manifest first OSGi build with gradle - migrating from ant to Gradle

Question

Is there manifest first http://wiki.osgi.org/wiki/Tooling_Approaches gradle plugin for OSGi? Or how to do it with gradle?

There's big old project for OSGi container with many project having complicated relation declared in MANIFEST.MF. The build is long. Now we want to simplify things and adopt Gradle. But first without breaking things and keeping ant and gradle builds in parallel for some time. However what I see is gradle suggesting define MANIFEST inside build.gradle. https://docs.gradle.org/current/userguide/osgi_plugin.html
That would make a lot of copy work.

UPDATE There are close to 100 modules with a lot of dependencies information between modules and for nested jar. On average MANIFEST.MF length is about 50 lines (varies from 20 to 300 lines). How to bundle nested jar's is other question. This question is about using existing MANIFEST.MF files. All plugins I saw use bnd that is exactly contrary to manifest first approach.

Answer 1

Gradle has an OsgiManifest class, which is an extended jar manifest:

https://docs.gradle.org/current/javadoc/org/gradle/api/plugins/osgi/OsgiManifest.html

There is a post on StackOverflow that shows similar usage:

How to add Import-Package instructions for runtime dependencies?

The relevant gradle block looks like this:

apply plugin: 'java' apply plugin: 'osgi'  jar {     baseName = 'awesome'     manifest {         name = 'An Awesome Application'         symbolicName = 'com.example.awesome'         instruction 'Import-Package', 'org.springframework.orm', '*'     } } 

If you have existing manifests and would like to use your own custom files, you can do this by setting the manifest file location within the jar closure:

jar {     manifest {         def manif = "${resourcesDir}/MANIFEST.MF"         if (new File(manif).exists()) {             from file(manif)         }         else{             name = 'overwrittenSpecialOsgiName'             instruction 'Private-Package', 'org.mycomp.somepackage'             instruction 'Bundle-Vendor', 'MyCompany'             instruction 'Bundle-Description', 'Platform2: Metrics'          }     } } 

The documentation for Gradle's manifest can be found here: https://docs.gradle.org/current/javadoc/org/gradle/api/java/archives/Manifest.html

For your 'other question':

There are additional Gradle plugins for building OSGI bundles, in some cases, including dependencies from other OSGI bundles.

For one example, there is the Gradle Bundle Plugin, which uses the bnd tool and allows you to specify to include transitive-dependencies and even exclude unwanted ones. As an example:

jar {     manifest {         attributes 'Implementation-Title': 'Bundle Quickstart',     // Will be added to manifest                      'Import-Package': '*'  // Will be overwritten by the instuctions below     } }  bundle {     includeTransitiveDependencies = true      instructions << [         'Bundle-Activator': 'foo.bar.MyBundleActivator',         'Import-Package': 'foo.*',         '-sources': true     ]      instruction 'Export-Package', '*' // Specify an individual instruction     instruction '-wab', '' } 

There is also the Gradle osgi-run plugin, which includes transitive dependencies by default:

dependencies {     // all your usual dependencies     ...      osgiRuntime( "your:dependency:1.0" ) {         transitive = false // transitive dependencies not included in OSGi runtime     } } 

Hopefully that's enough to get you going.

Answer 2

As of April 2016 there's no Manifest-first approach in Maven or Gradle build tools for OSGi.

While for Eclipse plugins (that are also valid OSGi bundles) there is maven/tycho build, that is standard within Eclipse Foundation, it is not really of help for general OSGi projects.

Oposite to Manifest-first is Manifest generation, and there is only one tool bnd, that initially was for manifest creation, then grew into full bundle jar builder and now has BndTools Eclipse integration, looking similar to Maven/Gradle integration managing dependencies.

I would recommend to keep bnd instructions in external standard bnd.bnd file and not to put it inside build script. *.bnd files are similar to usual Java .properties files, so in Eclipse IDE right-click, Open with -> Other ... select Properties File Editor check "Use this editor for.." and check "Use this editor for all '*.nbd' files"

For Gradle

• [Gradle OSGi Plugin] (standard, built-in)(https://docs.gradle.org/current/userguide/osgi_plugin.html) gives only manifest manipulation, so GRADLE-1107 "OSGi instruction Include-Resource not working" is open issue since 2010
• Gradle Bundle Plugin allows you to create OSGI bundles. Its main difference from the Gradle OSGI Plugin is that it uses the bnd tool to generate not only a manifest but a whole jar.
• osgi-run "Osgi-Run - A Gradle plugin to make the development of modular applications using OSGi completely painless"

For maven

• maven-bundle-plugin aka Apache Felix Maven Bundle Plugin (BND) is “Maven first” approach
• bnd-maven-plugin announce and 2 plugins comparison

All bnd-based tools are now collected on http://bnd.bndtools.org/chapters/700-tools.html

There are some examples in https://github.com/paulvi/OSGiBuildExamples

Note: link http://wiki.osgi.org/wiki/Tooling_Approaches has been in "The OSGi Community Wiki was unfortunately hacked and is currently unavailable. " status for more than a week, while this question was opened.

Sadly @Richard gave up too early to receive some thanks as well (for mentioning maven)