WinterTechForum / skybar

Skybar: Live code coverage engine

skybar

Skybar: Live code coverage engine

Skybar shows you a web UI of your java code with live-updating per-line execution counts.

For a convenient toy app to try it out with, see Skybar Demo.

Usage

Build the jar:

./gradlew

This will produce build/libs/skybar-[version]-all.jar. Use this jar as the argument to -javaagent in a java invocation. You'll also need to provide several config properties (see SkybarConfig for more info):

• skybar.instrumentation.classRegex: class name regex for classes to instrument. The name is slash-separated as in com/foo/bar/baz.
• skybar.webUi.port: port for web ui, defaults to 54321. Or use 0 to have it pick an available port.
• skybar.source.fsPath: filesystem path to source

These can be specified in a properties file that is specified in the skybar.config system property or SKYBAR_CONFIG env var, or specified one at a time with system properties. System props, env vars, and the ocnfig file's contents are checked in that order.

You can also specify them as environment variables in all-caps form with underscores instead of dots, e.g. SKYBAR_SOURCE_FSPATH.

Here's an example invocation using the skybar demo app:

java \
  -Dskybar.instrumentation.classRegex='com/skybar/demo/.*' \
  -Dskybar.webUi.port=4321 \
  -Dskybar.source.fsPath=../skybar-demo/src/main/java \
  -javaagent:path/to/skybar-1.0-SNAPSHOT-all.jar \
  -jar ../skybar-demo/target/skybar-demo-1.0-SNAPSHOT-jetty-console.war --headless

To use both the debugger together with skybar, you can include an -agentlib line as well, like:

java \
  -agentlib:jdwp=transport=dt_socket,address=localhost:9009,server=y,suspend=y \
  -javaagent:build/libs/skybar-1.0-SNAPSHOT-all.jar \
  ...

Once that's running, connect to http://localhost:4321 (change the port as needed if you're not using the default) and use your app. You should see live updates to the number of times each line of code is executed.

What's with the name?

This project started as a 1-day hackathon at WTF2015. We wanted to set the bar high, and the sky was the limit...