Initialize file configuration

buildSrc/src/main/kotlin/otel.java-conventions.gradle.kts

@@ -1,4 +1,5 @@
 import io.opentelemetry.gradle.OtelJavaExtension
+import org.gradle.api.plugins.quality.internal.CheckstyleAction
 import org.gradle.api.tasks.testing.logging.TestExceptionFormat
 
 plugins {

sdk-extensions/incubator/build.gradle.kts

@@ -1,9 +1,14 @@
+import de.undercouch.gradle.tasks.download.Download
+
 plugins {
   id("otel.java-conventions")
   id("otel.publish-conventions")
 
   id("otel.jmh-conventions")
   id("otel.animalsniffer-conventions")
+
+  id("de.undercouch.download")
+  id("org.jsonschema2pojo")
 }
 
 // SDK modules that are still being developed.
@@ -22,12 +27,63 @@ dependencies {
   implementation(project(":sdk-extensions:autoconfigure-spi"))
   implementation("org.snakeyaml:snakeyaml-engine")
 
-  // io.opentelemetry.sdk.extension.trace.zpages
+  // io.opentelemetry.sdk.extension.incubator.trace.zpages
   implementation(project(":semconv"))
   compileOnly("com.sun.net.httpserver:http")
 
+  // io.opentelemetry.sdk.extension.incubator.fileconfig
+  implementation("com.fasterxml.jackson.core:jackson-databind")
+  implementation("com.fasterxml.jackson.dataformat:jackson-dataformat-yaml")
+
   testImplementation(project(":sdk:testing"))
   testImplementation(project(":sdk-extensions:autoconfigure"))
 
   testImplementation("com.google.guava:guava-testlib")
 }
+
+val configurationRef = "74607f261e1f9a2ef356b7f87e394b6e9dd90285"
+val configurationRepoZip = "https://github.com/open-telemetry/opentelemetry-configuration/archive/$configurationRef.zip"
+
+val downloadConfigurationSchema by tasks.registering(Download::class) {
+  src(configurationRepoZip)
+  dest("$buildDir/configuration/opentelemetry-configuration.zip")
+  overwrite(false)
+}
+
+val downloadAndUnzipConfigurationSchema by tasks.registering(Copy::class) {
+  dependsOn("downloadConfigurationSchema")
+  from(zipTree(downloadConfigurationSchema.get().dest))
+  eachFile(closureOf<FileCopyDetails> {
+    // Remove the top level folder "/opentelemetry-configuration-$configurationRef"
+    val pathParts = path.split("/")
+    path = pathParts.subList(1, pathParts.size).joinToString("/")
+  })
+  into("$buildDir/configuration/")
+}
+
+jsonSchema2Pojo {
+  sourceFiles = setOf(file("$buildDir/configuration/schema"))
+  targetDirectory = file("$buildDir/generated/sources/js2p/java/main")
+  targetPackage = "io.opentelemetry.sdk.extension.incubator.fileconfig.internal.model"
+  includeSetters = false
+  removeOldOutput = true
+}
+
+tasks.getByName("generateJsonSchema2Pojo").dependsOn(downloadAndUnzipConfigurationSchema)
+tasks.getByName("sourcesJar").dependsOn("generateJsonSchema2Pojo")
+
+// Exclude jsonschema2pojo generated sources from checkstyle
+tasks.named<Checkstyle>("checkstyleMain") {
+  exclude("**/fileconfig/internal/model/**")
+}
+
+tasks {
+  withType<Test>().configureEach {
+    environment(
+      mapOf(
+        // Expose the kitchen sink example file to tests
+        "CONFIG_EXAMPLE_FILE" to "$buildDir/configuration/kitchen-sink-example.yaml"
+      )
+    )
+  }
+}

sdk-extensions/incubator/src/main/java/io/opentelemetry/sdk/extension/incubator/fileconfig/ConfigurationReader.java

@@ -0,0 +1,28 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.sdk.extension.incubator.fileconfig;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.dataformat.yaml.YAMLFactory;
+import io.opentelemetry.sdk.extension.incubator.fileconfig.internal.model.OpentelemetryConfiguration;
+import java.io.IOException;
+import java.io.InputStream;
+
+class ConfigurationReader {
+
+  private static final ObjectMapper MAPPER = new ObjectMapper(new YAMLFactory());
+
+  private ConfigurationReader() {}
+
+  /**
+   * Parse the {@code configuration} YAML and return the {@link OpentelemetryConfiguration}.
+   *
+   * @throws IOException if unable to parse
+   */
+  static OpentelemetryConfiguration parse(InputStream configuration) throws IOException {
+    return MAPPER.readValue(configuration, OpentelemetryConfiguration.class);
+  }
+}

sdk-extensions/incubator/src/test/java/io/opentelemetry/sdk/extension/incubator/fileconfig/ConfigurationReaderTest.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.sdk.extension.incubator.fileconfig;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import io.opentelemetry.sdk.extension.incubator.fileconfig.internal.model.OpentelemetryConfiguration;
+import java.io.FileInputStream;
+import java.io.IOException;
+import org.junit.jupiter.api.Test;
+
+class ConfigurationReaderTest {
+
+  @Test
+  void read_ExampleFile() throws IOException {
+    try (FileInputStream configExampleFile =
+        new FileInputStream(System.getenv("CONFIG_EXAMPLE_FILE"))) {
+      OpentelemetryConfiguration configuration = ConfigurationReader.parse(configExampleFile);
+
+      assertThat(configuration.getFileFormat()).isEqualTo("0.1");
+    }
+  }
+}

settings.gradle.kts

@@ -3,6 +3,8 @@ pluginManagement {
     id("com.github.ben-manes.versions") version "0.46.0"
     id("com.github.johnrengelman.shadow") version "8.1.1"
     id("com.gradle.enterprise") version "3.13"
+    id("de.undercouch.download") version "5.4.0"
+    id("org.jsonschema2pojo") version "1.2.1"
     id("io.github.gradle-nexus.publish-plugin") version "1.3.0"
     id("org.graalvm.buildtools.native") version "0.9.21"
   }