Update a Maven project version from script - maven-2

First of all, I do have some sort of understanding that the following might not be the generally accepted way to do things.
We have a Maven 2 project that has a version number which should be updated each week or so, during a new release. During this process, I've tried to eliminate all the things one has to remember and I've made a bash script that handles the process interactively.
However, my problem is updating the pom version from the command line. I can do this with sed but I don't think it is very convenient. I was wondering if there is any maven plugin that would be able to modify the pom.xml directly from the command line. The version is set in the properties section of the pom. Would it be possible to write a plugin that would change the properties?
Thanks in advance.
Update
It seems that my issue was with project versions defined as properties (that were applied when filtering) which seems now a bit dumb.
One thing that I'm still looking for an answer is how to get the version of certain project reliably to the command line. Previously I had a "pretty unique" property that I got using grep, but now the <version> element is not unique as in child project there is at least two of these. I would need some sort of XML parser if Maven has no solutions, but my goal is to make the script as independent as possible.
I'm not sure if I should've created a new question from this, but I didn't. Getting the version is very closely related to the setting the version.

I was wondering if there is any maven plugin that would be able to modify the pom.xml directly from the command line.
The Versions Maven Plugin can do this. Check the following goal:
versions:set can be used to set the project version from the command line, updating the details of any child modules as necessary.

From Maven POM reference:
env.X: Prefixing a variable with
"env." will return the shell's
environment variable. For example,
${env.PATH} contains the PATH
environment variable. Note: While
environment variables themselves are
case-insensitive on Windows, lookup of
properties is case-sensitive. In other
words, while the Windows shell returns
the same value for %PATH% and %Path%,
Maven distinguishes between
${env.PATH} and ${env.Path}. As of
Maven 2.1.0, the names of environment
variables are normalized to all
upper-case for the sake of
reliability.
That means that you can have an environment variable like $MYMAVENPROJECTVERSION and read it as this:
<version>${env.MYMAVENPROJECTVERSION}</version>
You can update this environment variable every week, before running build.
Hope this will help you.

Related

QuickBuild: How can I create a builder to open a tarball package (tar.gz) whose name will change with each version?

I'm using PMEase QuickBuild to perform automated builds of our Maven2 projects and a nightly sanity test to ensure nothing is broken.
The test needs to untar packages which are created by the automated Maven2 projects. The problem is that the package names change frequently due to project versions being incremented all the time.
Does anyone know how I can configure QuickBuild to pick up the version (ideally from the POM file of the individual components), if this is possible at all?
I don't know if this is an option for you but it looks like you can do it the other way around. Quoting Build with Maven:
Control build version
If you want to control the build
version from QuickBuild side, please
follow below steps:
Change the POM file and define the project version as
${buildVersion}. Do not forget to
commit the file into your SCM after
change.
Define a build property like below when define the Maven build
step:
buildVersion=${build.version}
There are maybe other options but I must admit that my knowledge (zero) of QuickBuild is very limited
I created a work around to this issue by having QuickBuild execute a shell script which did the untarring by using wildcards, similar to the following (to avoid computing the exact version):
tar xzf filename-*.tar.gz
I couldn't figure out how to do this in QuickBuild, so I offloaded the work to the shell script.

Running Maven Goals in CLI

I have a maven pom.xml file with multiple instances of a same goal defined (inside <execution> with different <id>s).
I'm wondering how I can run a specific goal via maven command line. I've tried mvn --help, but I couldn't find an entry regarding this.
Answering my own question is always fun, especially the answer is "no, you can't do it."
After many Google searches, I've encountered the following article:
http://docs.codehaus.org/display/MAVENUSER/Default+Plugin+Execution+IDs
There is no way to separate configurations for command line executions of different goals in the same plugin.
Currently, the main plugin configuration section can be used to define settings to be used when executing a plugin from the command line. Unfortunately, these settings are applied to all executions of the plugin.
Having read your own answer, I'm not sure I understood the question :) But it sounds like this previous question and answer.

Maven - installing artifacts to a local repository in workspace

I'd like to have a way in which 'mvn install' puts files in a repository folder under my source (checkout) root, while using 3rd party dependencies from ~/.m2/repository.
So after 'mvn install', the layout is:
/work/project/
repository
com/example/foo-1.0.jar
com/example/bar-1.0.jar
foo
src/main/java
bar
src/main/java
~/.m2/repository
log4j/log4j/1.2/log4j-1.2.jar
(In particular, /work/project/repository does not contain log4j)
In essense, I'm looking for a way of creating a composite repository that references other repositories
My intention is to be able to have multiple checkouts of the same source and work on each without overwriting each other in the local repository with 'install'. Multiple checkouts can be because of working on different branches in cvs/svn but in my case it is due to cloning of the master branch in git (in git, each clone is like a branch). I don't like the alternatives which are to use a special version/classifier per checkout or to reinstall (rebuild) everything each time I switch.
Maven can search multiple repositories (local, remote, "fake" remote) to resolve dependencies but there is only ONE local repository where artifacts get installed during install. It would be a real nightmare to install artifacts into specific locations and to maintain this list without breaking anything, that would just not work, you don't want to do this.
But, TBH, I don't get the point. So, why do you want to do this? There might be alternative and much simpler solutions, like installing your artifacts in the local repository and then copying them under your project root. Why wouldn't this work? I'd really like to know the final intention though.
UPDATE: Having read the update of the initial question, the only solution I can think of (given that you don't want to use different versions/tags) would be to use two local repositories and to switch between them (very error prone though).
To do so, either use different user accounts (as the local repository is user specific by default).
Or update your ~/.m2/settings.xml each time you want to switch:
<settings xmlns="http://maven.apache.org/SETTINGS/1.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.0.0
http://maven.apache.org/xsd/settings-1.0.0.xsd">
<localRepository>${user.home}/.m2/repository</localRepository>
<!--localRepository>${user.home}/.m2/repository2</localRepository-->
...
</settings>
Or have another settings.xml and point on it using the --settings option:
mvn install --settings /path/to/alternate/settings.xml
Or specify the alternate location on the command line using the -Dmaven.repo.local option:
mvn -Dmaven.repo.local=/path/to/repo
These solutions are all error prone as I said and none of them is very satisfying. Even if you might have very good reasons to work on several branches in parallel, your use case (not rebuilding everything) is not very common. Here, using distinct user accounts migh be the less worse solution IMO.
This is INDEED possible with the command line, and in fact is quite useful. For example, if you want to create an additional repo under your Eclipse project, you just do:
mvn install:install-file -DlocalRepositoryPath=repo \
-DcreateChecksum=true -Dpackaging=jar \
-Dfile=%2 -DgroupId=%3 -DartifactId=%4 -Dversion=%5
It's the "localRepositoryPath" parameter that will direct your install to any local repo you want.
I have this in a batch file that I run from my project root, and it installs the file into a "repo" directory within my project (hence the % parameters). So why would you want to do this? Well, let's you say you are professional services consultant, and you regularly go into customer locations where you are forced to use their security hardened laptops. You copy your self-contained project to their laptop from a USB stick, and presto, you can do your maven build no problem.
Generally, if you are using YOUR laptop, then it makes sense to have a single local repo that has everything in it. But to you who got cocky and said things like "why would you want to do that", I have some news...the world is a bigger place with more options than you might realize. If you are using laptops that are NOT yours, and you need to build your project on that laptop, get the resulting artifact, and then remove your project directory (and the local repo you just used), this is the way to go.
As to why you would want to have 2 local repos, the default .m2/repository is where the companies standard stuff goes, and the local "in project" repo is where YOUR stuff goes.
This is not possible with the command line client but you can create more complex repository layouts with a Maven repository server like Nexus.
The reason why it's not possible is that Maven allows to nest projects and most of them will reference each other, so installing each artifact in a different repository would lead to lots of searches on your local hard disk (or to failed builds when you start a build in a sub-project).
FYI: symlinks work in Windows7 and above so this kind of thing is easy to achieve if all your code goes in the same place in the local repo, i.e /com/myco/.
type mklink for details
I can see that you do not want to use special versions or classifiers but that is one of the best solutions to solve this problem. I work on the same project but different versions and each mvn install takes half an hour to build. The best option is to change the pom version appended with the change name, for example 1.0.0-SNAPSHOT-change1 that I'm working on thereby having multiple versions of the same project but with different code base.
It has made my life very easy in the long run. It helps run multiple builds at the same time without issues. Even during SCM push, we can skip the pom file from staging so there can always be 2 versions for you to work on.
In case you have a huge project with multiple sub-modules and want to change all the versions together, you can use the below command to do just that
mvn versions:set -DnewVersion=1.0.0-SNAPSHOT-change1 -DprocessAllModules
And once done, you can revert using
mvn versions:revert
I know this might be not what you are looking for, but it might help someone who wants to do this.

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.

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.