Specify artifact version outside of pom - maven-2

Is there a way to specify the artifact version outside of the POM file?
I have 2 CI projects that build an artifact. One builds a "stable" development version from a 'develop' branch and the other builds an unstable version which is the result of merging all active feature branches into the develop branch. I want the stable version to build as xyz-1.0.jar and the integration build to go in as xyz-1.0-SNAPSHOT.jar. Is there a way for the CI job to run a maven task or specify via the command line if a release or snapshot jar should be built without manually modifying the POM? Currently I have the version specified as 1.0 in the pom. I considered using the release plugin but I don't want the automatic version number increase and tagging that it does.

Short answer: no. And here are some additional remarks:
It doesn't make much sense to use a "released" version (i.e. non SNAPSHOT) for a branch under CI since released versions are not downloaded again even if a newer version is available.
Released versions should be tagged (e.g. 1.0), maintenance is done is in a branch derived from the tag (e.g. 1.0.1-SNAPSHOT).
If you want to distinguish versions built from different branches, use different versions in the POMs.

I was able to accomplish this by using a property in my POM and then overriding it via the command line.
pom.xml:
...
<version>${artifactVersion}</version>
<properties>
<artifactVersion>1.0</artifactVersion> <!-- default version -->
</properties>
...
Then overriding with mvn -DartifactVersion=1.0-SNAPSHOT package
But Pascal's answer above is more in line with what I was really asking. My solution is more of a workaround I feel.

You should be able to achieve this using maven profiles

Related

Publishing POMs via Maven and inserting build version info

I'm building Maven projects via TeamCity/Git and trying to insert the TeamCity build numbers in the pom.xml that gets published to my repository upon a successful build. Unfortunately I can't determine how to publish a pom.xml with the substitutions inserted.
My pom.xml contains info like:
<version>${build.number}</version>
where build.number is provided by TeamCity. That all builds ok, and if (say) build.number = 0.1, then the deployment is a pom.xml to a directory with 0.1. All well and good.
However, the pom.xml that is deployed is the pom.xml without the substitutions made. i.e. Maven is running with a pom.xml with appropriate substitutions, but deploys the initial version and so I get
<version>${build.number}</version>
in the final pom.xml. How can I get the build version number in the pom.xml ?
I wouldn't use this approach because it makes building a project checked out from the SCM not possible without providing the build.number property. I don't think that this is a good thing. Maybe I'm missing something though.
Actually, I don't get what you are trying to achieve exactly (why don't you write the build number in the manifest for example). But, according to the Maven Features on the Teamcity website:
By default, it also keeps TeamCity build number in sync with the Maven version number (...).
Couldn't that be helpful? There is another thread about this here.
Try to use generateReleasePoms property of maven-realease-plugin, maybe that helps a little.

maven snapshot repositories

My project depends on a 3rd party library that only has snapshots in its maven repository (no releases, which seems strange, but that's how it is). Every time I do a full build (and clean my local .m2 repository) maven will obviously go and grab the latest build.
My repository proxies the one with the snapshots in it, is there anyway to tell my repository to stop pulling new versions and basically just keep the current version? I really don't want to be pulling a new build every night.
The only thought I had is to manually label the current versions, but there quite a few dependencies and they are all dependent on the SNAPSHOT versions. Is there an easier way to do this?
thanks,
Jeff
Take a look at this blog entry from sonatype: Best Practices for 3rd Party Snapshot Dependencies
I usually install the file to my proxy or local repo as a certain version, and then refer to that version. Then you don't risk the snapshot disappearing out from under you.
Do you run the build with the -U ( -update-snapshots ) option ? If so, try without.
Else, if there is only this dependency on the repository, you could just disable this repository, and Maven will keep using the last version it finds on the local repository.
Did you try to specify the <updatePolicy> with the never strategy in the <snapshots> element of your <pluginRepository>? See Plugin Repositories and Repositories.
Use the --no-snapshot-updates option to suppress SNAPSHOT updates.
e.g.
$ mvn --no-snapshot-updates compile

Integrating Maven & Non-maven projects

I'm currently working on two projects simultaneously:
My main project (built with maven)
A spike of an open source project, which my main project depends on (not build with maven)
How do I set up maven to use the OSS project as a dependency with the least amount of friction, given that I'm often developing the two in tandem?
I can think of several solutions:
Mavenize the existing OSS project. This is of course the "ideal" option but often not feasible (even if you introduce the new build system in parallel of the existing one). The project has likely an existing project structure that differs from Maven's standard layout. Changing the existing layout and build script may not be desired by developers, adapting a Maven build to use a non standard layout can be painful. In both case, you're screwed.
Wrap the existing Ant build with Maven. This can be nice if you want to include the build of the OSS project in the lifecycle of your project and have both of them built in one step. You can check this answer on SO for details on how to do this.
Use Apache Ivy or Maven Ant Task in the existing build to produce and install a Maven artifact in your local repository. Use this artifact as a regular dependency in your Maven project (except that you'll have to declare its transitive dependencies manually). This is maybe the quicker and less intrusive approach if building both project separately is not a problem.
It looks like you choose option 3. I think it's a good choice for a quick win.
The solution I've used is the maven-ant tasks (http://maven.apache.org/ant-tasks/).
I added an install task onto the build.xml file, which installs the compiled .jar into the local repo.
While adding a full-fledged pom to the project would defintely be the best approach, this is a major chunk of work, and inflicts maven on the project (where the other users would prefer not to use it).
I think you probably need to bite the bullet and set up a POM for your OSS project tree. This is the painful part (as you would need to hunt down the details of specifying resources paths for various plugins involved depending on the OSS app type (i.e. web, etc.)). Good news is that this is a one time effort.
Once that is done, your main project can refer to the (wrapped) OSS project as a dependency. Here a (standard maven) multi-project structure would apply.
If OSS project has dependencies - create a POM with those dependencies (your project will use them as transitive dependencies) and install that artifact and pom in local repository. If OSS project hasn't any other dependencies is even simpler - the POM is generated automatically during installing.
For both cases use maven-install-plugin.
mvn install:install-file -Dfile=your-artifact-1.0.jar \
[-DpomFile=your-pom.xml] \
[-Dsources=src.jar] \
[-Djavadoc=apidocs.jar] \
[-DgroupId=org.some.group] \
[-DartifactId=your-artifact] \
[-Dversion=1.0] \
[-Dpackaging=jar] \
[-Dclassifier=sources] \
[-DgeneratePom=true] \
[-DcreateChecksum=true]

LATEST version of parent project in Maven

I am using Maven2. I have created a parent POM for my organization. I want the various groups will use it as a parent for their project but I want them to use the latest version.
for some reason, using it as a parent with version LATEST doesn't work,
any idea?
Thanks,
Ronen.
You don't need to define a new version for every small change you make in the POM.
The version means specific features of an artifact (in a POM are build settings), what I'd do is to declare one version and make all the projects use that version (to use a SNAPSHOT version is a great idea). If you make a small update do it in that version. If you make a bigger change you might want to declare a new version and have all the new POMs to use that version, this way you'll avoid to break old projects by using a new super POM.
Maven version plugin has a goal version:update-parent to set the parent version to the latest parent version.
Just execute
mvn versions:update-parent
in the project which you want to use latest parent version, it modifies the POM files for you.
I think you want to use SNAPSHOT, e.g.
<version>1.2-SNAPSHOT</version>
You need to run mvn with parameter -U in order to force the update of the local metadata files which hold the mappings for LATEST and RELEASE versions.

Maven2 inheritance

If I have a parent pom and want to inherit this to several projects. I usually do this by adding in top of the project <parent> ... </parent>. What I don't like about this approach is that if something changes in my parent I have to edit all project which are inherited by that parent to modify the version number. Is there a better approach? I hope it is understandable what I'm trying to explain.
Thanks in advance.
What i don't like about this approach
is that if something changes in my
parent i have to edit all project
which are inherited by that parent to
modify the version number. Is there a
better approach?
Yes there is! Have a look at the Maven Versions Plugin, specifically:
versions:update-child-modules updates the parent section of the
child modules of a project so the
version matches the version of the
current project.
For example, if you
have an aggregator pom that is also
the parent for the projects that it
aggregates and the children and parent
versions get out of sync, this mojo
can help fix the versions of the child
modules.
(Note you may need to invoke
Maven with the -N option in order to
run this goal if your project is
broken so badly that it cannot build
because of the version mis-match).
Edit: Of course, using Maven3 you can now have < version >-less < parent > elements in sub modules:
Developers working in multi-module or multi-pom projects won't have to specify the parent version in every sub-module in Maven 3. Instead, you can add version-less parent elements.
Ref
You can use the Maven Release Plugin when doing a release. It will update all the version numbers automatically and create a tag in your source control (if you have SCM configured in the POM).
My commands for performing a release are typically as follows, after which I export the tag from SCM and build it with "mvn clean package" or "mvn clean deploy".
svn update (or whatever SCM you use)
mvn clean
mvn release:prepare -DautoVersionSubmodules=true
mvn release:clean
So for example if you version is first "1.0-SNAPSHOT", then the release plugin will create a tag "projectname-1.0" with version "1.0", and finally increase the current version to "1.1-SNAPSHOT". The plugin will ask you for the versions and tag name, so you can override the defaults.
Automatic Parent versioning (i.e. omission of the tag) is a contentious issue in the Maven space. There is a defect logged against it. For now, it is being considered as a fix or improvement in the 2.1 version branch,
You should keep your versions as snapshots until it's time to release. This way you won't have to change it every time you change the pom. However once you've released a parent pom, you will want to make the change to all the children (assuming the parent is outside the "reactor" build...otherwise it would have been all bumped together by the release plugin). There is a relatively new plugin called the versions-maven-plugin that can assist with changing the versions.
I think the important thing to realize is that in a multi-module build, maven always uses the the version that is from your local repository. This applies in multi-module builds too! So when you reference the "parent" pom you're getting the published parent artifact from your local maven repository. So when you do mvn install you repeatedly publish each module to your local repo.
While developing, your own modules are probably versioned to something like X.X-SNAPSHOT. The reference to the parent-pom is X.X-SNAPSHOT. Don't change these before you're ready to release.
So a simple case would be:
Before initial release all modules are called 1.0-SNAPSHOT.
When makin the initial release "golden build", rename all 1.0-SNAPSHOT modules to 1.0.
When starting development on the 1.1 release, you change all version numbers to 1.1-SNAPSHOT.
And so on...
The custom is to work with snapshot versions until you're releasing, at which point you update the version numbers everywhere. In the day-to-day development you do not change the version numbers because snapshot-releases get treated differently than hard-version releases.
Edit:
After some thought I think some of your confusion in the "comments" section arises from this: The version number in your pom reflects the overall application version. Any given pom change does not necessarily change the application version number. If you need to track changes in the pom I would suggest you use a source control system. So in the 3 month period you work on version 1.0, it's reasonable to keep the version number at 1.0-SNAPSHOT. In the (for instance) 3 week period you work on 1.1, the version number is 1.1-SNAPSHOT.