4.5. Generating a Custom Offline Repository
Use case for a custom offline repository
When you move from the development phase of a project to the deployment phase, it is typically more convenient to pre-install all of the artifacts required by your application, rather than downloading them from the Internet on demand. In this case, the ideal solution is to create a custom offline repository, which contains the artifacts needed for your deployment. Creating a custom offline repository by hand, however, would be difficult, because it would need to include all of the transitive dependencies associated with your application bundles and features.
The ideal way to create a custom offline repository is to generate it, with the help of the Apache Karaf
features-maven-plugin
plug-in.
features-maven-plugin Maven plug-in
The
features-maven-plugin
plug-in from Apache Karaf is a utility that is used internally by the Apache Karaf developer community and the Red Hat JBoss Fuse development team to create distributions of the Apache Karaf OSGi container. Some of the goals of this plug-in are also useful for application developers, however, and this section explains how you can use the add-features-to-repo
goal to generate your own custom offline repository.
Important
At present, only the
add-features-to-repo
goal of the features-maven-plugin
plug-in is supported.
Steps to generate a custom repository
To generate and install a custom offline repository for specific Apache Karaf features, perform the following steps:
Create a POM file
In a convenient location—for example,
ProjectDir
—create a new directory, ProjectDir/custom-repo
to hold the Maven project. Using a text editor, create the project's POM file, pom.xml
, in the custom-repo
directory and add the following contents to the file:
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>org.acme.offline-repo</groupId> <artifactId>custom-repo</artifactId> <version>1.0.0</version> <name>Generate offline features repository</name> </project>
This is the bare bones of a Maven POM, which will be added to in the following steps. There is no need to specify a Maven package type here (it defaults to
jar
), because no package will be generated for this project.
Add the features-maven-plugin
Continue editing the
pom.xml
and add the features-maven-plugin
as shown (where the build
element is inserted as a child of the project
element):
<project ...> ... <build> <plugins> <plugin> <groupId>org.apache.karaf.tooling</groupId> <artifactId>features-maven-plugin</artifactId> <version>2.2.1</version> <executions> <execution> <id>add-features-to-repo</id> <phase>generate-resources</phase> <goals> <goal>add-features-to-repo</goal> </goals> <configuration> <descriptors> <!-- List the URLs of required feature repositories here --> </descriptors> <features> <!-- List features you want in the offline repo here --> </features> <repository>target/features-repo</repository> </configuration> </execution> </executions> </plugin> </plugins> </build> </project>
Subsequent steps will explain how to specify the descriptor list (of features repositories) and the features list.
Specify the features to download
In this example scenario, it is assumed that you want to make the
camel-jms
feature and the camel-quartz
feature available in offline mode. List all of the features you want to download and store in the offline repository in the features
element, which is a child of the configuration
element of the features-maven-plugin
.
To make the
camel-jms
and camel-quartz
features available offline, add the following features
element as a child of the feature-maven-plugin
's configuration
element:
<features> <feature>camel-jms</feature> <feature>camel-quartz</feature> </features>
Specify the feature repositories
A feature repository is a location that stores feature descriptor files. Generally, because features can depend recursively on other features and because of the complexity of the dependency chains, the project normally requires access to all of the standard Red Hat JBoss Fuse feature repositories.
To see the full list of standard feature repositories used by your installation of JBoss Fuse, open the
etc/org.apache.karaf.features.cfg
configuration file and look at the featuresRepository
setting, which is a comma-separated list of feature repositories, like the following:
... # # Comma separated list of feature repositories to register by default # featuresRepositories=mvn:org.apache.karaf/apache-karaf/2.1.3-fuse-00-00/xml/features, mvn:org.apache.servicemix.nmr/apache-servicemix-nmr/1.4.0-fuse-00-00/xml/features,mvn :org.apache.servicemix/apache-servicemix/4.3.1-fuse-00-00/xml/features,mvn:org.apache .camel.karaf/apache-camel/2.6.0-fuse-00-00/xml/features,mvn:org.apache.servicemix/ode -jbi-karaf/1.3.4/xml/features,mvn:org.apache.activemq/activemq-karaf/5.4.2-fuse-01-00 /xml/features ...
Now, add the listed feature repositories to the configuration of the
features-maven-plugin
in your POM file. Open the project's pom.xml
file and add a descriptor
element (as a child of the descriptors
element) for each of the standard feature repositories. For example, given the preceding value of the featuresRepositories
list, you would define the features-maven-plugin
descriptors list in pom.xml
as follows:
<descriptors> <!-- List taken from featuresRepositories in etc/org.apache.karaf.features.cfg --> <descriptor>mvn:org.apache.karaf/apache-karaf/2.1.3-fuse-00-00/xml/features</descriptor> <descriptor>mvn:org.apache.servicemix.nmr/apache-servicemix-nmr/1.4.0-fuse-00-00/xml/features</descriptor> <descriptor>mvn:org.apache.servicemix/apache-servicemix/4.3.1-fuse-00-00/xml/features</descriptor> <descriptor>mvn:org.apache.camel.karaf/apache-camel/2.6.0-fuse-00-00/xml/features</descriptor> <descriptor>mvn:org.apache.servicemix/ode-jbi-karaf/1.3.4/xml/features</descriptor> <descriptor>mvn:org.apache.activemq/activemq-karaf/5.4.2-fuse-01-00/xml/features</descriptor> </descriptors>
Specify the Red Hat JBoss Fuse system repository
Add the Red Hat JBoss Fuse system repository,
EsbInstallDir/system
, to the list of repositories in the pom.xml
file. This is necessary for two reasons: first of all, it saves you from downloading Maven artificats that are already locally available from your JBoss Fuse installation; and secondly, some of the artifacts in the system repository might not be available from any of the other repositories.
Using a text editor, open
pom.xml
and add the following repositories
element as a child of the project
element, customizing the file URL to point at your local system repository:
<project ...>
...
<repositories>
<repository>
<id>esb.system.repo</id>
<name>Red Hat JBoss Fuse internal system repo</name>
<url>file:///E:/Programs/FUSE/apache-servicemix-6.1.0.redhat-379/system</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
<releases>
<enabled>true</enabled>
</releases>
</repository>
</repositories>
...
</project>
Specify the remote repositories
Generally, the project requires access to all of the standard JBoss Fuse remote repositories. To see the full list of standard remote repositories, open the
etc/org.ops4j.pax.url.mvn.cfg
configuration file and look at the org.ops4j.pax.url.mvn.repositories
setting, which is a comma-separated list of URLs like the following:
org.ops4j.pax.url.mvn.repositories= \ http://repo1.maven.org/maven2, \ http://repo.fusesource.com/maven2, \ http://repo.fusesource.com/maven2-snapshot@snapshots@noreleases, \ http://repo.fusesource.com/nexus/content/repositories/releases, \ http://repo.fusesource.com/nexus/content/repositories/snapshots@snapshots@noreleases, \ http://repository.apache.org/content/groups/snapshots-group@snapshots@noreleases, \ http://repository.ops4j.org/maven2, \ http://svn.apache.org/repos/asf/servicemix/m2-repo, \ http://repository.springsource.com/maven/bundles/release, \ http://repository.springsource.com/maven/bundles/external
Each entry in this list must be converted into a
repository
element, which is then inserted as a child element of the respositories
element in the project's pom.xml
file. The preceding repository URLs have slightly different formats and must be converted as follows:
RepoURL
- The value of the repository URL,
RepoURL
, is inserted directly into theurl
child element of therepository
element. For example, thehttp://repo1.maven.org/maven2
repository URL translates to the followingrepository
element:<repository> <!-- 'id' can be whatever you like --> <id>repo1.maven.org</id> <!-- 'name' can be whatever you like --> <name>Maven central</name> <url>http://repo1.maven.org/maven2</url> <snapshots> <enabled>false</enabled> </snapshots> <releases> <enabled>true</enabled> </releases> </repository>
RepoURL@snapshots
- The
@snapshots
suffix indicates that downloading snapshots should be enabled for this repository. When specifying the value of theurl
element, remove the@snapshots
suffix from the URL. Change thesnapshots/enabled
flag totrue
, as shown in the following example:<repository> <id>IdOfRepo</id> <name>LongNameOfRepo</name> <url>RepoURL</url> <snapshots> <enabled>true</enabled> </snapshots> <releases> <enabled>true</enabled> </releases> </repository>
RepoURL@snapshots@noreleases
- The combination of the
@snapshots
suffix and the@noreleases
suffix indicates that downloading snapshots should be enabled and downloading releases should be disabled for this repository. When specifying the value of theurl
element, remove both suffixes from the URL. Change thesnapshots/enabled
flag totrue
and change thereleases/enabled
flag tofalse
, as shown in the following example:<repository> <id>IdOfRepo</id> <name>LongNameOfRepo</name> <url>RepoURL</url> <snapshots> <enabled>true</enabled> </snapshots> <releases> <enabled>false</enabled> </releases> </repository>
Generate the offline repository
To generate the custom offline repository, open a new command prompt, change directory to
ProjectDir/custom-repo
, and enter the following Maven command:
mvn generate-resources
Assuming that the Maven build completes successfully, the custom offline repository should now be available in the following location:
ProjectDir/custom-repo/target/features-repo
Install the offline repository
To install the custom offline repository in the JBoss Fuse container, edit the
etc/org.ops4j.pax.url.mvn.cfg
file and append the offline repository directory to the list of default repositories, as follows:
org.ops4j.pax.url.mvn.defaultRepositories=file:${karaf.home}/${karaf.default.repository}@snapshots,file:ProjectDir/custom-repo/target/features-repo@snapshots
The
@snapshots
suffix can be added to the offline repository URL, if there is a possibility that some of the artifacts in it are snapshot versions.