Packaging Maven project
This step by step guide will show you how to package Maven project. Let’s start with probably simplest spec file possible.
Name: simplemaven
Version: 1.0
Release: 1%{?dist}
Summary: Simple Maven project
License: BSD
URL: http://www.example.com
Source0: http://www.example.com/simplemaven-1.0.tar.gz
BuildArch: noarch
BuildRequires: maven-local
%description
This is simple Maven project.
%package javadoc
Summary: Javadoc for %{name}
%description javadoc
This package contains the API documentation for %{name}.
%prep
%setup -q
%build
%mvn_build
%install
%mvn_install
%files -f .mfiles
%dir %{_javadir}/%{name}
%files javadoc -f .mfiles-javadoc
%changelog
* Mon Oct 14 2013 Michal Srb <msrb@redhat.com> - 1.0-1
- Initial packaging
The spec file above is a real world example how it may look like for simple Maven
project. Both %build
and %install
sections consist only of one line.
Another interesting lines:
10: BuildRequires: maven-local
All Maven projects need to have BuildRequires on maven-local
. They also need
to have Requires and BuildRequires on jpackages-utils
, but build system adds
these automatically. Package maintainer doesn’t need to list them explicitly.
31: %dir %{_javadir}/%{name}
By default, resulting JAR files will be installed in %{_javadir}/%{name}
,
therefore package needs to own this directory.
The build could fail from many reasons, but one probably most common is build failure due to missing dependencies
We can try to remove these missing dependencies from pom.xml and make Maven
stop complaining about them. However, these removed dependencies may be crucial
for building of the project and therefore it may be needed to package them
later. Let’s remove the dependencies from pom.xml
.
...
%prep
%setup -q
# Add following lines to %prep section of a spec file
%pom_remove_dep :commons-io
%pom_remove_dep :junit
Package maintainer can use a wide variety of “pom_” macros for modifying
pom.xml
files. See Macros for POM modification
section for more information.
Now try to build the project again. The build will fail with compilation failure.
Oops, another problem. This time Maven thought it had all the necessary dependencies, but Java compiler thinks otherwise.
Now it’s possible to either patch the source code not to depend on
missing libraries or to package them. Second approach is usually correct. It’s not necessary to package every
dependency right away. Maintainer could package compile time dependencies first and keep the
rest for later (test dependencies, …). But Maven needs to know that it shouldn’t try to run tests now. This can be achieved by passing -f
option to %mvn_build
macro. Maven
will stop complaining about missing test scoped dependencies from now on.
Equivalently it is also possible to disable the test phase without adding
a switch to Another switch |
It is always recommended to run all available test suites during build. It greatly improves quality of the package. |
We already have package which provides commons-io:commons-io
artifact, let’s add it to the BuildRequires
. Also disable tests for now.
BuildRequires: maven-local
BuildRequires: apache-commons-io
...
%prep
%setup -q
# Comment out following lines in %prep section
#%%pom_remove_dep :commons-io
#%%pom_remove_dep :junit
%build
# Skip tests for now, missing dependency junit:junit:4.11
%mvn_build -f
One can easily search for package which provides desired artifact. Try
|
Now try to build the project one more time. The build should succeed now. Congrats, you managed to create an RPM from Maven project!
There is plenty of other things maintainer may want to do. For example, he may want to provide symbolic links to the JAR file
in %{_javadir}
.
This can be easily achieved with %mvn_file
macro:
%prep
%setup -q
%mvn_file : %{name}/%{name} %{name}
See Alternative JAR File Names section for more information.
Another quite common thing to do is adding aliases to Maven artifact. Try to run rpm
-qp --provides
on your locally built RPM package:
$ rpm -qp --provides simplemaven-1.0-1.fc21.noarch.rpm
mvn(com.example:simplemaven) = 1.0
simplemaven = 1.0-1.fc21
The output above tells us that the RPM package provides Maven artifact "com.example:simplemaven:1.0". Upstream may change the groupId:artifactId with any new release. And it happens. For example org.apache.commons:commons-io changed to commons-io:commons-io some time ago. It’s not a big deal for package itself, but it is a huge problem for other packages that depends on that particular package. Some packages may still have dependencies on old groupId:artifactId, which is suddenly unavailable. Luckily, there is an easy way how to solve the problems like these. Package maintainer can add aliases to actually provided Maven artifact.
%mvn_alias org.example:simplemaven simplemaven:simplemaven
See Additional Mappings
for more information on %mvn_alias
.
Rebuild the pacakge and check rpm -qp --provides
output again:
$ rpm -qp --provides simplemaven-1.0-2.fc21.noarch.rpm
mvn(com.example:simplemaven) = 1.0
mvn(simplemaven:simplemaven) = 1.0
simplemaven = 1.0-2.fc21
Now it doesn’t matter if some other package depends on either of these listed artifact. Both dependencies will always be satisfied with your package.
One could try to fix dependencies in all the dependent packages instead of adding an alias to single package. It’s almost always wrong thing to do. |