I need a best-practice solution for the following problem. I have a maven multi-module project with 3 subprojects:
client-module (simple java app which packaged as .jar)
module-1-that-uses-client
module-2-that-uses-client
module-*-that-uses-client is a bunch of static xml config files with a client-module.jar which is packaged as a .zip file. So, the packaged structure of a module-*-that-uses-client would look like:
client-module.jar
config1.xml
config2.xml
config3.xml
I wonder how I can implement following build strategies.
If I build client-module, then:
build client-module
copy client-module.jar to all module-*-that-uses-client
build all module-*-that-uses-client modules.
If I build any of module-*-that-uses-client, then:
build client-module
copy client-module.jar to exact module-*-that-uses-client
build exact module-*-that-uses-client modules.
Appreciate any help on this problem.
One solution would be the usage of --also-make and --also-make-dependents.
--also-make builds all dependencies of the specified module. Example: mvn --projects module-1-that-uses-client --also-make clean install builds client-module and module-1-that-uses-client in this order.
--also-make-dependents builds the specified module and all other modules with a dependency to the specified module. Example: mvn --projects client-module --also-make-dependents clean install builds first client-module and then both module-*-that-uses-client.
See also the Guide to Working with Multiple Modules.
Related
I have a question about how the Maven dependency resolving mechanism is working in a multi module project.
Normally I only use 'mvn clean install' when I build my multi module projects and my assumption was that if any module in the project needs a previous module, dependency will be resolved by going local repository and loading the corresponding 'jar'.
For project internal reason, I have to use 'mvn clean compile,' this command naturally does not create any 'jar' while 'install' is not there. So here I started wondering, how the dependency resolution for a multi module project works, while jar' is not created but project still able to see the changes from the previous builds. Does the target directories used for dependency management?
Or for 'mvn clean compile' target directory used but for 'mvn clean install' the local repository.
Can anybody explain me how the dependency resolution works in a 'multi module' project.
Thx for answers.....
I think you will understand better if you look at https://maven.apache.org/guides/introduction/introduction-to-the-lifecycle.html
There is a life cycle in the process of building the jar. The compile target will compile the code and create a complete classes folder in your target directory. This target will resolve all your dependencies in your poms and download any dependencies to your local repo, not already there.
The install target will create the jar from the classes directory and install it in your local repository.
I really think you will need to run the install target to get anything useful.
Maven is made of separate components.
There a component that deal with a given module and among other things try to get its dependencies. It ALWAYS get the dependencies from the local repository, eventually after having downloaded such dependencies. If the dependencies are not there and can't be dowloaded, it will fail. Eventually the module will create its own artifact that it will publish to the local repo.
Then there a compoment that when you ask it to build several maven modules, for example calling mvn at the root of a project does order the various module use the dependencies to find the best ordering for the build so that if a given module depend on another, it will be build after the module it depend on. It then call the previous compoent I described, building each module in order.
In all cases, a given module dependencies are always taken from the local repo. The expectation is that the previous modules that were built before actually pushed their artifact to the local repo typically with the mvn install but you could force it do it at any step thanks to proper configuration (may not be a good idea).
In all case if the previous component jar was not built and put into the repo, there no way such jar can be added in the classpath for the next module to be compiled.
Doing compile only on multiple projets isn't going to be any useful.
Is it possible to combine the capabilities of an archetype and a normal Maven plugin into a single plugin?
I have a custom language which I can compile into Java source code. I've written a Maven plugin which does this in the generate-sources phase, adds the Java source to the project, and builds the project. It works as I'd expect.
However, to use it, I need to first write out a pom.xml file referencing my plugin and describing where the input files live. I'd like to be able to go straight from raw input files to compiled code in a single maven command.
For example, suppose I have this directory structure:
my-project/
some-input-file.dsl
I want to run
bash$ mvn com.waisbrot.plugin:generate -DgroupID=com.waisbrot package
and after Maven's done running have:
my-project/
some-input-file.dsl
pom.xml
target/
generated-sources/
plugin/
SomeInputFile.java
classes/
com/
waisbrot/
SomeInputFile.class
some-input-file-1.0.jar
Actually, the integration testing of the archetype allows you to declare the parameter and goals. So do this:
Pick the template project you want to create
mvn archetype:create-from-project. It will create a new archetype
Review src/test/resources/projects, especially goal.txt and archetype.properties (source: http://maven.apache.org/archetype/maven-archetype-plugin/integration-test-mojo.html). Tweak so install will be implicity
mvn verify will be able to build the archetype, run the it, and get it installed
Hope it helps
I have a multi module maven project. One of the modules is a reusable part which is packaged into a jar, and the other is a war web-app which depends on the first module. When I use jetty:run-exploded on the second module, the packaged jar is taken from local maven repository whereas I want the first module to be rebuild and packaged into the resulting war. Is there any way to force such behavior instead of the default one?
From everything I can tell from reading documents about Maven's design and using Maven myself this cannot be done in the projects own directory.
Maven will not follow module paths UP a hierarchy. Using -amd (also make dependencies) will only work at the top level module that ties all the other multi-module pom's together. So what you can do is this:
At the TOP level directory
mvn -amd -pl jetty_module jetty:run-exploded
I think you can use maven Advanced Reactor Options to archive this.
http://www.sonatype.com/people/2009/10/maven-tips-and-tricks-advanced-reactor-options/
The -pl or –projects option allows you to select a list of projects from a multimodule project. This option can be useful if you are working on a specific set of projects, and you’d rather not wait through a full build of a multi-module project during a development cycle.
Maven -amd(also-make-dependents ) also help to build multi module project once. Using that you can build a project and any project that depends on that project.
I have two projects as follows, in neighbouring directories on the filesystem:
project_a (-SNAPSHOT)
project_b (-SNAPSHOT, depends on project_a)
I'd like to build project_b and for Maven to discover that project_a exists on the filesystem and thus build it rather than look in the local repo for its artifact.
I could build these within an aggregator and use the reactor to select project_b i.e.
mvn --projects project_b [goal]
However, this is problematic because
this two-project example is a simplification of my real build, which consists of dozens of projects, and I don't want to have to maintain an aggregator project that lists all of them.
I only want to recursively build -SNAPSHOT dependencies
Is there a neat way I could get Maven to perform a recursive build that looks on the filesystem to find -SNAPSHOT dependency projects and builds them?
I needed this a while back and made a simple recursive wrapper cli in nodejs. https://github.com/kenglxn/mvnr/blob/master/README.md
Install from npm with
sudo npm install -g mvnr
Then just pass any maven command to mvnr, and it will run that command on all mvn projects under the cwd.
You could play with Maven Reactor plugin, e.g. try mvn reactor:make -Dmake.folders=foo,bar
I am probably missing something but how is the maven ear plugin (I'm using version 2.5) resolving ejbModule dependencies? I have the following structure:
my-parent (multimodule)
-- pom.xml
-- myEar
-----pom.xml
---myEjb
-----pom.xml
In the ear I have the dependency to myEjb.
2 things that are unexpected when i execute mvn package under myEar
It does not build (package) myEjb.
It does try to resolve the depedency to myEjb via repository, which is in our case our custom sonar repository that we configured in settings.xml. I would like not to have to install myEjb to our custom sonar respository in a separate step.
What I expected from the plugin would be: check the ejbModules dependencies, build and package them if not done or something changed, copy the jar to the target directory of the ear project and package the whole thing correctly.
Obviously I am missing something though, anybody can enlighten me?
Based on your structure you have to build from the root of your project which means you have to change to my-parent directory
my-parent (multimodule)
-- pom.xml
-- myEar
-----pom.xml
---myEjb
-----pom.xml
and do
mvn clean package
The behaviour you described that maven tries to solve the dependencies against your local repository is the usual process. You can do partialy building a single module within a multi-module build but in your case this won't work cause you depend on your myEjb which neeeds to be rebuilded. Otherwise you can do a
mvn install
first and after that you can do from the root:
mvn -pl myEjb clean test
which will only build the myEjb module and uses the dependencies from the repository (localy in this case).