Ktor GraalVM Server Example

This repository contains an example project to build a ktor jvm server with GraalVM native-image.

Features

JSON Rest API (/api/v1/news)
Exposed DB persistence
H2 in-memory database
Micrometer + Prometheus monitoring
Automatic error handling
CallID plugin
Custom Logging Middleware (Ktor Application Plugin)

Required

Linux/MacOS
GraalVM installed and set as environment variable JAVA_HOME (sdkman easiest variant)
native-image installed (use gu) and reachable

Build & Run native image

Directly run with ./gradlew nativeRun
Compile
- ./gradlew nativeCompile
- Run with ./graal-server
Use option --native-quick-build or evironment variable GRAALVM_QUICK_BUILD=true for faster builds

Docker Image (not tested!)

Use Dockerfile for multistage native-image build.
Results image is minmal size based of scratch

Known Issues

Micrometer not working correct on native
Serialization is not working for native-image out of the box
- Follow this GitHub Issue for progress
- Somewhat workaround: Analyze reflection by running Jar with tracing mode
  - Run with tracing ./gradlew -Pagent run
    - Try to test all possible paths (also possible via running tests)
  - Copy tracing config ./gradlew metadataCopy --task run --dir src/main/resources/META-INF/native-image