sbt plugin for adding java agents to projects
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README.md

sbt-javaagent

This sbt plugin adds Java agents to projects in a general way. It can enable agents in sbt-native-packager dists, as compile-time dependencies, in forked run, or in forked tests.

Plugin dependency

Add the plugin to your project/plugins.sbt:

addSbtPlugin("com.lightbend.sbt" % "sbt-javaagent" % versionNumber)

The version number is determined by the latest package, and can be deduced from the version.sbt file, i.e. if the version.sbt is 0.1.5-SNAPSHOT then the latest released version is probably 0.1.4. You can see the full version packages in the bintray repository:

https://dl.bintray.com/sbt/sbt-plugin-releases/com.lightbend.sbt/sbt-javaagent/scala_2.12/sbt_1.0/

Java agent

To add a Java agent to an sbt-native-packager distribution, enable the JavaAgent plugin on a project that also has JavaAppPackaging enabled, and then add the agent dependency using the javaAgents setting. For example:

lazy val distProject = project
  .in(file("somewhere"))
  .enablePlugins(JavaAgent, JavaAppPackaging)
  .settings(
    javaAgents += "com.example" % "agent" % "1.2.3"
  )

This will automatically resolve the agent module, bundle the agent artifact in the distribution, and add a -javaagent option to the start script.

Note: sbt-javaagent has a dynamic dependency on sbt-native-packager. You need to add sbt-native-packager separately.

Scopes

By default, sbt-javaagent will only add an agent to distributions. Agents can be optionally enabled for compile, run, or test.

The following scopes are supported:

  • dist — bundle the agent in production distributions and add a -javaagent option to start scripts
  • compile — add the agent as a provided dependency so that it's available on the compile classpath
  • runtime — automatically fork the run and add a -javaagent option
  • test — automatically fork tests and add a -javaagent option

The plugin can derive these scopes from module configurations.

For example, to add an agent to compile, to build against an API provided by an agent, use the compile or provided configuration:

javaAgents += "com.example" % "agent" % "1.2.3" % "compile"

Marking a dependency for compile will also automatically enable the agent for run as well.

To enable for run or tests, use the runtime or test configurations.

Multiple configurations can be specified. For example, the following will enable both compile and test (and implicitly run):

javaAgents += "com.example" % "agent" % "1.2.3" % "compile;test"

Note that in this case, the agent dependency is actually added under the provided configuration, so that a project can compile against the agent and then have the agent provided at runtime using a -javaagent option.

If the compile scope is not enabled, then the agent dependency is put under a special javaagent configuration so that it doesn't appear as a regular library dependency or on build classpaths.

Agent arguments

A Java agent can have an extra argument string added to it that is provided to the premain method in the agent. To add an argument string simply provide it to the JavaAgent constructor.

javaAgents += JavaAgent("com.example" % "agent" % "1.2.3" % "compile;test", arguments = "java_agent_argument_string")