Grails-Camel Plugin won't install or run

Question

Please note: Although this question involves a lib called Apache Camel I really think this is just a question about how modern Grails plugins work.

I am on Grails 2.4.2 here, and I am trying to use Apache Camel with Grails and found the Grails Routing plugin annd cannot even get it to install.

The directions say to install by issuing a grails install-plugin routing. When I do this I get:

grails install-plugin routing
Starting process on LT-IE-ZH/10.10.99.14
Loading Grails 2.4.2
|Configuring classpath
.
|Environment set to development
......Warning 
|
Since Grails 2.3, it is no longer possible to install plugins using the install-plugin command.
Plugins must be declared in the grails-app/conf/BuildConfig.groovy file.
Example:
grails.project.dependency.resolution = {
    ...
    plugins {
        compile ":routing:1.3.2"
    }
}

So I modify my BuildConfig.groovy like so:

plugins {
    // plugins for the build system only
    build ":tomcat:7.0.54"

    compile ":routing:1.3.2"

    ...lots of other stuff omitted for brevity

}

Then the plugin says to create routes, issue a grails create-route <RouteName>. So I do exactly that:

grails create-route OrderListener
Starting process on LT-IE-ZH/10.10.99.14
Loading Grails 2.4.2
|Configuring classpath
|Running pre-compiled script
|Script 'CreateRoute' not found, did you mean:
    1) CreateFilters
    2) CreatePom
    3) CreateApp_
    4) CreateController
    5) CreateHibernateCfgXml
Please make a selection or enter Q to quit: 

What is going on here?!? How do I install/use this plugin?!? Am I losing my mind, or does this plugin simply not work?

---

Update

I run grails clean-all, then grails refresh-dependencies then grails create-route OrderListener and I get:

Loading Grails 2.4.2
.
|Environment set to development
.....Error 
|
groovy.lang.MissingMethodException: No signature of method: CreateRoute.createArtifact() is applicable for argument types: () values: []
Error |
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
Error |
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
Error |
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
Error |
    at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
Error |

<huge stacktrace omitted>

Error |
    at org.codehaus.groovy.runtime.callsite.PogoMetaMethodSite$PogoCachedMethodSiteNoUnwrapNoCoerce.invoke(PogoMetaMethodSite.java:207)
Error |
    at org.codehaus.groovy.runtime.callsite.PogoMetaMethodSite.call(PogoMetaMethodSite.java:68)
Error |
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:112)
Error |
    at gant.Gant$_dispatch_closure5.doCall(Gant.groovy:381)
Error |
... 68 more

Answer 1

Whenever you make a change in BuildConfig.groovy be sure to run grails compile to trigger dependency resolution, which will download new and updated plugins and jars, and it will also compile your code which helps to ensure that things are minimally compatible at least.

But the core issue here is that the plugin's CreateRoute.groovy script is badly broken. It's missing an important include and doesn't come close to calling createArtifact correctly. As a workaround until the authors get this fixed, create a script in your app's scripts folder called CreateCamelRoute.groovy with this content:

includeTargets << grailsScript('_GrailsCreateArtifacts')

target(createCamelRoute: "Creates a new Camel Route.") {
    createArtifact(type: 'Route', path: 'grails-app/routes', name: argsMap.params?.get(0) ?: 'Example', suffix: 'Route')
}

setDefaultTarget(createCamelRoute)

It's intentionally named differently from the original because if Grails finds two with the same name it asks which one to use. This way you can just run

grails create-camel-route com.foo.bar.OrderListener

and it will work. Note that I changed the example a bit to include a package - always use packages :)