterbuild/blob/master/project.clj}}

And the dependent project looks like:

(defproject org.domaindrivenarchitecture/dda-pallet "0.1.0-SNAPSHOT"
  ...
  :profiles {:dev
             {:plugins
              [[lein-sub "0.3.0"]]}
            }}
  ...

_{^{Details at: https://github.com/DomainDrivenArchitecture/dda-pallet/blob/master/project.clj}}

Now we can do things like

lein sub ancient upgrade :interactive :allow-all

this will result in testing all projects for ancient dependencies ...

That's quite cool ... isn't it?