Maven, Hudson and Dynamic Clearcase Views

Question

This led on from the question about asking if Apache Maven and IBM Rational ClearCase integrated well. Thought I should write up what I found out - will require various edits, but I shall eventually get round to adding it all I hope.

Environment

ClearCase - Version 7.0.1.2 of ClearCase.

Maven - All of them, from the Maven website.

Hudson - Version 1.307 downloaded straight from the Hudson website

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Questions

• Does Maven run from a VOB?

I installed all the versions of Maven2 into a VOB 'stacked', i.e. I added Version 2.0 - labelled it, locked the label - then added 2.0.1 on top.

To prevent there being extraneous files, I used the -rnname flag in clearfsimport.

This way, I could simply use a label to specify the version of Maven I wanted access to in my configuration spec, but still keep the same path for the maven executable - /maven/bin/mvn.

Once all the versions were installed, I had no problem running Maven from there via a Dynamic View. Repositories are downloaded from an internal installation of Nexus to the users home directory as normal - and this saves any problems with checking in and out.

A benefit of keeping the tool in source control is that you can set company-wide settings (such as pointing to a internal repository) - then run that single instance of Maven from the VOB on any platform, which retains the settings you originally set!

In Maven projects, I only kept the src directory and the pom.xml in source control, as everything else can be auto-generated afterwards.

• Does Hudson work with ClearCase?

I had no problem setting up Hudson to run with ClearCase Dynamic Views. All it took was a symlink from the working directory for Hudson to the root of the view (in this case /view/xxx). The ClearCase plugin successfully ran ct lshistory to find if there had been any changes in the integration branch that developers merge into.

I did write a small script to set-up the initial environment for a job - just the config.xml and dynamic view symlink - so that the correct view was listed in the job and the initial settings were correct. Any enhancements by the users afterwards were then changes to the default template, rather than them setting it up themselves.

In the overall settings of Hudson, I used the $CLEARCASE_VIEW environment variable to set the path to the Maven executable. That way, the version of Maven depended on the version set in the configuration specification - rather than the one they selected within Hudson.

This saves extra administration on both the part of me (the admin) and my users.

• What Internal Repository Manager did you use?

I set up Sonatype Nexus to be the Internal Repository Manager - primarily because I read in the Sonatype blog that Hudson was going to get more integrated with Nexus, and we may as well be prepared for new enhancements in the future. I also believed, when I got it set up and tried it, that it was more prepared for a large commercial environment because you could tune the groups within the repository manager to be more flexible - useful for a great number of projects.

Answer 1

I am not using this SCM, but there is a Maven2 plugin called SCM that handles Clearcase.

Answer 2

I have some Maven repositories outside of ClearCase, for some third-parties libraries referential.

But I have never used Maven with ClearCase since they follow a different logic (Maven needs signed names for files, like myfile-1.2.jar, whereas ClearCase can store only myfile.jar, and record the fact it is version labeled 1.2)

That may have changed with the Maven2 ClearCase plugin reported by romaintaz, but there is still some bugs in this new product, as shown by this thread, when one runs it a second time without unco'ing the pom file. Maven is getting through the checkout fine but is not able to whatever the next step is.

INFO Checking out file: /opt/viewstore/common/maven/my_lf_ss/vobs/test_alm/LF_Build/pom.xml
INFO ERROR BUILD FAILURE
INFO INFO Unable to enable editing on the POM
Provider message:
The cleartool command failed.
Command output:
cleartool: Error: Element "/opt/viewstore/common/maven/my_lf_ss/vobs/test_alm/LF_Build/pom.xml" is already checked out to view "my_lf_ss".

Answer 3

I had a team building with Maven 2 and using Clearcase as the version control system. We used Archiva as the repository for built artifacts so the development team did not need to use the SCM plugin.

However, the continuous integration server was Continuum and that was relying on the SCM information in the POM. We had problems with the Clearcase SCM grabbing snapshot views using out branching strategy. One of my developers had to tweak the Clearcase SCM code to get it to work with our branches. We both moved on before we got round to contributing his fix.