feat(config): Add exporter customizers for declarative config (#6576)

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

@@ -36,6 +36,7 @@ class DeclarativeConfigContext {
   @Nullable private Resource resource = null;
   @Nullable private ConfigProvider configProvider;
   @Nullable private List<ComponentProvider> componentProviders = null;
+  @Nullable private DeclarativeConfigurationBuilder builder;
 
   // Visible for testing
   DeclarativeConfigContext(SpiHelper spiHelper) {
@@ -79,6 +80,14 @@ void setResource(Resource resource) {
     this.resource = resource;
   }
 
+  void setBuilder(DeclarativeConfigurationBuilder builder) {
+    this.builder = builder;
+  }
+
+  DeclarativeConfigurationBuilder getBuilder() {
+    return Objects.requireNonNull(builder, "builder has not been set");
+  }
+
   /**
    * Overload of {@link #setInternalTelemetry(Consumer, Consumer)} for components which do not
    * support setting {@link InternalTelemetryVersion} because they only support {@link

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

@@ -160,6 +160,7 @@ public static ExtendedOpenTelemetrySdk create(
   private static ExtendedOpenTelemetrySdk create(
       OpenTelemetryConfigurationModel configurationModel, DeclarativeConfigContext context) {
     DeclarativeConfigurationBuilder builder = new DeclarativeConfigurationBuilder();
+    context.setBuilder(builder);
 
     SpiHelper spiHelper = context.getSpiHelper();
     for (DeclarativeConfigurationCustomizerProvider provider :

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

@@ -5,20 +5,68 @@
 
 package io.opentelemetry.sdk.extension.incubator.fileconfig;
 
+import io.opentelemetry.api.incubator.config.DeclarativeConfigException;
+import io.opentelemetry.api.incubator.config.DeclarativeConfigProperties;
 import io.opentelemetry.sdk.extension.incubator.fileconfig.internal.model.OpenTelemetryConfigurationModel;
+import io.opentelemetry.sdk.logs.export.LogRecordExporter;
+import io.opentelemetry.sdk.metrics.export.MetricExporter;
+import io.opentelemetry.sdk.trace.export.SpanExporter;
+import java.io.Closeable;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.function.BiFunction;
 import java.util.function.Function;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 
 /** Builder for the declarative configuration. */
 public class DeclarativeConfigurationBuilder implements DeclarativeConfigurationCustomizer {
   private Function<OpenTelemetryConfigurationModel, OpenTelemetryConfigurationModel>
       modelCustomizer = Function.identity();
 
+  private final List<Customizer<SpanExporter>> spanExporterCustomizers = new ArrayList<>();
+  private final List<Customizer<MetricExporter>> metricExporterCustomizers = new ArrayList<>();
+  private final List<Customizer<LogRecordExporter>> logRecordExporterCustomizers =
+      new ArrayList<>();
+
   @Override
   public void addModelCustomizer(
       Function<OpenTelemetryConfigurationModel, OpenTelemetryConfigurationModel> customizer) {
     modelCustomizer = mergeCustomizer(modelCustomizer, customizer);
   }
 
+  @Override
+  public <T extends SpanExporter> void addSpanExporterCustomizer(
+      Class<T> exporterType, BiFunction<T, DeclarativeConfigProperties, T> customizer) {
+    spanExporterCustomizers.add(new Customizer<>(exporterType, customizer));
+  }
+
+  @Override
+  public <T extends MetricExporter> void addMetricExporterCustomizer(
+      Class<T> exporterType, BiFunction<T, DeclarativeConfigProperties, T> customizer) {
+    metricExporterCustomizers.add(new Customizer<>(exporterType, customizer));
+  }
+
+  @Override
+  public <T extends LogRecordExporter> void addLogRecordExporterCustomizer(
+      Class<T> exporterType, BiFunction<T, DeclarativeConfigProperties, T> customizer) {
+    logRecordExporterCustomizers.add(new Customizer<>(exporterType, customizer));
+  }
+
+  List<Customizer<SpanExporter>> getSpanExporterCustomizers() {
+    return Collections.unmodifiableList(spanExporterCustomizers);
+  }
+
+  List<Customizer<MetricExporter>> getMetricExporterCustomizers() {
+    return Collections.unmodifiableList(metricExporterCustomizers);
+  }
+
+  List<Customizer<LogRecordExporter>> getLogRecordExporterCustomizers() {
+    return Collections.unmodifiableList(logRecordExporterCustomizers);
+  }
+
   private static <I, O1, O2> Function<I, O2> mergeCustomizer(
       Function<? super I, ? extends O1> first, Function<? super O1, ? extends O2> second) {
     return (I configured) -> {
@@ -32,4 +80,37 @@ public OpenTelemetryConfigurationModel customizeModel(
       OpenTelemetryConfigurationModel configurationModel) {
     return modelCustomizer.apply(configurationModel);
   }
+
+  static class Customizer<T> {
+    private static final Logger logger = Logger.getLogger(Customizer.class.getName());
+
+    private final Class<? extends T> exporterType;
+    private final BiFunction<T, DeclarativeConfigProperties, T> customizer;
+
+    @SuppressWarnings("unchecked")
+    <E extends T> Customizer(
+        Class<E> exporterType, BiFunction<E, DeclarativeConfigProperties, E> customizer) {
+      this.exporterType = exporterType;
+      this.customizer = (BiFunction<T, DeclarativeConfigProperties, T>) customizer;
+    }
+
+    T maybeCustomize(T exporter, String name, DeclarativeConfigProperties properties) {
+      if (!exporterType.isInstance(exporter)) {
+        return exporter;
+      }
+      T customized = customizer.apply(exporter, properties);
+      if (customized == null) {
+        throw new DeclarativeConfigException(
+            "Customizer returned null for " + exporterType.getSimpleName() + ": " + name);
+      }
+      if (customized != exporter && exporter instanceof Closeable) {
+        try {
+          ((Closeable) exporter).close();
+        } catch (IOException e) {
+          logger.log(Level.WARNING, "Failed to close exporter after customization", e);
+        }
+      }
+      return customized;
+    }
+  }
 }

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

@@ -5,7 +5,12 @@
 
 package io.opentelemetry.sdk.extension.incubator.fileconfig;
 
+import io.opentelemetry.api.incubator.config.DeclarativeConfigProperties;
 import io.opentelemetry.sdk.extension.incubator.fileconfig.internal.model.OpenTelemetryConfigurationModel;
+import io.opentelemetry.sdk.logs.export.LogRecordExporter;
+import io.opentelemetry.sdk.metrics.export.MetricExporter;
+import io.opentelemetry.sdk.trace.export.SpanExporter;
+import java.util.function.BiFunction;
 import java.util.function.Function;
 
 /** A service provider interface (SPI) for customizing declarative configuration. */
@@ -18,4 +23,43 @@ public interface DeclarativeConfigurationCustomizer {
    */
   void addModelCustomizer(
       Function<OpenTelemetryConfigurationModel, OpenTelemetryConfigurationModel> customizer);
+
+  /**
+   * Add customizer for {@link SpanExporter} instances created from declarative configuration.
+   * Multiple customizers compose in registration order.
+   *
+   * @param exporterType the exporter type to customize
+   * @param customizer function receiving (exporter, properties) and returning customized exporter;
+   *     must not return null
+   * @param <T> the exporter type
+   */
+  <T extends SpanExporter> void addSpanExporterCustomizer(
+      Class<T> exporterType, BiFunction<T, DeclarativeConfigProperties, T> customizer);
+
+  /**
+   * Add customizer for {@link MetricExporter} instances created from declarative configuration.
+   * Multiple customizers compose in registration order.
+   *
+   * @param exporterType the exporter type to customize
+   * @param customizer function receiving (exporter, properties) and returning customized exporter;
+   *     must not return null
+   * @param <T> the exporter type
+   */
+  <T extends MetricExporter> void addMetricExporterCustomizer(
+      Class<T> exporterType, BiFunction<T, DeclarativeConfigProperties, T> customizer);
+
+  /**
+   * Add customizer for {@link LogRecordExporter} instances created from declarative configuration.
+   * Multiple customizers compose in registration order.
+   *
+   * <p>If the customizer wraps the exporter in a new {@link java.io.Closeable} instance, the
+   * customizer is responsible for resource cleanup.
+   *
+   * @param exporterType the exporter type to customize
+   * @param customizer function receiving (exporter, properties) and returning customized exporter;
+   *     must not return null
+   * @param <T> the exporter type
+   */
+  <T extends LogRecordExporter> void addLogRecordExporterCustomizer(
+      Class<T> exporterType, BiFunction<T, DeclarativeConfigProperties, T> customizer);
 }

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

@@ -21,6 +21,14 @@ static LogRecordExporterFactory getInstance() {
   public LogRecordExporter create(LogRecordExporterModel model, DeclarativeConfigContext context) {
     ConfigKeyValue logRecordExporterKeyValue =
         FileConfigUtil.validateSingleKeyValue(context, model, "log record exporter");
-    return context.loadComponent(LogRecordExporter.class, logRecordExporterKeyValue);
+    LogRecordExporter exporter =
+        context.loadComponent(LogRecordExporter.class, logRecordExporterKeyValue);
+    for (DeclarativeConfigurationBuilder.Customizer<LogRecordExporter> customizer :
+        context.getBuilder().getLogRecordExporterCustomizers()) {
+      exporter =
+          customizer.maybeCustomize(
+              exporter, logRecordExporterKeyValue.getKey(), logRecordExporterKeyValue.getValue());
+    }
+    return exporter;
   }
 }

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

@@ -21,6 +21,13 @@ static MetricExporterFactory getInstance() {
   public MetricExporter create(PushMetricExporterModel model, DeclarativeConfigContext context) {
     ConfigKeyValue metricExporterKeyValue =
         FileConfigUtil.validateSingleKeyValue(context, model, "metric exporter");
-    return context.loadComponent(MetricExporter.class, metricExporterKeyValue);
+    MetricExporter exporter = context.loadComponent(MetricExporter.class, metricExporterKeyValue);
+    for (DeclarativeConfigurationBuilder.Customizer<MetricExporter> customizer :
+        context.getBuilder().getMetricExporterCustomizers()) {
+      exporter =
+          customizer.maybeCustomize(
+              exporter, metricExporterKeyValue.getKey(), metricExporterKeyValue.getValue());
+    }
+    return exporter;
   }
 }

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

@@ -22,6 +22,13 @@ static SpanExporterFactory getInstance() {
   public SpanExporter create(SpanExporterModel model, DeclarativeConfigContext context) {
     ConfigKeyValue spanExporterKeyValue =
         FileConfigUtil.validateSingleKeyValue(context, model, "span exporter");
-    return context.loadComponent(SpanExporter.class, spanExporterKeyValue);
+    SpanExporter exporter = context.loadComponent(SpanExporter.class, spanExporterKeyValue);
+    for (DeclarativeConfigurationBuilder.Customizer<SpanExporter> customizer :
+        context.getBuilder().getSpanExporterCustomizers()) {
+      exporter =
+          customizer.maybeCustomize(
+              exporter, spanExporterKeyValue.getKey(), spanExporterKeyValue.getValue());
+    }
+    return exporter;
   }
 }

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

@@ -0,0 +1,116 @@
+/*
+ * 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 static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+
+import io.opentelemetry.api.incubator.config.DeclarativeConfigProperties;
+import io.opentelemetry.sdk.logs.export.LogRecordExporter;
+import io.opentelemetry.sdk.metrics.export.MetricExporter;
+import io.opentelemetry.sdk.trace.export.SpanExporter;
+import org.junit.jupiter.api.Test;
+
+class DeclarativeConfigurationBuilderTest {
+
+  @Test
+  void spanExporterCustomizer_Single() {
+    DeclarativeConfigurationBuilder builder = new DeclarativeConfigurationBuilder();
+
+    builder.addSpanExporterCustomizer(
+        SpanExporter.class, (exporter, properties) -> mock(SpanExporter.class));
+
+    assertThat(builder.getSpanExporterCustomizers()).hasSize(1);
+  }
+
+  @Test
+  void spanExporterCustomizer_Multiple_Compose() {
+    DeclarativeConfigurationBuilder builder = new DeclarativeConfigurationBuilder();
+
+    builder.addSpanExporterCustomizer(
+        SpanExporter.class, (exporter, properties) -> mock(SpanExporter.class));
+    builder.addSpanExporterCustomizer(
+        SpanExporter.class, (exporter, properties) -> mock(SpanExporter.class));
+
+    assertThat(builder.getSpanExporterCustomizers()).hasSize(2);
+  }
+
+  @Test
+  void metricExporterCustomizer_Single() {
+    DeclarativeConfigurationBuilder builder = new DeclarativeConfigurationBuilder();
+
+    builder.addMetricExporterCustomizer(
+        MetricExporter.class, (exporter, properties) -> mock(MetricExporter.class));
+
+    assertThat(builder.getMetricExporterCustomizers()).hasSize(1);
+  }
+
+  @Test
+  void metricExporterCustomizer_Multiple_Compose() {
+    DeclarativeConfigurationBuilder builder = new DeclarativeConfigurationBuilder();
+
+    builder.addMetricExporterCustomizer(
+        MetricExporter.class, (exporter, properties) -> mock(MetricExporter.class));
+    builder.addMetricExporterCustomizer(
+        MetricExporter.class, (exporter, properties) -> mock(MetricExporter.class));
+
+    assertThat(builder.getMetricExporterCustomizers()).hasSize(2);
+  }
+
+  @Test
+  void logRecordExporterCustomizer_Single() {
+    DeclarativeConfigurationBuilder builder = new DeclarativeConfigurationBuilder();
+
+    builder.addLogRecordExporterCustomizer(
+        LogRecordExporter.class, (exporter, properties) -> mock(LogRecordExporter.class));
+
+    assertThat(builder.getLogRecordExporterCustomizers()).hasSize(1);
+  }
+
+  @Test
+  void logRecordExporterCustomizer_Multiple_Compose() {
+    DeclarativeConfigurationBuilder builder = new DeclarativeConfigurationBuilder();
+
+    builder.addLogRecordExporterCustomizer(
+        LogRecordExporter.class, (exporter, properties) -> mock(LogRecordExporter.class));
+    builder.addLogRecordExporterCustomizer(
+        LogRecordExporter.class, (exporter, properties) -> mock(LogRecordExporter.class));
+
+    assertThat(builder.getLogRecordExporterCustomizers()).hasSize(2);
+  }
+
+  @Test
+  void customizer_ClosesOriginalWhenReplaced() throws Exception {
+    SpanExporter original = mock(SpanExporter.class);
+    SpanExporter replacement = mock(SpanExporter.class);
+    DeclarativeConfigProperties props = mock(DeclarativeConfigProperties.class);
+
+    DeclarativeConfigurationBuilder.Customizer<SpanExporter> customizer =
+        new DeclarativeConfigurationBuilder.Customizer<>(
+            SpanExporter.class, (exporter, properties) -> replacement);
+
+    SpanExporter result = customizer.maybeCustomize(original, "test", props);
+
+    assertThat(result).isSameAs(replacement);
+    verify(original).close();
+  }
+
+  @Test
+  void customizer_DoesNotCloseWhenSameInstance() throws Exception {
+    SpanExporter exporter = mock(SpanExporter.class);
+    DeclarativeConfigProperties props = mock(DeclarativeConfigProperties.class);
+
+    DeclarativeConfigurationBuilder.Customizer<SpanExporter> customizer =
+        new DeclarativeConfigurationBuilder.Customizer<>(SpanExporter.class, (e, properties) -> e);
+
+    SpanExporter result = customizer.maybeCustomize(exporter, "test", props);
+
+    assertThat(result).isSameAs(exporter);
+    verify(exporter, never()).close();
+  }
+}

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

@@ -114,7 +114,7 @@ void parseAndCreate_Exception_CleansUpPartials() {
     // exporter with OTLP exporter, following by invalid batch exporter which references invalid
     // exporter "foo".
     String yaml =
-        "file_format: \"1.0-rc.1\"\n"
+        "file_format: \"1.0-rc.3\"\n"
             + "logger_provider:\n"
             + "  processors:\n"
             + "    - batch:\n"
@@ -141,7 +141,7 @@ void parseAndCreate_Exception_CleansUpPartials() {
   @Test
   void parseAndCreate_EmptyComponentProviderConfig() {
     String yaml =
-        "file_format: \"1.0-rc.1\"\n"
+        "file_format: \"1.0-rc.3\"\n"
             + "logger_provider:\n"
             + "  processors:\n"
             + "    - test:\n"
@@ -159,7 +159,7 @@ void parseAndCreate_EmptyComponentProviderConfig() {
   @Test
   void create_ModelCustomizer() {
     OpenTelemetryConfigurationModel model = new OpenTelemetryConfigurationModel();
-    model.withFileFormat("1.0-rc.1");
+    model.withFileFormat("1.0-rc.3");
     model.withTracerProvider(
         new TracerProviderModel()
             .withProcessors(