graalwasm-spring-boot-photon

Photon with GraalWasm and Spring Boot Demo

This demo illustrates how GraalWasm can be used to embed Photon, a WebAssembly image processing library written in Rust, in a Spring Boot application. The demo also uses GraalJS to access the Photon module through the WebAssembly JavaScript API.

Preparation

Install GraalVM for JDK 23 and set the value of JAVA_HOME accordingly. We recommend using SDKMAN!. (For other download options, see GraalVM Downloads.)

sdk install java 23-graal

Run the Application

To start the demo, simply run:

./mvnw package spring-boot:run

When the demo runs, open the following URLs in a browser:

• http://localhost:8080/photo/default
• http://localhost:8080/photo/grayscale
• http://localhost:8080/photo/colorize
• http://localhost:8080/photo/fliph
• http://localhost:8080/photo/flipv

To compile the application with GraalVM Native Image, run:

./mvnw -Pnative native:compile
./target/demo

To use Profile-Guided Optimization, run the following commands:

# Compile and run instrumented image
./mvnw -Pnative,pgo-instrument native:compile
./target/demo-g1-pgo-instrument

# Produce some load, for example using https://github.com/rakyll/hey
hey -c 8 -z 2m http://localhost:8080/photo/flipv
# Quitting the demo-g1-pgo-instrument process will generate a profile file (default.iprof)

# Compile and run optimized image
./mvnw -Pnative,pgo native:compile
./target/demo-g1-pgo

Implementation Details

The DemoController uses a PhotonService to implement the /photo/{effectName} endpoint. This service accesses Photon objects that are pooled in a PhotonPool to check whether an effect for a given effectName exists before applying the effect to a sample image.

PhotonPool creates a Photon object for each available processor, which in turn holds a reference to the corresponding photonModule and an imageContent object. Both of these objects are from JavaScript and backed by the same Context. Note that the Context objects share the same Engine, to improve warmup and memory footprint.

Also note that the Photon JavaScript and WebAssembly modules as well as the sample images are downloaded when the demo is built with the wagon-maven-plugin Maven plugin (see pom.xml).

The DemoApplicationTests tests that applying the same effect on two copies of the same image yields the same result, regardless of the effect used. Run it with ./mvnw test.