build(cli): Support building a GraalVM native image

Author: sschuberth

cli/build.gradle.kts

@@ -1,7 +1,13 @@
+import java.nio.file.Files
+
+import org.graalvm.buildtools.gradle.tasks.BuildNativeImageTask
+
 plugins {
     id("stan-kotlin-conventions")
 
     application
+
+    alias(libs.plugins.graalvm)
 }
 
 application {
@@ -19,3 +25,55 @@ dependencies {
     implementation(libs.koinCore)
     implementation(libs.kotlinReflect)
 }
+
+graalvmNative {
+    toolchainDetection = System.getenv("GRAALVM_HOME") == null
+
+    metadataRepository {
+        enabled = true
+    }
+
+    // For options see https://graalvm.github.io/native-build-tools/latest/gradle-plugin.html.
+    binaries {
+        named("main") {
+            imageName = provider { application.applicationName }
+
+            buildArgs.addAll(
+                "--report-unsupported-elements-at-runtime",
+                "--parallelism=8",
+                "-J-Xmx16g"
+            )
+        }
+    }
+}
+
+tasks.named<BuildNativeImageTask>("nativeCompile") {
+    // Gradle's "Copy" task cannot handle symbolic links, see https://github.com/gradle/gradle/issues/3982. That is why
+    // links contained in the GraalVM distribution archive get broken during provisioning and are replaced by empty
+    // files. Address this by recreating the links in the toolchain directory.
+    val toolchainDir = System.getenv("GRAALVM_HOME")?.let { File(it) }
+        ?: options.get().javaLauncher.get().executablePath.asFile.parentFile.run {
+            if (name == "bin") parentFile else this
+        }
+
+    val toolchainFiles = toolchainDir.walkTopDown().filter { it.isFile }
+    val emptyFiles = toolchainFiles.filter { it.length() == 0L }
+
+    // Find empty toolchain files that are named like other toolchain files and assume these should have been links.
+    val links = toolchainFiles.mapNotNull { file ->
+        emptyFiles.singleOrNull { it != file && it.name == file.name }?.let {
+            file to it
+        }
+    }
+
+    // Fix up symbolic links.
+    links.forEach { (target, link) ->
+        logger.quiet("Fixing up '$link' to link to '$target'.")
+
+        if (link.delete()) {
+            Files.createSymbolicLink(link.toPath(), target.toPath())
+        } else {
+            logger.warn("Unable to delete '$link'.")
+        }
+    }
+}

gradle/libs.versions.toml

@@ -1,6 +1,7 @@
 [versions]
 composePlugin = "1.7.3"
 detektPlugin = "1.23.8"
+graalvmPlugin = "0.10.6"
 kotlinPlugin = "2.1.20"
 versionsPlugin = "0.52.0"
 
@@ -17,6 +18,7 @@ poiOoxml = "5.4.0"
 [plugins]
 compose = { id = "org.jetbrains.compose", version.ref = "composePlugin" }
 compose-compiler = { id = "org.jetbrains.kotlin.plugin.compose", version.ref = "kotlinPlugin" }
+graalvm = { id = "org.graalvm.buildtools.native", version.ref = "graalvmPlugin" }
 kotlinSerialization = { id = "org.jetbrains.kotlin.plugin.serialization", version.ref = "kotlinPlugin" }
 versions = { id = "com.github.ben-manes.versions", version.ref = "versionsPlugin" }