Maven offline - problem with mvn-plugins

Question

I'm using maven in my project and I need to run the build in a non-internet-access machine.

When I test my project build everything is working, but when I run the build in a future moment, the maven try to update the mvn-plugins and this sht* is broking my build.

My config file: settings.xml from mvn.

    <profile>
      <id>blaProfile</id>
      <repositories>
        <repository>
          <id>blaRepo</id>
          <url>file://${bla.3rdParty.home}/maven/.m2/repository</url>
          <layout>default</layout>
        </repository>
      </repositories>
      <pluginRepositories>
        <pluginRepository>
          <id>blaRepo</id>
          <url>file://${bla.3rdParty.home}/maven/.m2/repository</url>
          <layout>default</layout>
        </pluginRepository>
      </pluginRepositories>
    </profile>

  <activeProfiles>
    <activeProfile>blaProfile</activeProfile>
  </activeProfiles>

And I ran my maven is with the params:

mvn -npu -bla.3rdParty.home="$(THE_CORRECT_PATH)" package

I saw that maven try to update some mvn-plugins for some time, but the option:

-npu,--no-plugin-updates      Suppress upToDate check for any relevant

Should work for this updates.

Well waiting some help on that!

Thanks in advance!

---

UPDATE(1):
What I'm looking at, is that I could use the setting:

<usePluginRegistry>true</usePluginRegistry>

Inside my settings.xml and with this, I'll have a plugin-registry.xml inside ${user.home}/.m2 that I can config and force the maven plugins versions.

But it's not working! :(

Answer 1

Before you go offline run the following:

mvn dependency:go-offline

That will download all your dependencies and plugins that you need to build your project into ~/.m2/repository.

Once you've run that you can now build your project offline using the '-o' flag:

mvn install -o

Answer 2

In order to cache plugins into the .m2/repository folder you would need to specify all plugins explicitly with the mvn <maven-plugin-name>:help

You would also need to specify explicit version for each plugin in the <plugins> or <pluginsManagement> section of your pom.xml

<plugin> 
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-surefire-plugin</artifactId>
  <version>2.19</version>
  <dependencies>
    <dependency>
      <groupId>org.apache.maven.surefire</groupId>
      <artifactId>surefire-testng</artifactId>
      <version>2.19</version>
    </dependency>
  </dependencies>
</plugin>

This is needed to make sure that mvn install -o uses the same plugin version.

Ofcourse you would also need to run mvn dependency:go-offline to take care of your compile and test dependencies.

mvn assembly:help compiler:help enforcer:help exec:help failsafe:help install:help jar:help resources:help surefire:help mvn dependency:go-offline mvn compile --offline

Answer 3

It should suffice to run a mvn clean install on your code. The next time, when you run it in an offline mode you can use the following options:

mvn -Dmaven.repo.local=..\repository –o clean install

-o tells maven not to try to update its dependencies over the network and with -Dmaven.repo.local you provide the path of the repository which contains all the required dependencies. Alternatively, you can add the path of the repository in your settings.xml in the localRepository tag and add an <offline>true</offline>. You can configure the same in your Maven Eclipse configurations.

Answer 4

I think this happens because Maven hasn't got the metadata available locally to determine if its plugin versions are correct. If you specify exact versions for your plugins (which is a good idea for reproducability anyway), it doesn't need to do the check, so will not try to connect to the remote repositories.

By specify exact versions, I mean that in your project's POM you should add the version to the plugin declaration. For example:

<plugins>
  <plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-dependency-plugin</artifactId>
    <!-- set the version explicitly-->
    <version>2.0</version>
  </plugin>
</plugins>

Note you can also force Maven to use internal repositories instead of Central by setting up repository mirrors. See this answer for more details on using repository managers and mirrors.

In the config you included, you're setting your remote repository to point to your local repository, this is not a good idea. To run offline you should either pass -o at the command line or add this to your settings.xml:

<offline>true</offline>