I am reading sonatype's tutorial on multimodule projects and I see that in submodule they use the <pluginManagement> configuration like this:
<build>
<pluginManagement>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<configuration>
<testFailureIgnore>true</testFailureIgnore>
</configuration>
</plugin>
</plugins>
</pluginManagement>
</build>
This confuses me as I thought that <pluginManagement> is to be used in parent POM to provide common plugin configuration for submodules. What are the reasons for using plugin managment in children poms ?
Most of the time <pluginManagement> is used in parent pom files.
It configures plugins. But makes them not active part of the build. Therefor you need to add them to the <plugins> part of the Maven pom file. Most not done in parent pom files, but done in the (sub) modules, using / refering to that (parent) pom.
I think this is special to the use of the surefire plugin.
Since you execute the plugin with mvn test the surefire plugin will be executed with the configuration specified in the pluginManagement block. Other plugins are not executed directly but by binding them to another lifecycle phase and thus must be specified in the plugin block.
See the usage page of the surefire plugin.
Related
This is a snippet of my pom file.
....
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<version>2.4</version>
<executions>
<execution>
<phase>install</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
......
</configuration>
</execution>
</executions>
</plugin>
</plugins>
...
I use it successfully with the command
mvn install
But, when I try to enclose it into the "pluginManagement" tag, the maven-dependency-plugin stops working when I launch the install goal.
Why does the "pluginManagement" tag change the build behavior? Or should I use another goal or option?
You still need to add
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
</plugin>
</plugins>
in your build, because pluginManagement is only a way to share the same plugin configuration across all your project modules.
From Maven documentation:
pluginManagement: is an element that is seen along side plugins. Plugin Management contains plugin elements in much the same way, except that rather than configuring plugin information for this particular project build, it is intended to configure project builds that inherit from this one. However, this only configures plugins that are actually referenced within the plugins element in the children. The children have every right to override pluginManagement definitions.
The difference between <pluginManagement/> and <plugins/> is that a <plugin/> under:
<pluginManagement/> defines the settings for plugins that will be inherited by modules in your build. This is great for cases where you have a parent pom file and would like to avoid having to copy the same code for the configuration of the plugin over to each of these modules.
<plugins/> is a section for the actual invocation of the plugins. It may or may not be inherited from a <pluginManagement/>.
You don't need to have a <pluginManagement/> in your project, if it's not a parent POM. However, if it's a parent pom, then in the child's pom, you need to have a declaration like:
<plugins>
<plugin>
<groupId>com.foo</groupId>
<artifactId>bar-plugin</artifactId>
</plugin>
</plugins>
Notice how you aren't defining any configuration. You can inherit it from the parent, unless you need to further adjust your invocation as per the child project's needs.
For more specific information, you can check:
The Maven pom.xml reference: Plugins
The Maven pom.xml reference: Plugin Management
You use pluginManagement in a parent pom to configure it in case any child pom wants to use it, but not every child plugin wants to use it. An example can be that your super pom defines some options for the maven Javadoc plugin.
Not each child pom might want to use Javadoc, so you define those defaults in a pluginManagement section. The child pom that wants to use the Javadoc plugin, just defines a plugin section and will inherit the configuration from the pluginManagement definition in the parent pom.
pluginManagement: is an element that is seen along side plugins. Plugin Management contains plugin elements in much the same way, except that rather than configuring plugin information for this particular project build, it is intended to configure project builds that inherit from this one. However, this only configures plugins that are actually referenced within the plugins element in the children. The children have every right to override pluginManagement definitions.
From http://maven.apache.org/pom.html#Plugin%5FManagement
Copied from :
Maven2 - problem with pluginManagement and parent-child relationship
<pluginManagement> just like <dependencyManagement> are both used to share only the configuration between a parent and it's sub-modules.
For that we define the dependencie's and plugin's common configurations in the parent project and then we only have to declare the dependency/plugin in the sub-modules to use it, without having to define a configuration for it (i.e version or execution, goals, etc). Though this does not prevent us from overriding the configuration in the submodule.
In contrast <dependencies> and <plugins> are inherited along with their configurations and should not be redeclared in the sub-modules, otherwise a conflict would occur.
I know Maven compiler plugin by DEFAULT is bind to :
compile
test compile
life cycles, in general without specifying addition configuration, we don't have to
explicitly define it in our POM, but I still seen experienced developer putting things like
this in their POM, e.g
<build>
<plugins>
<plugin>
<artifactId>maven-shade-plugin</artifactId>
</plugin>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
</plugin>
</plugins>
</build>
I wander what's the point? and why is he doing this?
For the shade plugin, he is probably using POM inheritance. Look in the parent POM hierarchy for a pluginManagement section, there is probably shade plugin configuration there that he is pulling into this module.
For the compiler plugin, I do not know. You are correct, for jar/war/ear/ejb projects Maven will pull in the compiler config automatically, even if he has defined specific configuration in a parent POM's pluginManagement section.
If they put such things in their pom's they don't understand Maven. You should define the version of the plugins your are using in your build. This is done by:
<build>
<pluginManagement>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin<artifactId>
<version>3.1</version>
<configuration>
<target>1.6</target>
<source>1.6</source>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin<artifactId>
<version>2.3</version>
</plugin>
</plugins>
</pluginManagement>
</build>
This should be usually located into a pom file known under Company POM which defines versions of plugins for projects within a company.
Furthermore based on the life-cycle definition in Maven the Maven Super POM which contains the default bindings there you could see that particular plugins versions are defined.This means if you upgrade your Maven version you start using different plugin versions which is fact not the best related to build reproducibility. So the best practice is to define all used plugins like here as an example.. Based on the definition you shouldn't need to mention anything in your build-tag area if you have a defined packaging type (This is one of those Convention Over Configuration paradigm hints).
I use the findbugs-maven-plugin to check for bugs with maven. My maven project is a multi-module project that roughly looks as follows:
java-module
pom.xml
src/ ...
pom.xml
scala-module
pom.xml
src/ ...
I use Jenkins to build and test the project, and Jenkins runs goal findbugs:findbugs in the top-most directory. Since FindBugs reports many spurious warnings for code that is generated by the Scala compiler, I would like to tell FindBugs not to analyze the code in scala-module. However, when I run findbugs:findbugs in the top-most directory, it always analyzes all classes in java-module and scala-module. How can I tell maven to ignore scala-module as a whole? I know about FindBugs exclude filters but I would to have a configuration option for FindBugs that tells it to simply not analyze the code in a certain submodule.
FindBugs is configured in pom.xml in subdirectory java-module as follows:
<reporting>
<plugins>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>findbugs-maven-plugin</artifactId>
<version>${version.plugin.codehaus.findbugs}</version>
<configuration>
<findbugsXmlOutput>true</findbugsXmlOutput>
<findbugsXmlWithMessages>true</findbugsXmlWithMessages>
<xmlOutput>true</xmlOutput>
</configuration>
</plugin>
</plugins>
</reporting>
Despite the configuration being done only for the java-module, FindBugs will always also analyze scala-module.
Add a configuration the scala-module pom.xml that explicitly instructs findbugs to skip the module, i.e.
<reporting>
<plugins>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>findbugs-maven-plugin</artifactId>
<configuration>
<skip>true</skip>
</configuration>
</plugin>
</plugins>
</reporting>
Note that Maven often requires you to repeat boilerplate XML for cases like this.
Noahlz's answer did not work for me, but adding the following snippet to the sub-module's POM.xml did the trick.
<properties>
<findbugs.skip>true</findbugs.skip>
</properties>
I have a couple of projects, all using the same plugins in the build section.
Is it possible to specify which plugins to run inside the build section in a central place?
I know you can put the plugin configuration in a parent poms pluginManagement section, but then you still have to list all plugins in the build section.
For example I want something like:
parent.pom
<pluginManagement>
<plugins>
<plugin>
<artifactId>plugin1</artifactId>
...
</plugin>
<plugin>
<artifactId>plugin2</artifactId>
...
</plugin>
</plugins>
</pluginManagement>
child.pom
<build>
<include-plugins-from-parent-without-listing-plugin1-and-plugin2/>
</build>
Also, I would like to do the same thing with reports. Define in a single file which reports to run and include this in every other project.
Update: any other way of synchronizing the same build settings between multiple projects is fine too. I just do not want to copy&paste the same stuff in all POM files.
Inside parent.pom declare the plugins inside <build>\<plugins> instead of <pluginManagement>:
<build>
<plugins>
<plugin>
<artifactId>plugin1</artifactId>
...
</plugin>
</plugins>
</build>
I am attempting to make a maven parent pom setup where I don't have to declare any plugin information in my child pom, everything is taken from the parent pom.
I essentially have it working where I've put all my plugins with there configurations in to the parent pom. Then in the child poms I have to declare the plugin still, but without the version and configuration information.
I don't want to have to declare the plugin in the child at all. This way I can add new features (such as pmd, freebugs, etc) to my parent pom and all my projects now have them working. How can I accomplish this?
Parent Pom
<pluginManagement>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-scm-plugin</artifactId>
<version>1.0</version>
<inherited>true</inherited>
<configuration>
<providerImplementations>
<cvs>cvs_native</cvs>
</providerImplementations>
<systemProperties>
<property>
<name>maven.scm.perforce.clientspec.name</name>
<value>${perforceClientSpec}</value>
</property>
</systemProperties>
</configuration>
</plugin>
Child Pom still needs this but I don't want to have to do this if I can avoid it:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-scm-plugin</artifactId>
</plugin>
<pluginManagement> section is intended to configure project builds that inherit from this one. However, this only configures plugins that are actually referenced within the plugins element in the children (so you have to explicitly specify them, as you indicated). See more here.
If you want to avoid this, you can put this information into <build> section like this:
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-scm-plugin</artifactId>
<version>1.0</version>
<configuration>
<...>
</configuration>
<executions>
<...>
</executions>
</plugin>
</plugins>
</build>
Instead of using pluginManagement, try using just <plugins> tag. It should be auto inherited. You may optionally override configuration in child pom. Check that by mvn help:effective-pom
You can't avoid naming the plugin in the child pom, cause how should maven know which plugin are you using. The pluginManagement section is intended for defining the versions of plugin furthermore it's used to define a default configuration.