From fa152a45e74cba4f7d0c6c70aa2e05e45ab7b0ee Mon Sep 17 00:00:00 2001
From: Yang <ychescale9@gmail.com>
Date: Fri, 8 Dec 2023 18:18:15 +1100
Subject: [PATCH] WIP - add RuntimeHints, and reflection bindings. `nativeRun`
 still failing.

Readings:
- https://www.graalvm.org/22.2/reference-manual/native-image/guides/use-native-image-gradle-plugin/
- https://docs.spring.io/spring-boot/docs/current/reference/html/native-image.html#native-image.advanced.custom-hints
- https://github.com/oracle/graalvm-reachability-metadata
- https://github.com/spring-projects/spring-boot/issues/34157
- https://docs.spring.io/spring-framework/reference/core/aot.html#aot.hints.register-reflection-for-binding
- https://docs.spring.io/spring-framework/reference/core/aot.html
- https://betterprogramming.pub/experience-in-migrating-an-application-to-native-image-with-spring-boot-3-422d15efa31
---
 build.gradle.kts                              | 20 ++++++++++++++++
 .../kstreamlined/backend/KSConfiguration.kt   | 12 +++++++++-
 .../backend/KStreamlinedRuntimeHints.kt       | 24 +++++++++++++++++++
 .../datafetcher/FeedEntryDataFetcher.kt       |  3 ++-
 4 files changed, 57 insertions(+), 2 deletions(-)
 create mode 100644 src/main/kotlin/io/github/reactivecircus/kstreamlined/backend/KStreamlinedRuntimeHints.kt

diff --git a/build.gradle.kts b/build.gradle.kts
index 6845fb5..33d7ed5 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -24,6 +24,26 @@ dependencyManagement {
 group = "io.github.reactivecircus.kstreamlined.backend"
 version = "0.0.1-SNAPSHOT"
 
+graalvmNative {
+    metadataRepository {
+        enabled.set(true)
+    }
+    binaries.configureEach {
+        resources.autodetect()
+    }
+    binaries.named("main") {
+        buildArgs(
+            "--strict-image-heap",
+            "-march=native",
+            "-R:MaxHeapSize=10m",
+        )
+        javaLauncher = javaToolchains.launcherFor {
+            languageVersion.set(JavaLanguageVersion.of(21))
+            vendor.set(JvmVendorSpec.GRAAL_VM)
+        }
+    }
+}
+
 tasks.withType<GenerateJavaTask>().configureEach {
     packageName = "io.github.reactivecircus.kstreamlined.backend.schema.generated"
 }
diff --git a/src/main/kotlin/io/github/reactivecircus/kstreamlined/backend/KSConfiguration.kt b/src/main/kotlin/io/github/reactivecircus/kstreamlined/backend/KSConfiguration.kt
index 2bf4bae..e13a92e 100644
--- a/src/main/kotlin/io/github/reactivecircus/kstreamlined/backend/KSConfiguration.kt
+++ b/src/main/kotlin/io/github/reactivecircus/kstreamlined/backend/KSConfiguration.kt
@@ -1,14 +1,24 @@
 package io.github.reactivecircus.kstreamlined.backend
 
+import com.netflix.graphql.dgs.webflux.autoconfiguration.DgsWebfluxConfigurationProperties
 import io.github.reactivecircus.kstreamlined.backend.client.ClientConfigs
 import io.github.reactivecircus.kstreamlined.backend.client.FeedClient
 import io.github.reactivecircus.kstreamlined.backend.client.RealFeedClient
-import io.ktor.client.engine.cio.CIO
+import io.ktor.client.engine.cio.*
+import org.springframework.aot.hint.annotation.RegisterReflectionForBinding
 import org.springframework.beans.factory.annotation.Value
 import org.springframework.context.annotation.Bean
 import org.springframework.context.annotation.Configuration
+import org.springframework.context.annotation.ImportRuntimeHints
 
 @Configuration
+@ImportRuntimeHints(KStreamlinedRuntimeHints::class)
+@RegisterReflectionForBinding(
+    DgsWebfluxConfigurationProperties::class,
+    DgsWebfluxConfigurationProperties.DgsWebsocketConfigurationProperties::class,
+    DgsWebfluxConfigurationProperties.DgsGraphiQLConfigurationProperties::class,
+    DgsWebfluxConfigurationProperties.DgsSchemaJsonConfigurationProperties::class,
+)
 class KSConfiguration {
 
     @Bean
diff --git a/src/main/kotlin/io/github/reactivecircus/kstreamlined/backend/KStreamlinedRuntimeHints.kt b/src/main/kotlin/io/github/reactivecircus/kstreamlined/backend/KStreamlinedRuntimeHints.kt
new file mode 100644
index 0000000..a9d13fe
--- /dev/null
+++ b/src/main/kotlin/io/github/reactivecircus/kstreamlined/backend/KStreamlinedRuntimeHints.kt
@@ -0,0 +1,24 @@
+package io.github.reactivecircus.kstreamlined.backend
+
+import org.springframework.aot.hint.ExecutableMode
+import org.springframework.aot.hint.RuntimeHints
+import org.springframework.aot.hint.RuntimeHintsRegistrar
+import org.springframework.aot.hint.TypeReference
+
+object KStreamlinedRuntimeHints : RuntimeHintsRegistrar {
+    override fun registerHints(hints: RuntimeHints, classLoader: ClassLoader?) {
+        hints.reflection()
+            .registerType(
+                TypeReference.of("com.github.benmanes.caffeine.cache.SSA")
+            ) { builder ->
+                builder.withConstructor(
+                    listOf(
+                        TypeReference.of("com.github.benmanes.caffeine.cache.Caffeine"),
+                        TypeReference.of("com.github.benmanes.caffeine.cache.AsyncCacheLoader"),
+                        TypeReference.of("boolean"),
+                    ),
+                    ExecutableMode.INVOKE,
+                )
+            }
+    }
+}
diff --git a/src/main/kotlin/io/github/reactivecircus/kstreamlined/backend/datafetcher/FeedEntryDataFetcher.kt b/src/main/kotlin/io/github/reactivecircus/kstreamlined/backend/datafetcher/FeedEntryDataFetcher.kt
index d2954e3..01a4229 100644
--- a/src/main/kotlin/io/github/reactivecircus/kstreamlined/backend/datafetcher/FeedEntryDataFetcher.kt
+++ b/src/main/kotlin/io/github/reactivecircus/kstreamlined/backend/datafetcher/FeedEntryDataFetcher.kt
@@ -33,8 +33,9 @@ import java.time.Duration
 @DgsComponent
 class FeedEntryDataFetcher(
     private val feedClient: FeedClient,
-    private val coroutineDispatcher: CoroutineDispatcher = Dispatchers.IO,
 ) {
+    private val coroutineDispatcher: CoroutineDispatcher = Dispatchers.IO
+
     private val kotlinBlogCacheContext = object : CacheContext<KotlinBlogItem> {
         override val cache: Cache<Unit, List<KotlinBlogItem>> = Caffeine
             .newBuilder()