softprops / cappi   0.1.1

MIT License GitHub

the sweetest sbt plugin your microbenchmarks will ever meet

Scala versions: 2.10
sbt plugins: 0.13


The sweetest sbt plugin your microbenchmarks will ever meet.

Cappi runs Caliper benchmarks


This project targets sbt version 0.13. If you should want 0.12 support drop me an issue

To install Cappi in your sbt project, add the following to your project's plugin configuration, typically in a project/plugins.sbt file.

resolvers += Resolver.url(

addSbtPlugin("me.lessis" % "cappi" % "0.1.1")

Then mix cappiSettings into your build defintion, typically in a build.sbt file.



Cappi will run your benchmarks, but it needs to know what they are first. By default, Cappi defines two tasks to run your bench marks benchmark and benchmarkOnly both scoped to the cappi task.

Resolving Benchmarks

In order to run benchmarks Cappi makes the assumption that you've named your benchmark in a source file with a name ending with "Benchmark.scala". Cappi will look for this under your src/test/scala directory. It makes the assumption that you are packaging your benchmarks in folders that mirror the scala package they are under.

For example, the class foo.BarBenchmark

package foo
class BarBenchmark extends {
 // ...

would be expected to be located in a file named src/test/scala/foo/BarBenchmark.scala

You can see the full list of resolved benchmark class names by running the following the the sbt REPL

show cappi::benchmarks

Alternatively, you can override the benchmarks setting in your build definition

(cappi.Keys.benchmarks in cappi.Keys.cappi) := Seq("foo.BazBenchmark")

Running Benchmarks

To run your benchmarks, simply run the following in the sbt REPL. This will run all benchmarks.


Alternatively you can run just a target benchmark with benchmarkOnly providing a fully qualified Benchmark class name.


Caliper on your classpath

To run benchmarks, you need to first write benchmarks. To write benchmarks you need caliper on your classpath. To remove the need for you doing this yourself, Cappi will add caliper to your test classpath. This make getting started a much smoother process.

To override the calpier version in use, "0.5-rc1" by default, override the caliperVersion setting.

caliperVersion in cappi := Some("custom-version")

If you do not wish to have Cappi add this to your test classpath for some reason, say your benchmarks are not actually under your test class path. Set the caliperVersion setting to None

caliperVersion in cappi := None


This plugin continues on the path that this plugin started.

Doug Tangren (softprops) 2013