add method to retrieve instrumentation configuration by name

api/incubator/src/main/java/io/opentelemetry/api/incubator/ExtendedOpenTelemetry.java

@@ -7,11 +7,49 @@
 
 import io.opentelemetry.api.OpenTelemetry;
 import io.opentelemetry.api.incubator.config.ConfigProvider;
+import io.opentelemetry.api.incubator.config.DeclarativeConfigProperties;
 
 /** Extension to {@link OpenTelemetry} with experimental APIs. */
 public interface ExtendedOpenTelemetry extends OpenTelemetry {
   /** Returns the {@link ConfigProvider} for this {@link OpenTelemetry}. */
   default ConfigProvider getConfigProvider() {
     return ConfigProvider.noop();
   }
+
+  /**
+   * Returns the {@link DeclarativeConfigProperties} for a specific instrumentation by name. If no
+   * configuration is available for the given name, an empty {@link DeclarativeConfigProperties} is
+   * returned.
+   *
+   * <p>For example, {@code getInstrumentationConfig("foo")} returns the node:
+   *
+   * <pre>{@code
+   * instrumentation/development:
+   *   java:
+   *     foo:
+   * }</pre>
+   *
+   * @param name the name of the instrumentation
+   * @return the {@link DeclarativeConfigProperties} for the given instrumentation name
+   */
+  default DeclarativeConfigProperties getInstrumentationConfig(String name) {
+    return getConfigProvider().getInstrumentationConfig(name);
+  }
+
+  /**
+   * Returns the {@link DeclarativeConfigProperties} for general instrumentation configuration.
+   *
+   * <pre>{@code
+   * instrumentation/development:
+   *   general:
+   * }</pre>
+   *
+   * <p>If the general configuration is not available, an empty {@link DeclarativeConfigProperties}
+   * is returned.
+   *
+   * @return the {@link DeclarativeConfigProperties} for the general instrumentation configuration
+   */
+  default DeclarativeConfigProperties getGeneralInstrumentationConfig() {
+    return getConfigProvider().getGeneralInstrumentationConfig();
+  }
 }

api/incubator/src/main/java/io/opentelemetry/api/incubator/config/ConfigProvider.java

@@ -28,6 +28,43 @@ public interface ConfigProvider {
    */
   DeclarativeConfigProperties getInstrumentationConfig();
 
+  /**
+   * Returns the {@link DeclarativeConfigProperties} for a specific instrumentation by name. If no
+   * configuration is available for the given name, an empty {@link DeclarativeConfigProperties} is
+   * returned.
+   *
+   * <p>For example, {@code getInstrumentationConfig("foo")} returns the node:
+   *
+   * <pre>{@code
+   * instrumentation/development:
+   *   java:
+   *     foo:
+   * }</pre>
+   *
+   * @param name the name of the instrumentation
+   * @return the {@link DeclarativeConfigProperties} for the given instrumentation name
+   */
+  default DeclarativeConfigProperties getInstrumentationConfig(String name) {
+    return getInstrumentationConfig().get("java").get(name);
+  }
+
+  /**
+   * Returns the {@link DeclarativeConfigProperties} for general instrumentation configuration.
+   *
+   * <pre>{@code
+   * instrumentation/development:
+   *   general:
+   * }</pre>
+   *
+   * <p>If the general configuration is not available, an empty {@link DeclarativeConfigProperties}
+   * is returned.
+   *
+   * @return the {@link DeclarativeConfigProperties} for the general instrumentation configuration
+   */
+  default DeclarativeConfigProperties getGeneralInstrumentationConfig() {
+    return getInstrumentationConfig().get("general");
+  }
+
   /** Returns a no-op {@link ConfigProvider}. */
   static ConfigProvider noop() {
     return DeclarativeConfigProperties::empty;

api/incubator/src/test/java/io/opentelemetry/api/incubator/ConfigProviderTest.java

@@ -17,4 +17,12 @@ void noopEquality() {
     ConfigProvider noop = ConfigProvider.noop();
     assertThat(ConfigProvider.noop()).isSameAs(noop);
   }
+
+  @Test
+  void instrumentationConfigFallback() {
+    ConfigProvider configProvider = ConfigProvider.noop();
+    assertThat(configProvider.getInstrumentationConfig()).isNotNull();
+    assertThat(configProvider.getInstrumentationConfig("servlet")).isNotNull();
+    assertThat(configProvider.getGeneralInstrumentationConfig()).isNotNull();
+  }
 }

api/incubator/src/test/java/io/opentelemetry/api/incubator/ExtendedOpenTelemetryTest.java

@@ -6,9 +6,12 @@
 package io.opentelemetry.api.incubator;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.when;
 
 import io.opentelemetry.api.GlobalOpenTelemetry;
 import io.opentelemetry.api.OpenTelemetry;
+import io.opentelemetry.api.incubator.config.ConfigProvider;
 import io.opentelemetry.api.incubator.logs.ExtendedDefaultLoggerProvider;
 import io.opentelemetry.api.incubator.logs.ExtendedLogger;
 import io.opentelemetry.api.incubator.metrics.ExtendedDefaultMeterProvider;
@@ -22,8 +25,12 @@
 import io.opentelemetry.context.propagation.ContextPropagators;
 import io.opentelemetry.sdk.OpenTelemetrySdk;
 import io.opentelemetry.sdk.extension.incubator.ExtendedOpenTelemetrySdk;
+import io.opentelemetry.sdk.extension.incubator.fileconfig.DeclarativeConfiguration;
 import io.opentelemetry.sdk.extension.incubator.fileconfig.SdkConfigProvider;
 import io.opentelemetry.sdk.extension.incubator.fileconfig.internal.model.OpenTelemetryConfigurationModel;
+import java.io.ByteArrayInputStream;
+import java.nio.charset.StandardCharsets;
+import java.util.Arrays;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
@@ -70,4 +77,50 @@ private static void assertIsExtended(OpenTelemetry openTelemetry) {
     assertThat(openTelemetry.getLogsBridge().get("test")).isInstanceOf(ExtendedLogger.class);
     assertThat(openTelemetry.getTracer("test")).isInstanceOf(ExtendedTracer.class);
   }
+
+  @Test
+  void instrumentationConfig() {
+    String configYaml =
+        "instrumentation/development:\n"
+            + "  general:\n"
+            + "    http:\n"
+            + "      client:\n"
+            + "        request_captured_headers:\n"
+            + "          - client-request-header1\n"
+            + "          - client-request-header2\n"
+            + "  java:\n"
+            + "    example:\n"
+            + "      property: \"value\"";
+
+    OpenTelemetryConfigurationModel configuration =
+        DeclarativeConfiguration.parse(
+            new ByteArrayInputStream(configYaml.getBytes(StandardCharsets.UTF_8)));
+    SdkConfigProvider configProvider = SdkConfigProvider.create(configuration);
+    ExtendedOpenTelemetry openTelemetry =
+        ExtendedOpenTelemetrySdk.create(OpenTelemetrySdk.builder().build(), configProvider);
+
+    // shortcuts to get specific instrumentation config
+    assertThat(openTelemetry.getInstrumentationConfig("example").getString("property"))
+        .isEqualTo("value");
+    assertThat(
+            openTelemetry
+                .getGeneralInstrumentationConfig()
+                .get("http")
+                .get("client")
+                .getScalarList("request_captured_headers", String.class))
+        .isEqualTo(Arrays.asList("client-request-header1", "client-request-header2"));
+  }
+
+  @Test
+  void instrumentationConfigFallback() {
+    ConfigProvider configProvider = ConfigProvider.noop();
+    // cannot create ExtendedOpenTelemetry with noop ConfigProvider right now,
+    // but will be possible once stable API is available
+    ExtendedOpenTelemetry openTelemetry = spy(ExtendedOpenTelemetry.class);
+    when(openTelemetry.getConfigProvider()).thenReturn(configProvider);
+
+    assertThat(configProvider.getInstrumentationConfig()).isNotNull();
+    assertThat(openTelemetry.getInstrumentationConfig("servlet")).isNotNull();
+    assertThat(openTelemetry.getGeneralInstrumentationConfig()).isNotNull();
+  }
 }

sdk-extensions/autoconfigure/src/testIncubating/java/io/opentelemetry/sdk/autoconfigure/DeclarativeConfigurationTest.java

@@ -224,5 +224,16 @@ void configFile_ConfigProvider() {
     assertThat(InstrumentationConfigUtil.javaInstrumentationConfig(globalConfigProvider, "example"))
         .isNotNull()
         .satisfies(exampleConfig -> assertThat(exampleConfig.getString("key")).isEqualTo("value"));
+
+    // shortcuts to get specific instrumentation config
+    assertThat(globalConfigProvider.getInstrumentationConfig("example").getString("key"))
+        .isEqualTo("value");
+    assertThat(
+            globalConfigProvider
+                .getGeneralInstrumentationConfig()
+                .get("http")
+                .get("client")
+                .getScalarList("request_captured_headers", String.class))
+        .isEqualTo(Arrays.asList("Content-Type", "Accept"));
   }
 }