make getInstrumentationConfig non-null (#7954)

Author: zeitlinger

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

@@ -5,7 +5,6 @@
 
 package io.opentelemetry.api.incubator.config;
 
-import javax.annotation.Nullable;
 import javax.annotation.concurrent.ThreadSafe;
 
 /**
@@ -23,15 +22,14 @@ public interface ConfigProvider {
   /**
    * Returns the {@link DeclarativeConfigProperties} corresponding to <a
    * href="https://github.com/open-telemetry/opentelemetry-configuration/blob/main/schema/instrumentation.json">instrumentation
-   * config</a>, or {@code null} if unavailable.
+   * config</a>, or {@link DeclarativeConfigProperties#empty()} if unavailable.
    *
    * @return the instrumentation {@link DeclarativeConfigProperties}
    */
-  @Nullable
   DeclarativeConfigProperties getInstrumentationConfig();
 
   /** Returns a no-op {@link ConfigProvider}. */
   static ConfigProvider noop() {
-    return () -> null;
+    return DeclarativeConfigProperties::empty;
   }
 }

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

@@ -136,9 +136,6 @@ public static <T> T getOrNull(
       Function<DeclarativeConfigProperties, T> accessor,
       String... segments) {
     DeclarativeConfigProperties config = configProvider.getInstrumentationConfig();
-    if (config == null) {
-      return null;
-    }
     for (String segment : segments) {
       config = config.getStructured(segment);
       if (config == null) {

api/incubator/src/testConvertToModel/java/io/opentelemetry/api/incubator/InstrumentationConfigUtilTest.java

@@ -62,12 +62,12 @@ void toMap_RoundTrip() throws JsonProcessingException {
 
   @Test
   void getInstrumentationConfigModel_UnsetConfig() {
-    ConfigProvider configProvider = () -> null;
+    ConfigProvider configProvider = DeclarativeConfigProperties::empty;
 
     assertThat(
             InstrumentationConfigUtil.getInstrumentationConfigModel(
                 configProvider, "my_instrumentation_library", MAPPER, Model.class))
-        .isEqualTo(null);
+        .isNull();
   }
 
   @Test

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

@@ -20,7 +20,6 @@
 import io.opentelemetry.api.GlobalOpenTelemetry;
 import io.opentelemetry.api.incubator.ExtendedOpenTelemetry;
 import io.opentelemetry.api.incubator.config.ConfigProvider;
-import io.opentelemetry.api.incubator.config.DeclarativeConfigProperties;
 import io.opentelemetry.api.incubator.config.InstrumentationConfigUtil;
 import io.opentelemetry.common.ComponentLoader;
 import io.opentelemetry.exporter.logging.LoggingSpanExporter;
@@ -40,7 +39,6 @@
 import java.nio.file.Path;
 import java.util.Arrays;
 import java.util.Collections;
-import java.util.Optional;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.RegisterExtension;
@@ -160,12 +158,10 @@ void configFile_setComponentLoader() {
     cleanup.addCloseable(autoConfiguredOpenTelemetrySdk.getOpenTelemetrySdk());
 
     assertThat(
-            Optional.ofNullable(
-                    ((ExtendedOpenTelemetry) autoConfiguredOpenTelemetrySdk.getOpenTelemetrySdk())
-                        .getConfigProvider()
-                        .getInstrumentationConfig())
-                .map(DeclarativeConfigProperties::getComponentLoader)
-                .orElse(null))
+            ((ExtendedOpenTelemetry) autoConfiguredOpenTelemetrySdk.getOpenTelemetrySdk())
+                .getConfigProvider()
+                .getInstrumentationConfig()
+                .getComponentLoader())
         .isSameAs(componentLoader);
   }
 
@@ -221,9 +217,6 @@ void configFile_ConfigProvider() {
 
     ConfigProvider globalConfigProvider =
         ((ExtendedOpenTelemetry) GlobalOpenTelemetry.get()).getConfigProvider();
-    DeclarativeConfigProperties instrumentationConfig =
-        globalConfigProvider.getInstrumentationConfig();
-    assertThat(instrumentationConfig).isNotNull();
 
     // Extract instrumentation config from ConfigProvider
     assertThat(InstrumentationConfigUtil.httpClientRequestCapturedHeaders(globalConfigProvider))

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

@@ -11,7 +11,6 @@
 import io.opentelemetry.sdk.OpenTelemetrySdk;
 import io.opentelemetry.sdk.extension.incubator.fileconfig.SdkConfigProvider;
 import java.io.Closeable;
-import javax.annotation.Nullable;
 import javax.annotation.concurrent.ThreadSafe;
 
 /** A new interface for creating OpenTelemetrySdk that supports getting {@link ConfigProvider}. */
@@ -74,7 +73,6 @@ private ObfuscatedConfigProvider(SdkConfigProvider delegate) {
     }
 
     @Override
-    @Nullable
     public DeclarativeConfigProperties getInstrumentationConfig() {
       return delegate.getInstrumentationConfig();
     }

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

@@ -5,22 +5,24 @@
 
 package io.opentelemetry.sdk.extension.incubator.fileconfig;
 
+import static io.opentelemetry.api.incubator.config.DeclarativeConfigProperties.empty;
+
 import io.opentelemetry.api.incubator.config.ConfigProvider;
 import io.opentelemetry.api.incubator.config.DeclarativeConfigProperties;
 import io.opentelemetry.common.ComponentLoader;
 import io.opentelemetry.sdk.extension.incubator.fileconfig.internal.model.OpenTelemetryConfigurationModel;
-import javax.annotation.Nullable;
 
 /** SDK implementation of {@link ConfigProvider}. */
 public final class SdkConfigProvider implements ConfigProvider {
 
-  @Nullable private final DeclarativeConfigProperties instrumentationConfig;
+  private final DeclarativeConfigProperties instrumentationConfig;
 
   private SdkConfigProvider(
       OpenTelemetryConfigurationModel model, ComponentLoader componentLoader) {
     DeclarativeConfigProperties configProperties =
         DeclarativeConfiguration.toConfigProperties(model, componentLoader);
-    this.instrumentationConfig = configProperties.getStructured("instrumentation/development");
+    this.instrumentationConfig =
+        configProperties.getStructured("instrumentation/development", empty());
   }
 
   /**
@@ -45,7 +47,6 @@ public static SdkConfigProvider create(
     return new SdkConfigProvider(model, componentLoader);
   }
 
-  @Nullable
   @Override
   public DeclarativeConfigProperties getInstrumentationConfig() {
     return instrumentationConfig;