How to get Maven project version to the bash comma

Question

Previous I issued a question on how to change Maven project vesion from command line which lead me to a new issue.

Previously I was able to get the version number since the version was stored as a property that was easy to grep and parse from the command line (bash). Now that the pom.xml element is used for this, it no longer is unique since all the dependencies and maybe some others too use this. I think there is no way to get the current version number with a bash script without external tools for parsing xml or some very context-aware sed command.

The most clean solution in my opinnion would be for Maven to hand out this version information. I was thinking of writing a custom maven plugin for retrieving different properties but I thought I'd ask here first.

So, is there any easy way to get the value of ${project.version} to the command line? Thanks in advance.

Solution

Thank you for the help. I had to cd to the directory manually but that can be done easily. In my bash script I have

version=`cd $project_loc && mvn org.apache.maven.plugins:maven-help-plugin:2.1.1:evaluate -Dexpression=project.version | sed -n -e '/^\[.*\]/ !{ /^[0-9]/ { p; q } }'`

Which gives me the current version that I can then advance. Grepping might be simplier but I thought I'd like as robust as possible, so I'm satisfied with the first line that starts with a number and try to handle this as a version number.

# Advances the last number of the given version string by one.
function advance_version () {
    local v=$1
    # Get the last number. First remove any suffixes (such as '-SNAPSHOT').
    local cleaned=`echo $v | sed -e 's/[^0-9][^0-9]*$//'`
    local last_num=`echo $cleaned | sed -e 's/[0-9]*\.//g'`
    local next_num=$(($last_num+1))
    # Finally replace the last number in version string with the new one.
    echo $v | sed -e "s/[0-9][0-9]*\([^0-9]*\)$/$next_num/"
}

And I use this by simply calling

new_version=$(advance_version $version)

Hope this helps someone.

Answer 1

I kept running into side cases when using some of the other answers here, so here's yet another alternative.

version=$(printf 'VER\t${project.version}' | mvn help:evaluate | grep '^VER' | cut -f2)

Answer 2

Tom's solution with the Exec Maven Plugin is much better, but still more complicated than it needs to be. For me it's as simple as:

MVN_VERSION=$(mvn -q \
    -Dexec.executable=echo \
    -Dexec.args='${project.version}' \
    --non-recursive \
    exec:exec)

Answer 3

I noticed some spurious Downloaded: lines coming in the output that were breaking my original assignment. Here's the filter I've settled on; hope it helps!

version=$(mvn org.apache.maven.plugins:maven-help-plugin:2.1.1:evaluate -Dexpression=project.version | egrep -v '^\[|Downloading:' | tr -d ' \n')

EDIT

Not 100% sure why, but when running this through a post-build script in Jenkins, the output was coming out as [INFO]version, e.g. [INFO]0.3.2.

I dumped the output to a file and ran it through my first filter directly from BASH, it works fine.., so again, unsure what's going on in Jenkins land.

To get it 100% in Jenkins, I've added a follow-up sed filter; here's my latest

version=$(mvn org.apache.maven.plugins:maven-help-plugin:2.1.1:evaluate -Dexpression=project.version | egrep -v '^\[|Downloading:' | tr -d ' \n' | sed -E 's/\[.*\]//g')

EDIT

One last note here.. I found out tr was still resulting in things like /r/n0.3.2 (again only when running via Jenkins). Switched to awk and the problem has gone away! My final working result

mvn org.apache.maven.plugins:maven-help-plugin:2.1.1:evaluate -Dexpression=project.version \
| egrep -v '^\[|Downloading:' | sed 's/[^0-9\.]//g' | awk 1 ORS=''

Answer 4

mvn help:evaluate -Dexpression=project.version | sed -e 1h -e '2,3{H;g}' -e '/\[INFO\] BUILD SUCCESS/ q' -e '1,2d' -e '{N;D}' | sed -e '1q'

I'm just adding small sed filter improvement I have recently implemented to extract project.version from maven output.