Bootstrap, LESS and Maven plugin - maven

Question

I'm looking for some information on how to get LESS compiling Bootstrap using the Maven plugin. I need to compile bootstrap with my less because I use bootstrap less in my files. Right now I have the maven plugin compiling less files into css, but it breaks when I try to get it to compile bootstrap less. I think this might be a version issue, but just want to know if anyone's been able to figure this out or has a better approach.
pom.xml
<plugin>
<groupId>org.lesscss</groupId>
<artifactId>lesscss-maven-plugin</artifactId>
<version>1.3.3</version>
<configuration>
<sourceDirectory>${project.basedir}/src/main/webapp/less</sourceDirectory>
<outputDirectory>${project.build.directory}/${project.build.finalName}/css</outputDirectory>
<compress>true</compress>
<includes>
<include>bootstrap/bootstrap.less</include>
<include>test.less</include>
</includes>
<force>true</force>
</configuration>
<executions>
<execution>
<goals>
<goal>compile</goal>
</goals>
</execution>
</executions>
</plugin>
I running the above in a run configuration that calls "clean lesscss:compile"
error
Failed to execute goal org.codehaus.mojo:lesscss-maven-plugin:1.0-beta-3:compile (default-cli) on project FastTest: Error while compiling LESS source: bootstrap\alerts.less: Syntax Error on line 57: [object Object] (compile.js#1) -> [Help 1]
I'm not sure why it's going after the first item in the list for bootstrap so I renamed bootstrap.less to see if it ran and this is what I got:
Failed to execute goal org.codehaus.mojo:lesscss-maven-plugin:1.0-beta-3:compile (default-cli) on project FastTest: Error while compiling LESS source: bootstrap\abootstrap.less: Syntax Error on line 686: [object Object] (compile.js#1) -> [Help 1]

Answer 1

You are not compiling your code with correct plugin.
You are defining:
<groupId>org.lesscss</groupId>
<artifactId>lesscss-maven-plugin</artifactId>
<version>1.3.3</version>
But from output it is obvious that a different plugin was triggered:
org.codehaus.mojo:lesscss-maven-plugin:1.0-beta-3

Answer 2

Seems a newer version of less is required for the maven plugin since bootstrap uses features that require less version 1.4.0

Answer 3

Your plugin-version issue notwithstanding, you can override the compiler being used by the Maven Plugin...
Download the latest lesscss JS file from lesscss.org, and put it in your project's scripts/js folder, then add a lessJs node into your plugin's configuration:
<configuration>
<lessJs>${project.basedir}/.../less.?.?.?.min.js</lessJs>
...
</configuration>
Now the plugin will use the JS file to compile, instead of it's own built-in, often outdated compiler.
I think the latest JS release is now 1.6.3.
Hope this helps!
Tze

Answer 4

If you are using the newest version of Bootstrap you will need Less 1.6.x to compile the Less files.
See http://blog.getbootstrap.com/2014/01/30/bootstrap-3-1-0-released/ that writes:
We've switched from Recess to grunt-contrib-less for our compiler, giving us access to Less 1.6.x (as opposed to 1.3.x with Recess).
The official Less Maven Plugin org.lesscss:lesscss-maven-plugin that you use does currently only support Less 1.3 and is not actively maintained at the moment. But I released a fork of it to Maven Central yesterday that supports Less 1.6.1 and contains other open pull requests from the plugin.
It is de.sandroboehme.lesscss:lesscss-maven-plugin:1.6.1.1.0 from https://github.com/sandroboehme/lesscss-java. Using it could solve your problem.
BTW: If somebody happens to be interested, contributers are wanted for the official Maven plugin. See https://github.com/marceloverdijk/lesscss-maven-plugin/issues/39

Answer 5

In the mean time I would use the Frontend Maven Plugin. See
https://github.com/eirslett/frontend-maven-plugin