Tuesday, March 8, 2011

Getting Timestamp in Ant (trivial) and Maven (nontrivial)

I have been working on custom plug-ins for Ant and Maven to upload artifacts to a server. These are source files, the binaries and anything required for scanning using a static code analysis tool for security. Having used Ant for more than a decade now getting the time stamp to keep track of the uploads and also the log files was done in a few minutes.

So, it is trivial getting a timestamp from within my build.xml file. Attached is the sample for doing the same.

No surprises, and everything works like a charm.

Now comes the tough part. Getting the timestamp in Maven. After writing several plug-ins for Hudson and Sonar, I was thinking I have some good knowledge about Maven. I was completely wrong. I have been struggling getting the time stamp plug-in to work with Maven.

So, here are the steps I followed when I saw there was a "Build Number Maven Plug-in".

I added the plugin details to my pom.xml file. Attached are the details:

As soon as I ran this, I got an exception as shown below:

artifact org.codehaus.mojo:buildnumber-maven-plugin: checking for updates from central
[WARNING] repository metadata for: 'artifact org.codehaus.mojo:buildnumber-maven-plugin' could not be retrieved from repository: central due to an error: Error transferring file: Connection timed out: connect
Repository 'central' will be blacklisted
The plugin 'org.codehaus.mojo:buildnumber-maven-plugin' does not exist or no valid version could be found

Next, I decided to install the plug-in manually on my local repository. So, here I followed the following steps:

1. Downloaded the jar from http://mirrors.ibiblio.org/pub/mirrors/maven2/org/codehaus/mojo/buildnumber-maven-plugin/1.0-beta-4/buildnumber-maven-plugin-1.0-beta-4.jar

2. Installed it locally in my Maven repository as such:
mvn install:install-file -Dfile=buildnumber-maven-plugin-1.0-beta-4.jar \
-DgroupId=org.codehaus.mojo \
-DartifactId=buildnumber-maven-plugin \
-Dversion=1.0-beta-4 \

The timestamp was created at this point, and now the plugin complains about the scm url being null.

Storing buildNumber: 20110308095006 at timestamp: 1299595806804
The scm url cannot be null.
java.lang.NullPointerException: The scm url cannot be null.
at org.apache.maven.scm.manager.AbstractScmManager.makeScmRepository(AbstractScmManager.java:181)
at org.codehaus.mojo.build.CreateMojo.getScmRepository(CreateMojo.java:722)
at org.codehaus.mojo.build.CreateMojo.getScmBranch(CreateMojo.java:593)
at org.codehaus.mojo.build.CreateMojo.execute(CreateMojo.java:452)
at org.apache.maven.plugin.DefaultPluginManager.executeMojo(DefaultPluginManager.java:490)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoals(DefaultLifecycleExecutor.java:694)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoalWithLifecycle(DefaultLifecycleExecutor.java:556)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoal(DefaultLifecycleExecutor.java:535)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoalAndHandleFailures(DefaultLifecycleExecutor.java:387)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeTaskSegments(DefaultLifecycleExecutor.java:348)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.execute(DefaultLifecycleExecutor.java:180)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:328)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:138)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:362)
at org.apache.maven.cli.compat.CompatibleMain.main(CompatibleMain.java:60)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.codehaus.classworlds.Launcher.launchEnhanced(Launcher.java:315)
at org.codehaus.classworlds.Launcher.launch(Launcher.java:255)
at org.codehaus.classworlds.Launcher.mainWithExitCode(Launcher.java:430)
at org.codehaus.classworlds.Launcher.main(Launcher.java:375)
Total time: 2 seconds
Finished at: Tue Mar 08 09:50:07 EST 2011
Final Memory: 24M/224M

I searched the FAQ section of this plugin at http://mojo.codehaus.org/buildnumber-maven-plugin/faq.html and it says to include the
which like you can see I have included.

At this point, I just gave up using this plug-in.

Have you used this plug-in and have a work around for this problem? Please share your thoughts. Is there anything else easier I can use to get the time stamp?

Update: After several tries using many other plug-ins including the one for Groovy, I found a workaround for some other bug at the following location http://jira.codehaus.org/browse/MRESOURCES-99, and I was able to successfully get the time stamp I need. Huh, I need my 3 hours back Maven......


  1. ok. That was a good and short solution.

    We could also use gmaven plugin (and use groovy/java code to get timestamp) or use antrun plugin (and use ant tasks to get timestamp). Ofcourse, using the maven timestamp property is the best.

  2. Yes indeed. However, I couldn't get gmaven to work for some reason.

  3. I wrote a post on GMaven few days back. I think you can use it similarly to get timestamp and stick it in a property.


  4. Thanks so much, Raja. I will check your post. It would definitely help me in other tasks.

  5. A Maven TSTamp Plugin is available from Maven Central. Check out project's home page on java.net: http://java.net/projects/maventstampplugin