Add support for GraalVM

Note: This doesn't actually work yet. At the time of writing I'm seeing issues with Ktor not finding the application.conf file.

Dockerfile

@@ -1,4 +1,4 @@
-FROM openjdk:17-jdk as builder
+FROM ghcr.io/graalvm/graalvm-ce:ol9-java17-22.3.0-b2 as builder
 MAINTAINER William Brawner <me@wbrawner.com>
 
 RUN groupadd --system --gid 1000 gradle \
@@ -6,12 +6,12 @@ RUN groupadd --system --gid 1000 gradle \
 
 COPY --chown=gradle:gradle . /home/gradle/src
 WORKDIR /home/gradle/src
-RUN /home/gradle/src/gradlew --console=plain --no-daemon shadowJar
+RUN /home/gradle/src/gradlew --console=plain --no-daemon nativeCompile
 
-FROM openjdk:17-slim
+FROM quay.io/centos/centos:stream9
 EXPOSE 8080
 RUN groupadd --system --gid 1000 twigs \
     && useradd --system --gid twigs --uid 1000 --create-home twigs
-COPY --from=builder --chown=twigs:twigs /home/gradle/src/app/build/libs/twigs.jar twigs.jar
+COPY --from=builder --chown=twigs:twigs /home/gradle/src/app/build/native/nativeCompile/twigs /usr/local/bin/twigs
 USER twigs
-CMD /usr/local/openjdk-17/bin/java $JVM_ARGS -jar /twigs.jar
+CMD /usr/local/bin/twigs

app/build.gradle.kts

@@ -1,11 +1,11 @@
 import java.net.URI
-import java.util.*
 
 plugins {
     java
     kotlin("jvm")
     application
     alias(libs.plugins.shadow)
+    alias(libs.plugins.graalvm)
 }
 
 repositories {
@@ -51,3 +51,20 @@ tasks.shadowJar {
 tasks.getByName<Test>("test") {
     useJUnitPlatform()
 }
+
+graalvmNative {
+    binaries {
+        named("main") {
+            fallback.set(false)
+            verbose.set(true)
+
+            buildArgs.add("--initialize-at-build-time=io.ktor,kotlin")
+
+            buildArgs.add("-H:+InstallExitHandlers")
+            buildArgs.add("-H:+ReportUnsupportedElementsAtRuntime")
+            buildArgs.add("-H:+ReportExceptionStackTraces")
+
+            imageName.set("twigs")
+        }
+    }
+}

app/src/main/resources/META-INF/native-image/reflect-config.json

@@ -0,0 +1,29 @@
+[
+  {
+    "name": "kotlin.reflect.jvm.internal.ReflectionFactoryImpl",
+    "allDeclaredConstructors":true
+  },
+  {
+    "name": "kotlin.KotlinVersion",
+    "allPublicMethods": true,
+    "allDeclaredFields":true,
+    "allDeclaredMethods":true,
+    "allDeclaredConstructors":true
+  },
+  {
+    "name": "kotlin.KotlinVersion[]"
+  },
+  {
+    "name": "kotlin.KotlinVersion$Companion"
+  },
+  {
+    "name": "kotlin.KotlinVersion$Companion[]"
+  },
+  {
+    "name": "kotlin.internal.jdk8.JDK8PlatformImplementations",
+    "allPublicMethods": true,
+    "allDeclaredFields":true,
+    "allDeclaredMethods":true,
+    "allDeclaredConstructors":true
+  }
+]

build.gradle.kts

@@ -5,6 +5,7 @@ buildscript {
     repositories {
         mavenLocal()
         mavenCentral()
+        gradlePluginPortal()
     }
 
     dependencies {
@@ -28,6 +29,6 @@ allprojects {
     group = "com.wbrawner"
     version = "0.0.1-SNAPSHOT"
     tasks.withType<KotlinCompile> {
-        kotlinOptions.jvmTarget = "16"
+        kotlinOptions.jvmTarget = "17"
     }
 }

gradle/libs.versions.toml

@@ -1,5 +1,6 @@
 [versions]
 bcrypt = "0.9.0"
+graalvm = "0.9.19"
 hikari = "5.0.1"
 junit = "5.8.2"
 kotlin = "1.6.21"
@@ -42,6 +43,7 @@ ktor-server = [
 ]
 
 [plugins]
+graalvm = { id = "org.graalvm.buildtools.native", version.ref = "graalvm" }
 kotlin-jvm = { id = "org.jetbrains.kotlin.jvm", version.ref = "kotlin" }
 kotlin-serialization = { id = "org.jetbrains.kotlin.plugin.serialization", version.ref = "kotlin" }
 shadow = { id = "com.github.johnrengelman.shadow", version.ref = "shadow" }