Add declarative configuration support

Register the distro's resource detector via DeclarativeConfigurationCustomizerProvider
(model customizer) and ComponentProvider SPIs so it works in DC mode.

Express default instrumentation properties in DC notation as the source of truth,
translated to otel.instrumentation.* keys for auto-configuration.
ConfigPropertiesBackedConfigProvider bridges them to DC paths automatically.

Supersedes #1062.

Signed-off-by: Gregor Zeitlinger <gregor.zeitlinger@grafana.com>

Author: zeitlinger

custom/build.gradle

@@ -1,45 +1,47 @@
 plugins {
-  id "java"
-  id "org.owasp.dependencycheck" version "12.2.0"
+    id "java"
+    id "org.owasp.dependencycheck" version "12.2.0"
 }
 
 apply from: "$rootDir/gradle/checkstyle.gradle"
 
 dependencies {
-  compileOnly("io.opentelemetry:opentelemetry-sdk")
-  compileOnly("io.opentelemetry.semconv:opentelemetry-semconv")
-  compileOnly("io.opentelemetry:opentelemetry-sdk-extension-autoconfigure")
-  compileOnly("io.opentelemetry.javaagent:opentelemetry-javaagent-extension-api")
-  compileOnly("io.opentelemetry.javaagent:opentelemetry-javaagent-tooling")
-
-  testImplementation("io.opentelemetry.semconv:opentelemetry-semconv")
-  testImplementation("io.opentelemetry:opentelemetry-sdk-extension-autoconfigure-spi")
-  testImplementation("io.opentelemetry.javaagent:opentelemetry-testing-common")
-  testImplementation("io.opentelemetry.javaagent:opentelemetry-javaagent-extension-api")
+    compileOnly("io.opentelemetry:opentelemetry-sdk")
+    compileOnly("io.opentelemetry.semconv:opentelemetry-semconv")
+    compileOnly("io.opentelemetry:opentelemetry-sdk-extension-autoconfigure")
+    compileOnly("io.opentelemetry:opentelemetry-sdk-extension-incubator")
+    compileOnly("io.opentelemetry.javaagent:opentelemetry-javaagent-extension-api")
+    compileOnly("io.opentelemetry.javaagent:opentelemetry-javaagent-tooling")
+
+    testImplementation("io.opentelemetry.semconv:opentelemetry-semconv")
+    testImplementation("io.opentelemetry:opentelemetry-sdk-extension-autoconfigure-spi")
+    testImplementation("io.opentelemetry.javaagent:opentelemetry-testing-common")
+    testImplementation("io.opentelemetry.javaagent:opentelemetry-javaagent-extension-api")
+    testImplementation("io.opentelemetry:opentelemetry-sdk-extension-incubator")
 }
 
 dependencyCheck {
-  skipConfigurations = ["checkstyle", "annotationProcessor"]
-  suppressionFile = "buildscripts/dependency-check-suppressions.xml"
-  failBuildOnCVSS = 7.0f // fail on high or critical CVE
+    skipConfigurations = ["checkstyle", "annotationProcessor"]
+    suppressionFile = "buildscripts/dependency-check-suppressions.xml"
+    failBuildOnCVSS = 7.0f // fail on high or critical CVE
 }
 
 def updateGeneratedFile(file, newContent) {
-  if (System.getenv("CHECK_GENERATED_FILES") == "true") {
-    def oldContent = file.text
-    if (oldContent != newContent) {
-      throw new GradleException("File ${file} was modified in CI. Please update it locally and commit.")
+    if (System.getenv("CHECK_GENERATED_FILES") == "true") {
+        def oldContent = file.text
+        if (oldContent != newContent) {
+            throw new GradleException("File ${file} was modified in CI. Please update it locally and commit.")
+        }
+    } else {
+        project.mkdir(file.parent)
+        file.text = newContent
     }
-  } else {
-    project.mkdir(file.parent)
-    file.text = newContent
-  }
 }
 
 tasks.register('manageVersionClass') {
-  doLast {
-    updateGeneratedFile(new File("${projectDir}/src/main/java/com/grafana/extensions/resources/internal", "DistributionVersion.java"),
-      """/*
+    doLast {
+        updateGeneratedFile(new File("${projectDir}/src/main/java/com/grafana/extensions/resources/internal", "DistributionVersion.java"),
+                """/*
  * Copyright Grafana Labs
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -53,7 +55,7 @@ public class DistributionVersion {
   public static final String VERSION = "$version";
 }
 """)
-  }
+    }
 }
 
 compileJava.dependsOn(manageVersionClass)

custom/src/main/java/com/grafana/extensions/GrafanaAutoConfigCustomizerProvider.java

@@ -15,20 +15,32 @@
 
 public class GrafanaAutoConfigCustomizerProvider implements AutoConfigurationCustomizerProvider {
 
+  // Defaults in DC notation (source of truth).
+  // Keys are DC paths under instrumentation/development.java.
+  // ConfigPropertiesBackedConfigProvider bridges these to ConfigProperties automatically.
+  static final Map<String, String> DC_DEFAULTS = new HashMap<>();
+
+  static {
+    DC_DEFAULTS.put("micrometer.base_time_unit", "s");
+    DC_DEFAULTS.put("log4j_appender.experimental_log_attributes", "true");
+    DC_DEFAULTS.put("logback_appender.experimental_log_attributes", "true");
+  }
+
   @Override
   public void customize(AutoConfigurationCustomizer autoConfiguration) {
     autoConfiguration
-        .addPropertiesSupplier(GrafanaAutoConfigCustomizerProvider::getDefaultProperties)
+        .addPropertiesSupplier(GrafanaAutoConfigCustomizerProvider::getDefaultConfigProperties)
         .addPropertiesCustomizer(TestedInstrumentationsCustomizer::customizeProperties)
         .addMeterProviderCustomizer(MetricsCustomizer::configure)
         .addResourceCustomizer(ResourceCustomizer::truncate);
   }
 
-  private static Map<String, String> getDefaultProperties() {
+  /** Translate DC defaults to {@code otel.instrumentation.*} keys for auto-configuration. */
+  private static Map<String, String> getDefaultConfigProperties() {
     HashMap<String, String> map = new HashMap<>();
-    map.put("otel.instrumentation.micrometer.base-time-unit", "s");
-    map.put("otel.instrumentation.log4j-appender.experimental-log-attributes", "true");
-    map.put("otel.instrumentation.logback-appender.experimental-log-attributes", "true");
+    for (Map.Entry<String, String> entry : DC_DEFAULTS.entrySet()) {
+      map.put("otel.instrumentation." + entry.getKey().replace('_', '-'), entry.getValue());
+    }
     return map;
   }
 }

custom/src/main/java/com/grafana/extensions/GrafanaDeclarativeConfigurationCustomizerProvider.java

@@ -0,0 +1,23 @@
+/*
+ * Copyright Grafana Labs
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package com.grafana.extensions;
+
+import com.grafana.extensions.resources.internal.DistroComponentProvider;
+import io.opentelemetry.sdk.extension.incubator.fileconfig.DeclarativeConfigurationCustomizer;
+import io.opentelemetry.sdk.extension.incubator.fileconfig.DeclarativeConfigurationCustomizerProvider;
+
+public class GrafanaDeclarativeConfigurationCustomizerProvider
+    implements DeclarativeConfigurationCustomizerProvider {
+
+  @Override
+  public void customize(DeclarativeConfigurationCustomizer customizer) {
+    customizer.addModelCustomizer(
+        model -> {
+          DistroComponentProvider.addDistroResourceProvider(model);
+          return model;
+        });
+  }
+}

custom/src/main/java/com/grafana/extensions/resources/internal/DistroComponentProvider.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright Grafana Labs
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package com.grafana.extensions.resources.internal;
+
+import com.grafana.extensions.resources.DistributionResource;
+import io.opentelemetry.api.incubator.config.DeclarativeConfigProperties;
+import io.opentelemetry.sdk.autoconfigure.spi.internal.ComponentProvider;
+import io.opentelemetry.sdk.extension.incubator.fileconfig.internal.model.ExperimentalResourceDetectionModel;
+import io.opentelemetry.sdk.extension.incubator.fileconfig.internal.model.ExperimentalResourceDetectorModel;
+import io.opentelemetry.sdk.extension.incubator.fileconfig.internal.model.OpenTelemetryConfigurationModel;
+import io.opentelemetry.sdk.extension.incubator.fileconfig.internal.model.ResourceModel;
+import io.opentelemetry.sdk.resources.Resource;
+import java.util.Collections;
+import java.util.List;
+import java.util.Objects;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+@SuppressWarnings("rawtypes")
+public class DistroComponentProvider implements ComponentProvider {
+
+  static final String GRAFANA_JAVAAGENT_DISTRIBUTION = "grafana-javaagent-distribution";
+  private static final List<String> REQUIRED_DETECTORS =
+      Collections.singletonList(GRAFANA_JAVAAGENT_DISTRIBUTION);
+
+  public static void addDistroResourceProvider(OpenTelemetryConfigurationModel model) {
+    ResourceModel resource = model.getResource();
+    if (resource == null) {
+      resource = new ResourceModel();
+      model.withResource(resource);
+    }
+    ExperimentalResourceDetectionModel detectionModel = resource.getDetectionDevelopment();
+    if (detectionModel == null) {
+      detectionModel = new ExperimentalResourceDetectionModel();
+      resource.withDetectionDevelopment(detectionModel);
+    }
+    List<ExperimentalResourceDetectorModel> detectors =
+        Objects.requireNonNull(detectionModel.getDetectors());
+    Set<String> names =
+        detectors.stream()
+            .flatMap(detector -> detector.getAdditionalProperties().keySet().stream())
+            .collect(Collectors.toSet());
+
+    for (String name : REQUIRED_DETECTORS) {
+      if (!names.contains(name)) {
+        ExperimentalResourceDetectorModel detector = new ExperimentalResourceDetectorModel();
+        detector.getAdditionalProperties().put(name, null);
+        detectors.add(detector);
+      }
+    }
+  }
+
+  @Override
+  public Class<?> getType() {
+    return Resource.class;
+  }
+
+  @Override
+  public String getName() {
+    return GRAFANA_JAVAAGENT_DISTRIBUTION;
+  }
+
+  @Override
+  public Object create(DeclarativeConfigProperties config) {
+    return DistributionResource.get();
+  }
+}

custom/src/main/resources/META-INF/services/io.opentelemetry.sdk.autoconfigure.spi.internal.ComponentProvider

@@ -0,0 +1 @@
+com.grafana.extensions.resources.internal.DistroComponentProvider

custom/src/main/resources/META-INF/services/io.opentelemetry.sdk.extension.incubator.fileconfig.DeclarativeConfigurationCustomizerProvider

@@ -0,0 +1 @@
+com.grafana.extensions.GrafanaDeclarativeConfigurationCustomizerProvider