add runtime hints for graal VM (#7866)

Author: zeitlinger

integration-tests/graal-incubating/build.gradle.kts

@@ -24,6 +24,7 @@ dependencies {
   implementation(project(":sdk:testing"))
   implementation(project(":exporters:otlp:all"))
   implementation(project(":api:incubator"))
+  implementation(project(":sdk-extensions:incubator"))
 }
 
 // org.graalvm.buildtools.native plugin requires java 17+ as of version 0.11.0

integration-tests/graal-incubating/src/test/java/io/opentelemetry/integrationtests/graal/IncubatingApiTests.java

@@ -23,6 +23,7 @@
 import io.opentelemetry.api.metrics.Meter;
 import io.opentelemetry.api.metrics.MeterProvider;
 import io.opentelemetry.api.trace.TracerProvider;
+import io.opentelemetry.sdk.extension.incubator.fileconfig.DeclarativeConfiguration;
 import io.opentelemetry.sdk.logs.SdkLoggerProvider;
 import io.opentelemetry.sdk.logs.export.SimpleLogRecordProcessor;
 import io.opentelemetry.sdk.metrics.SdkMeterProvider;
@@ -31,6 +32,8 @@
 import io.opentelemetry.sdk.testing.exporter.InMemorySpanExporter;
 import io.opentelemetry.sdk.trace.SdkTracerProvider;
 import io.opentelemetry.sdk.trace.export.SimpleSpanProcessor;
+import java.io.ByteArrayInputStream;
+import java.nio.charset.StandardCharsets;
 import org.junit.jupiter.api.Test;
 
 class IncubatingApiTests {
@@ -100,4 +103,28 @@ void incubatingMetricSdk() {
         (ExtendedLongGauge) meter.gaugeBuilder("longGauge").ofLongs().build();
     longGauge.isEnabled();
   }
+
+  @Test
+  void parseDeclarativeConfiguration() {
+    // make sure to test enums too: "instrument_type: histogram"
+    String string =
+        """
+      file_format: "1.0-rc.1"
+      tracer_provider:
+        processors:
+          - batch:
+              exporter:
+                console: {}
+      meter_provider:
+        views:
+          - selector:
+              instrument_type: histogram
+            stream:
+              aggregation:
+                drop: {}
+      """;
+    // should not throw
+    DeclarativeConfiguration.parse(
+        new ByteArrayInputStream(string.getBytes(StandardCharsets.UTF_8)));
+  }
 }

sdk-extensions/incubator/build.gradle.kts

@@ -145,8 +145,65 @@ val deleteJs2pTmp by tasks.registering(Delete::class) {
   delete("$buildDirectory/generated/sources/js2p-tmp/")
 }
 
+val buildGraalVmReflectionJson = tasks.register("buildGraalVmReflectionJson") {
+  val targetFile = File(
+    buildDirectory,
+    "resources/main/META-INF/native-image/io.opentelemetry/io.opentelemetry.sdk.extension.incubator/reflect-config.json"
+  )
+
+  onlyIf { !targetFile.exists() }
+
+  dependsOn("compileJava")
+
+  doLast {
+    println("Generating GraalVM reflection config at: ${targetFile.absolutePath}")
+    val sourcePackage =
+      "io.opentelemetry.sdk.extension.incubator.fileconfig.internal.model"
+    val sourcePackagePath = sourcePackage.replace(".", "/")
+
+    val classesDir =
+      File(
+        buildDirectory,
+        "classes/java/main/$sourcePackagePath"
+      )
+
+    val classes = mutableListOf<String>()
+    fileTree(classesDir).forEach {
+      val path = it.path
+
+      val className = path
+        .substringAfter(sourcePackagePath)
+        .removePrefix("/")
+        .removeSuffix(".class")
+        .replace("/", ".")
+      classes.add("$sourcePackage.$className")
+    }
+    classes.sort()
+
+    targetFile.parentFile.mkdirs()
+    targetFile.bufferedWriter().use { writer ->
+      writer.write("[\n")
+      classes.forEachIndexed { index, className ->
+        writer.write("  {\n")
+        writer.write("    \"name\": \"$className\",\n")
+        writer.write("    \"allDeclaredMethods\": true,\n")
+        writer.write("    \"allDeclaredFields\": true,\n")
+        writer.write("    \"allDeclaredConstructors\": true\n")
+        writer.write("  }")
+        if (index < classes.size - 1) {
+          writer.write(",\n")
+        } else {
+          writer.write("\n")
+        }
+      }
+      writer.write("]\n")
+    }
+  }
+}
+
 tasks.getByName("compileJava").dependsOn(deleteJs2pTmp)
-tasks.getByName("sourcesJar").dependsOn(deleteJs2pTmp)
+tasks.getByName("sourcesJar").dependsOn(deleteJs2pTmp, buildGraalVmReflectionJson)
+tasks.getByName("jar").dependsOn(deleteJs2pTmp, buildGraalVmReflectionJson)
 
 // Exclude jsonschema2pojo generated sources from checkstyle
 tasks.named<Checkstyle>("checkstyleMain") {