sling-graalvm

Experimenting with GraalVM to run a useful subset of Apache Sling modules, focusing on request processing, resource resolution and servlet resolution and execution for now.

See also SLING-8556.

To build and run the native version, setup GraalVM to get something like this:

java -version
openjdk version "1.8.0_212"
OpenJDK Runtime Environment (build 1.8.0_212-20190523183630.graal2.jdk8u-src-tar-gz-b03)
OpenJDK 64-Bit GraalVM CE 19.0.2 (build 25.212-b03-jvmci-19-b04, mixed mode)

Then install the native-image tool:

gu install native-image

And build with

export GRAALVM_HOME=$JAVA_HOME
mvn clean install -Pnative

And run with

./target/org.apache.sling.graalvm.experiments-1.0-SNAPSHOT-runner

At which point the server should work:

$ curl -s http://localhost:8080/sling/chouc/route
{
  "path": "/sling/chouc/route",
  "metadata": {
    "sling.resolutionPath": "/sling/chouc/route",
    "sling.resolutionPathInfo": "/sling/chouc/route"
  }
}

To run as a Docker container see the Dockerfile.native file.

The time-to-first-request utility can be used to measure the time needed by that container + our app to start up.

TODO

Running in quarkus:dev mode fails so far (“no SCR metadata found”), even if using

mvn clean compile bnd:bnd-process quarkus:dev

The native startup time is about 5 seconds on my box, but just a few milliseconds when runnning in a Docker image.