CODEWITHSUNDEEP
maven-2
Sean Patrick Floyd
Sean Patrick Floyd

Reputation: 298898

Maven variable for reactor root

In a multi-module maven project, is there a variable that points to the root project folder?

but is there a variable that always points to the root directory (the one from which the maven command was executed), no matter from which project inside the reactor?

I realized that the problem I wanted to solve is pretty much unsolvable. I wanted a variable that pointed to either project.basedir, project.parent.basedir, project.parent.parent.basedir etc, whichever is higher. But since a project's parent pom need not be it's parent in the file system, my whole approach won't help. So I am accepting Pascal's answer because it answers my question (even if my question does not solve my problem).

Upvotes: 65

Views: 55573

Answers (7)

sparkyd
sparkyd

Reputation: 560

Use directory-maven-plugin with directory-of goal.

Unlike other suggestions:

  • This solution works for multi-module projects.
  • It works whether you build the whole project or a sub-module
  • It works whether you run maven from the root folder or a sub-module (unlike ${session.executionRootDirectory}
  • There's no need to set a relative path property in each and every sub-module!

The plugin lets you set a property of your choice to the absolute-path of any of the project's modules. In my case I set it to the root module... In my project root pom:

 <plugin>
    <groupId>org.commonjava.maven.plugins</groupId>
    <artifactId>directory-maven-plugin</artifactId>
    <version>0.1</version>
    <executions>
        <execution>
            <id>directories</id>
            <goals>
                <goal>directory-of</goal>
            </goals>
            <phase>initialize</phase>
            <configuration>
                <property>myproject.basedir</property>
                <project>
                    <groupId>com.my.domain</groupId>
                    <artifactId>my-root-artifact</artifactId>
                </project>
            </configuration>
        </execution>
    </executions>
</plugin>

From then on, ${myproject.basedir} in any sub-module pom always has the path of the project root module. And of course, you can set the property to any module, not just the root...

Upvotes: 7

Mateusz Stefek
Mateusz Stefek

Reputation: 3846

In the latest maven, you can use ${maven.multiModuleProjectDirectory}.

Upvotes: 45

Mikalai Parafeniuk
Mikalai Parafeniuk

Reputation: 1356

For me, there was a need for root directory during variable interpolation, not for plugins section - for local directory relative to root with hand-crafted jars. I know this is a bad practice to have local directory with jars, but this was a requirement of project.

Why I was unable to use different solutions:

  • ${session.executionRootDirectory} and ${user.dir} are tied with directory from which maven command was executed. I want to refer to the same directory independently of directory, from which maven was launched.
  • ${project.basedir} ,as mentioned above, points to current project directory, so child modules will search for jars in wrong location.
  • I had about 100 projects, so defining relative paths or usage of accepted answer for this question is quite complex in my case.
  • Directory plugin can be used only for plugin configurations, not for variable interpolation

So, in my case with bad requirements I have used environment variable which refers project root and used it in pom.xml. Use it as last resort, when other solutions do not work. Here is example, how I use environment variable in my case:

<repositories>
    <repository>
        <id>local-maven-repo</id>
        <!--NOTE: export PROJECT_ROOT=<location>-->
        <url>file:///${env.PROJECT_ROOT}/local-repo</url>
    </repository>
</repositories>

Upvotes: 5

Andrejs
Andrejs

Reputation: 27687

Such property can be created using: directory-maven-plugin. Using the plugin's highest-basedir goal you can assign the root path to any property you specify.

Upvotes: 6

ctrueden
ctrueden

Reputation: 6992

In Maven 3, ${session.executionRootDirectory} is "a variable that always points to the ... directory ... from which the maven command was executed."

Note that this is distinct from a property that gives the top-level root directory of a multi-module project, regardless of where in the directory structure mvn is executed from. Such a property does not exist to my knowledge, but you can use the ${basedir}/.. hack to achieve it. See this thread on maven-users for more details.

See also: Finding the root directory of a multi module maven reactor project

Upvotes: 25

Pascal Thivent
Pascal Thivent

Reputation: 570365

is there a variable that always points to the root directory (the one from which the maven command was executed)

user.dir (the working directory) should be that directory.

Upvotes: 49

G&#225;bor Lipt&#225;k
G&#225;bor Lipt&#225;k

Reputation: 9776

As far I think, there is no such variable. There are only workaround like in accepted answer of Maven2 property that indicates the parent directory .

Upvotes: 2

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