README.md

Gradle Plugins

Bnd includes Gradle plugins for Gradle users to build Bnd projects in Bnd Workspace builds as well as in non-Bnd Workspace builds. A typical Gradle build is a non-Bnd workspace build. A Bnd Workspace build uses the information specified in the Bnd Workspace's cnf/build.bnd file and each project's bnd.bnd file to configure the Gradle projects and tasks.

The biz.aQute.bnd.gradle jar contains the Bnd Gradle Plugins. These plugins require Java 17 and at least Gradle 7.3 for Java 17, at least Gradle 7.5 for Java 18, and at least Gradle 7.6 for Java 19.

This README represents the capabilities and features of the Bnd Gradle Plugins in the branch containing this README. So for the master branch, this will be the latest development SNAPSHOT build. See the appropriate Git tag for the README for the Bnd Gradle Plugin version you are using.

Gradle Plugin for non-Bnd Workspace Builds

Bnd offers Gradle support for building bundles in typical Gradle build environments. There are two ways this support can be used. You can apply the biz.aQute.bnd.builder plugin to your project and/or you can use the new task types:

• Bundle
• Baseline
• Resolve
• Export
• TestOSGi
• Index
• Bndrun

Using Bnd Builder Gradle Plugin

To make the Bnd Builder Gradle Plugin available to your build, use the following in settings.gradle:

pluginManagement {
  plugins {
    id "biz.aQute.bnd.builder" version "7.1.0"
  }
}

The Gradle marker plugins for the Bnd Gradle plugins are also in Maven Central. So you may use Maven Central as a pluginManagement repository.

Apply the biz.aQute.bnd.builder plugin to your project

To apply the biz.aQute.bnd.builder plugin to your project, use the following in build.gradle:

plugins {
  id "biz.aQute.bnd.builder"
}

This plugin extends the normal java plugin by:

• Extending the jar task by adding a bundle extension. The jar task actions are also extended to use Bnd to generate a bundle. The bundle will contain all the content configured into the jar task plus whatever additional content is included via the Bnd instructions. The bndfile property of the task's bundle extension is set to file("bnd.bnd") if a bnd.bnd file exists in the project folder.
• Adds a baseline configuration.
• Adds a baseline task of type Baseline which baselines the bundle generated by the jar task against the prior version of that bundle in the repositories.

If you don't want to apply the plugin to the project but just need to use the task types, you can access the types with:

plugins {
  id "biz.aQute.bnd.builder" apply false
}

Gradle Configuration Cache Support

By default, the tasks of the Gradle Plugin for non-Bnd Workspace Builds use the Gradle Project object at task execution time to allow the Bnd instructions to resolve macro references such as ${project.group} which evaluates to the value of the group property of the Gradle Project object. However, Gradle's Configuration Cache support requires that a Gradle Project object cannot be used at task execution time. To prevent a task of the Gradle Plugin for non-Bnd Workspace Builds from using the Gradle Project object at task execution time, the task's properties property must be set to some value. This can be simply done by setting it empty. For example:

tasks.named("jar") {
  bundle {
    properties.empty()
  }
}

If you need to reference some project properties in the Bnd instructions and still use the Configuration Cache, then you will need to put the needed project properties in the task's properties property. For example:

tasks.named("jar") {
  bundle {
    properties.put("project.group", provider({project.group}))
  }
}

This sets the project.group key in the properties property to the value of a provider which returns the value of the project's group property. A provider is used for late binding of the value.

Create a task of the Bundle type

The Bundle task type is an extension of the Jar task type that adds a bundle extension with properties and uses Bnd to generate a bundle. The bundle will contain all the content configured into the task plus whatever additional content is included via the Bnd instructions. For example:

import aQute.bnd.gradle.Bundle

tasks.register("bundle",  Bundle) {
  from sourceSets.main.output
}

In either usage mode, the following bundle extension properties, in addition to the Jar task properties, can be configured.

bndfile

The bnd file to use to create the bundle. If this property is not set or the bnd file does not exist, then the bnd property will be used.

bnd

The Bnd instructions to use to create the bundle. This property is ignored if the bndfile property refers to a file that exists. If the bndfile property is not set or does not refer to a file that exists, or this property is not set, this is OK. But without some instructions to Bnd, your bundle will not be very interesting.

sourceSet

The SourceSet object to use for the Bnd builder. The default value is ${project.sourceSets.main}. You will only need to specify this property if you want to use a different SourceSet or the default SourceSet does not exist.

classpath

The FileCollection object to use as the classpath for the Bnd builder. The default value is ${project.sourceSets.main.compileClasspath}. You will only need to specify this property if you want to specify additional classpath elements or replace the classpath.

properties

Properties that are available for evaluation of the Bnd instructions. The default is the properties of the Gradle task and project objects.

Example

import aQute.bnd.gradle.Bundle

configurations {
  bundleCompile
}
sourceSets {
  bundle
}
tasks.register("bundle", Bundle) {
  from sourceSets.bundle.output
  bundle {
    bndfile = file("bundle.bnd")
    sourceSet = sourceSets.bundle
    classpath = sourceSets.bundle.compileClasspath
  }
}

Instructing Bnd on how to build your bundle

The normal way to instruct Bnd on how to build the bundle is to use a bnd file. This file will specify the Bnd instructions like -exportcontents, etc. You can also use the bnd property of the bundle extension. It can be used in several different ways. You can configure the bnd property with a multiline string:

jar {
  bundle {
    bnd '''
-exportcontents: com.acme.api.*
-sources: true
-include: other.bnd
'''
  }
}

You can also configure the bnd property with map notation:

jar {
  bundle {
    bnd("-exportcontents": "com.acme.api.*",
      "-sources": "true",
      "-include": "other.bnd")
  }
}

Finally, you can also use the manifest property to instruct Bnd. For example:

jar {
  manifest {
    attributes("-exportcontents": "com.acme.api.*",
      "-sources": "true",
      "-include": "other.bnd")
  }
}

You can even use a combination of the manifest property and a bundle extension property. But the bundle extension property takes priority over the manifest property. So if the same instruction is in both places, the one in the bundle extension property will be used and the one in the manifest property will be ignored.

Replacing use of Gradle's deprecated OSGi Plugin

In Gradle 5.0, the OSGi Plugin was deprecated. If you used the OSGi Plugin and want to switch to the Bnd Gradle Plugin, you will need to modify your build scripts. In addition to applying the biz.aQute.bnd.builder plugin to replace the OSGi Plugin, you will need to change usage of the OSGiManifest's instruction property to use the bnd property.

For example:

jar {
  manifest { // the manifest of the default jar is of type OsgiManifest
    name = "overwrittenSpecialOsgiName"
    instruction "Bundle-Vendor", "MyCompany"
    instruction "Bundle-Description", "Platform2: Metrics 2 Measures Framework"
    instruction "Bundle-DocURL", "https://www.mycompany.com"
  }
}

becomes:

jar {
  bundle {
    bnd("Bundle-Name": "overwrittenSpecialOsgiName",
      "Bundle-Vendor": "MyCompany",
      "Bundle-Description": "Platform2: Metrics 2 Measures Framework",
      "Bundle-DocURL": "https://www.mycompany.com")
  }
}

Use of the convenience properties on OSGiManifest must be replaced with the specifying the actual OSGi manifest header name in the Bnd instructions. For example, name = "overwrittenSpecialOsgiName" is replaced with bnd "Bundle-Name: overwrittenSpecialOsgiName".

Create a task of the Baseline type

The Baseline task type will baseline a bundle against a different version of the bundle. For example:

import aQute.bnd.gradle.Baseline

configurations {
  baseline
}
dependencies {
  baseline("group": group, "name": jar.archiveBaseName) {
    version {
      strictly "(0,${jar.archiveVersion.get()}["
    }
    transitive = false
  }
}
tasks.register("baseline", Baseline) {
  bundle = jar
  baseline = configurations.baseline
}

The following properties can be configured for a Baseline task:

ignoreFailures

If true the build will not fail due to baseline problems; instead an error message will be logged. Otherwise, the build will fail. The default is false.

baselineReportDirName

The name of the baseline reports directory. Can be a name or a path relative to the project's reporting.baseDirectory. The default name is baseline.

baselineReportDirectory

The baseline reports directory. The default is ${project.reporting.baseDirectory.dir(baselineReportDirName)}.

reportFile

The baseline report file. The default is ${baselineReportDirectory.file("${task.name}/${bundlename}.txt")}.

bundle

The bundle to be baselined. It can be anything that ConfigurableFileCollection.files(Object...) can accept to result in a single file. Typically this will be the task that builds the bundle. This property must be set.

baseline

The baseline bundle. It can be anything that ConfigurableFileCollection.files(Object...) can accept to result in a single file. Typically this will be a configuration that contains the earlier version of the bundle to baseline against. This property must be set.

diffpackages

The names of the exported packages in the bundle to baseline. The default is all the exported packages but this property can be used to specify which exported packages are baselined.

diffignore

The manifest header names and resource paths to ignore when baseline comparing. This property can be used to exclude items from baseline comparison.

For example, to exclude bundle versions from baseline comparison, add Bundle-Version to diffignore.

Create a task of the Resolve type

The Resolve task type will resolve a standalone bndrun file and set the -runbundles property in the file. For example:

import aQute.bnd.gradle.Resolve

def resolveTask = tasks.register("resolve", Resolve) {
  bndrun = file("my.bndrun")
  outputBndrun = layout.buildDirectory.file("my.bndrun")
}

The following properties can be configured for a Resolve task:

ignoreFailures

If true the task will not fail due to resolution failures; instead an error message will be logged. Otherwise, the task will fail. The default is false.

failOnChanges

If true the task will fail if the resolve process changes the value of the -runbundles property. The default is false.

writeOnChanges

If true the task will write changes to the value of the -runbundles property. The default is true.

bndrun

The bndrun file to be resolved. This property must be set.

outputBndrun

This is the output file for the calculated -runbundles property. The default is the input bndrun file which means the input bndrun file will be updated in place. If the output file is set to a different file than the input bndrun file, the generated output file will -include the input bndrun file and can be thus be used by other tasks, such as TestOSGi, as a resolved input bndrun file.

workingDirectory

The directory for the resolve process. The default is ${temporaryDir}.

bundles

The collection of files to use for locating bundles during the resolve process. The default is ${project.sourceSets.main.runtimeClasspath} plus ${project.configurations.archives.artifacts.files}. This property must not be used for and is ignored in Bnd Workspace builds.

reportOptional

If true failure reports will include optional requirements. The default is true.

properties

Properties that are available for evaluation of the Bnd instructions. The default is the properties of the Gradle task and project objects. This property must not be used for and is ignored in Bnd Workspace builds.

Create a task of the Export type

The Export task type will export a standalone bndrun file. For example:

import aQute.bnd.gradle.Export

tasks.register("export", Export) {
  bndrun = file("my.bndrun")
}

The following properties can be configured for an Export task:

ignoreFailures

If true the task will not fail due to export failures; instead an error message will be logged. Otherwise, the task will fail. The default is false.

exporter

Bnd has two built-in exporter plugins. bnd.executablejar exports an executable jar and bnd.runbundles exports the -runbundles files. The exporter plugin with the specified name must be an installed exporter plugin. The default is bnd.executablejar.

bndrun

The bndrun file to be exported. This property must be set.

destinationDirectory

The directory for the output.

workingDirectory

The directory for the export operation. The default is ${temporaryDir}.

bundles

The collection of files to use for locating bundles during the bndrun export. The default is ${project.sourceSets.main.runtimeClasspath} plus ${project.configurations.archives.artifacts.files}. This property must not be used for and is ignored in Bnd Workspace builds.

properties

Properties that are available for evaluation of the Bnd instructions. The default is the properties of the Gradle task and project objects. This property must not be used for and is ignored in Bnd Workspace builds.

Create a task of the TestOSGi type

The TestOSGi task type will execute tests in a standalone bndrun file. This example uses the output bndrun file from the Resolve task example above:

import aQute.bnd.gradle.TestOSGi

tasks.register("testOSGi", TestOSGi) {
  bndrun = resolveTask.flatMap { it.outputBndrun }
}

The following properties can be configured for a TestOSGi task:

ignoreFailures

If true the task will not fail due to test case failures; instead an error message will be logged. Otherwise, the task will fail. The default is false.

bndrun

The bndrun file to be tested. This property must be set.

workingDirectory

The directory for the test execution. The default is ${temporaryDir}.

bundles

The collection of files to use for locating bundles during the bndrun execution. The default is ${project.sourceSets.main.runtimeClasspath} plus ${project.configurations.archives.artifacts.files}. This property must not be used for and is ignored in Bnd Workspace builds.

tests

The list of fully qualified names of test classes to run. If not set, or empty, then all the test classes listed in the Test-Classes manifest header are run. The --tests command line option can be used to set the fully qualified name of a test class to run. This can be repeated multiple times to specify multiple test classes to run.

Use a colon (:) to specify a test method to run on the specified test class.

resultsDirectory

The directory for the test results. The default is ${project.java.testResultsDir}/${task.name}.

javaLauncher

Specify the default java executable to be used for execution. This java launcher is used if the bndrun does not specify the java property or specifies it with the default value java.

properties

Properties that are available for evaluation of the Bnd instructions. The default is the properties of the Gradle task and project objects. This property must not be used for and is ignored in Bnd Workspace builds.

Create a task of the Index type

The Index task type will generate an index for a set of bundles. For example:

import aQute.bnd.gradle.Index

tasks.register("index", Index) {
  destinationDirectory = layout.buildDirectory.dir("libs")
  gzip = true
  bundles = fileTree(destinationDirectory) {
    include "**/*.jar"
    exclude "**/*-sources.jar"
    exclude "**/*-javadoc.jar"
    builtBy tasks.withType(Jar)
  }
}

The following properties can be configured for an Index task:

gzip

If true, then a gzip'd copy of the index will be made with a .gz extension. Otherwise, only the uncompressed index will be made. The default is false.

indexName

The name of the index file. The file is created in the destinationDirectory. The default isindex.xml.

repositoryName

The name attribute in the generated index. The default is the name of the task.

destinationDirectory

The destination directory for the index. The default value is ${project.layout.buildDirectory}.

base

The URI base for the generated index. The default value is the file: URI of destinationDirectory.

bundles

The bundles to be indexed. It can be anything that ConfigurableFileCollection.files(Object...) can accept. This property must be set.

indexUncompressed

The output file for the uncompressed index. The default value is ${destinationDir}/${indexName}.

indexCompressed

The output file for the compressed index. The default value is ${destinationDir}/${indexName}.gz.

Create a task of the Bndrun type

The Bndrun task type will execute a bndrun file. For example:

import aQute.bnd.gradle.Bndrun

tasks.register("run", Bndrun) {
  bndrun = file("my.bndrun")
}

The following properties can be configured for a Bndrun task:

ignoreFailures

If true the task will not fail due to execution failures; instead an error message will be logged. Otherwise, the task will fail. The default is false.

bndrun

The bndrun file to be executed. This property must be set.

workingDirectory

The directory for the execution. The default is ${temporaryDir}.

bundles

The collection of files to use for locating bundles during the bndrun execution. The default is ${project.sourceSets.main.runtimeClasspath} plus ${project.configurations.archives.artifacts.files}. This property must not be used for and is ignored in Bnd Workspace builds.

javaLauncher

Specify the default java executable to be used for execution. This java launcher is used if the bndrun does not specify the java property or specifies it with the default value java.

properties

Properties that are available for evaluation of the Bnd instructions. The default is the properties of the Gradle task and project objects. This property must not be used for and is ignored in Bnd Workspace builds.

Gradle Plugins for Bnd Workspace Builds

The Bnd Gradle Plugins for Bnd Workspace builds uses the information specified in the Bnd Workspace's cnf/build.bnd file and each project's bnd.bnd file to build the projects.

The Bnd Gradle Plugins for Bnd Workspace builds consists of two plugins:

• The biz.aQute.bnd.workspace Gradle plugin can be applied in the settings.gradle file or the Bnd Workspace folder's build.gradle file.
• The biz.aQute.bnd Gradle plugin is applied to each subproject that is a Bnd project. The biz.aQute.bnd.workspace Gradle plugin will automatically apply the biz.aQute.bnd Gradle plugin to the Gradle projects for all the identified Bnd Workspace projects.

Bnd Workspace

A Bnd Workspace is a folder containing a cnf project as well as a number of peer folders each holding a Bnd project. So the Bnd Workspace folder is the main project of the Gradle build for the Bnd Workspace. The following files are in the root project:

• gradle.properties - Some initial properties to configure the Gradle build for the workspace.
• settings.gradle - Initializes the projects to be included in the Gradle build for the workspace.
• build.gradle - Configures the Gradle build for the workspace.

When creating a new Bnd Workspace with Bndtools, it will put these files on the root folder of the workspace.

These files can be modified to customize the overall Gradle build for the Bnd Workspace. If special Gradle build behavior for a project is needed, beyond changes to the project's bnd.bnd file, then you should place a build.gradle file in the project folder and place your customizations in there.

Using Bnd Gradle Plugins for Bnd Workspace builds

If you are using the Gradle build added by Bndtools when creating the the Bnd Workspace, you don't need to do anything else.

If you want to use the Bnd Gradle Plugins in your existing Gradle build, there are two approaches you can take. The main approach is to edit settings.gradle as follows:

plugins {
  id "biz.aQute.bnd.workspace" version "7.1.0"
}

The Gradle marker plugins for the Bnd Gradle plugins are also in Maven Central. So you may use Maven Central as a pluginManagement repository.

When you apply the biz.aQute.bnd.workspace Gradle plugin in the settings.gradle file, the plugin will determine the Bnd project folders in the Bnd Workspace, include them in the Gradle build, and apply itself to the root project. This will result in the biz.aQute.bnd Gradle plugin being applied to each project which is a Bnd project. With this approach, you don't even need a build.gradle file for the root project. But you can use a build.gradle file in the root project to apply common configuration across all your Bnd projects:

subprojects {
  if (plugins.hasPlugin("biz.aQute.bnd")) {
    // additional configuration for Bnd projects
  }
}

The second approach, for when you already have a settings.gradle file which includes the desired projects and you don't want the set of projects to include to be computed, is to put the plugins block in the root project's build.gradle file:

plugins {
  id "biz.aQute.bnd.workspace" version "7.1.0"
}

While this is the same as the previous settings.gradle example, since it is the root project's build.gradle file, it requires that your settings.gradle file has already included the necessary projects in the Gradle build. The plugin will apply the biz.aQute.bnd Gradle plugin to each Gradle project which is a Bnd project.

In general, your Gradle scripts will not apply the biz.aQute.bnd Gradle plugin directly to a project since this is handled by using the biz.aQute.bnd.workspace Gradle plugin in the settings.gradle file or the build.gradle file in the root project.

Gradle Configuration Cache Not Supported

The tasks of the Gradle Plugin for Bnd Workspace Builds use the Bnd Workspace model objects such as Workspace and Project at task execution time to perform Bnd operations. However, Gradle's Configuration Cache support requires that all objects used at task execution time must be serializable and the Bnd Workspace model objects are not serializable. So the Gradle Plugin for Bnd Workspace Builds cannot be used with Gradle's Configuration Cache.

Gradle Tasks

The biz.aQute.bnd Gradle Plugin extends the standard Gradle Java plugin. It modifies some of the standard Java plugin tasks as necessary and also adds some additional tasks. Running gradle tasks --all in a project will provide a complete list of the tasks available within the project.

The dependencies for the project are configured from the path information specified in the bnd.bnd file such as -buildpath and -testpath. These paths are then used by various tasks such as compileJava and compileTestJava.

The jar task uses Bnd to build the project's bundles.

The test task runs any plain JUnit tests in the project.

The check task runs all verification tasks in the project, including test and testOSGi.

Additional Tasks

The jarDependencies task jars all projects the project depends on.

The buildDependencies task assembles and tests all projects the project depends on.

The release task releases the project's bundles to the -releaserepo, if one is configured for the project.

The releaseDependencies task releases all projects the project depends on.

The releaseNeeded task releases the project and all projects it depends on.

The testOSGi task runs any OSGi JUnit tests in the project's bnd.bnd file by launching a framework and running the tests in the launched framework. This means the bnd.bnd file must have the necessary -runfw and -runbundles to support the test bundles built by the project. The check task depends on the testOSGi task.

The checkDependencies task runs the check task on all projects the project depends on.

The checkNeeded task runs the check task on the project and all projects it depends on.

The cleanDependencies task cleans all projects the project depends on.

The cleanNeeded task cleans the project and all projects it depends on.

The export.name tasks, one per bndrun file in the project, exports the name.bndrun file to an executable jar.

The export task will export all the bndrun files to executable jars.

The runbundles.name tasks, one per bndrun file in the project, creates a distribution of the -runbundles of the name.bndrun file.

The runbundles task will create distributions of the runbundles for all the bndrun files.

The resolve.name tasks, one per bndrun file in the project, resolves the name.bndrun file and updates the -runbundles instruction in the file.

The resolve task resolves all the bndrun files and updates the -runbundles instruction in each bndrun file.

The run.name tasks, one per bndrun file in the project, runs the name.bndrun file.

The testrun.name tasks, one per bndrun file in the project, runs the OSGi JUnit tests in the name.bndrun file.

The echo task will display some help information on the dependencies, paths and configuration of the project.

The bndproperties task will display the Bnd properties of the project.

Customizing a project's Gradle build

If you do need to write a build.gradle file for a Bnd project, there are some properties of the Bnd Gradle Plugins you will find useful.

• The bndWorkspace property of the project for the Bnd Workspace contains the Workspace object.
• The bnd.project property of the project contains the Project object.

Bnd properties for a project can be accessed in several ways. Given the example Bnd property name foo, you can use the bnd extension, bnd.get("foo", "defaultValue"), or directly bnd.foo. To access Bnd properties without any macro processing you can use the unprocessed function, bnd.unprocessed("foo", "defaultValue").

Using other JVM languages with the Bnd Gradle Plugins for Bnd Workspace builds

When you use the Gradle plugin for another JVM language like Groovy, Scala, or Kotlin with your Bnd Workspace build, the Bnd Gradle Plugin will configure the language's srcDirs for the main and test source sets to use the Bnd source and test source folders.

---

Using the latest development SNAPSHOT build of the Bnd Gradle Plugins

If you want to try the latest development SNAPSHOT build of the Bnd Gradle Plugins, you will need to refer to the snapshot repository and select the latest version (+) of the plugin. For example, replace the pluginManagement block (in settings.gradle) with a buildscript script block, to configure the repository and version of the plugin jar:

buildscript {
  repositories {
    maven {
      url = uri("https://bndtools.jfrog.io/bndtools/libs-snapshot")
    }
  }
  dependencies {
    classpath "biz.aQute.bnd:biz.aQute.bnd.gradle:+"
  }
}

Then replace the plugins block to use the apply plugin: syntax to apply the plugin. For example:

apply plugin: "biz.aQute.bnd.workspace"

If you want to use the latest development SNAPSHOT version on a regular basis, you will need to also need to add the following to the buildscript block to ensure Gradle checks more frequently for updates:

buildscript {
  ...
  /* Since the files in the repository change with each build, we need to recheck for changes */
  configurations.classpath {
    resolutionStrategy {
      cacheChangingModulesFor 30, "minutes"
      cacheDynamicVersionsFor 30, "minutes"
    }
  }
  dependencies {
    components {
      all { ComponentMetadataDetails details ->
        details.changing = true
      }
    }
  }
}

Remember, if you are using the Gradle daemon, you will need to stop it after making the change to use the development SNAPSHOT versions to ensure Gradle stops using the prior version of the plugin.

Using the latest Milestone/Release Candidate build of the Bnd Gradle Plugins

If you want to try the latest milestone or release candidate build of the Bnd Gradle Plugins, you will need to refer to the release repository, https://bndtools.jfrog.io/bndtools/libs-release, and select the desired version of the plugin. This can be done as above for the SNAPSHOT builds or via the pluginManagement section (in settings.gradle). For example:

pluginManagement {
  plugins {
    id "biz.aQute.bnd.builder" version "6.0.0-M1"
  }
  repositories {
    maven {
      url = uri("https://bndtools.jfrog.io/bndtools/libs-release")
    }
  }
}

---

For full details on what the Bnd Gradle Plugins do, check out the source code.