add system properties bridge

Author: zeitlinger

instrumentation-api/build.gradle.kts

@@ -22,6 +22,7 @@ dependencies {
   testImplementation("io.opentelemetry.javaagent:opentelemetry-testing-common")
   testImplementation("io.opentelemetry:opentelemetry-sdk-testing")
   testImplementation("io.opentelemetry:opentelemetry-exporter-common")
+  testImplementation("io.opentelemetry:opentelemetry-sdk-extension-incubator")
   testImplementation("org.junit-pioneer:junit-pioneer")
 
   jmhImplementation(project(":instrumentation-api-incubator"))

instrumentation-api/src/main/java/io/opentelemetry/instrumentation/api/internal/ConfigPropertiesUtil.java

@@ -5,6 +5,8 @@
 
 package io.opentelemetry.instrumentation.api.internal;
 
+import static io.opentelemetry.api.incubator.config.DeclarativeConfigProperties.empty;
+
 import io.opentelemetry.api.OpenTelemetry;
 import io.opentelemetry.api.incubator.ExtendedOpenTelemetry;
 import io.opentelemetry.api.incubator.config.ConfigProvider;
@@ -15,8 +17,6 @@
 import java.util.stream.Collectors;
 import javax.annotation.Nullable;
 
-import static io.opentelemetry.api.incubator.config.DeclarativeConfigProperties.empty;
-
 /**
  * This class is internal and is hence not for public use. Its APIs are unstable and can change at
  * any time.
@@ -40,9 +40,12 @@ private static boolean isIncubator() {
   }
 
   /**
-   * @deprecated use {@link #getBoolean(OpenTelemetry, boolean, String...)} instead
+   * Returns the boolean value of the given property name from system properties and environment
+   * variables.
+   *
+   * <p>It's recommended to use {@link #getBoolean(OpenTelemetry, boolean, String...)} instead to
+   * support Declarative Config.
    */
-  @Deprecated
   public static boolean getBoolean(String propertyName, boolean defaultValue) {
     String strValue = getString(propertyName);
     return strValue == null ? defaultValue : Boolean.parseBoolean(strValue);
@@ -54,7 +57,6 @@ public static boolean getBoolean(String propertyName, boolean defaultValue) {
    */
   public static boolean getBoolean(
       OpenTelemetry openTelemetry, boolean defaultValue, String... propertyName) {
-
     DeclarativeConfigProperties node = getDeclarativeConfigNode(openTelemetry, propertyName);
     if (node != null) {
       return node.getBoolean(propertyName[propertyName.length - 1], defaultValue);
@@ -127,8 +129,9 @@ private static DeclarativeConfigProperties getDeclarativeConfigNode(
     return null;
   }
 
-  private static String toSystemProperty(String[] propertyName) {
-    return String.join(".", propertyName).replace('_', '-');
+  // Visible for testing
+  static String toSystemProperty(String[] propertyName) {
+    return "otel.instrumentation." + String.join(".", propertyName).replace('_', '-');
   }
 
   private ConfigPropertiesUtil() {}

instrumentation-api/src/test/java/io/opentelemetry/instrumentation/api/internal/ConfigPropertiesUtilTest.java

@@ -7,6 +7,12 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 
+import io.opentelemetry.sdk.extension.incubator.fileconfig.DeclarativeConfiguration;
+import io.opentelemetry.sdk.extension.incubator.fileconfig.DeclarativeConfigurationBuilder;
+import io.opentelemetry.sdk.extension.incubator.fileconfig.internal.model.ExperimentalLanguageSpecificInstrumentationModel;
+import io.opentelemetry.sdk.extension.incubator.fileconfig.internal.model.InstrumentationModel;
+import io.opentelemetry.sdk.extension.incubator.fileconfig.internal.model.OpenTelemetryConfigurationModel;
+import java.util.Collections;
 import org.junit.jupiter.api.Test;
 import org.junitpioneer.jupiter.SetEnvironmentVariable;
 import org.junitpioneer.jupiter.SetSystemProperty;
@@ -72,4 +78,31 @@ void getBoolean_environmentVariable() {
   void getBoolean_none() {
     assertThat(ConfigPropertiesUtil.getBoolean("test.property.boolean", false)).isFalse();
   }
+
+  @Test
+  void getBoolean_declarativeConfig() {
+    assertThat(
+            ConfigPropertiesUtil.getBoolean(
+                DeclarativeConfiguration.create(model(true)), false, "foo", "bar"))
+        .isTrue();
+  }
+
+  private static OpenTelemetryConfigurationModel model(Object value) {
+    return new DeclarativeConfigurationBuilder()
+        .customizeModel(
+            new OpenTelemetryConfigurationModel()
+                .withFileFormat("1.0-rc.1")
+                .withInstrumentationDevelopment(
+                    new InstrumentationModel()
+                        .withJava(
+                            new ExperimentalLanguageSpecificInstrumentationModel()
+                                .withAdditionalProperty(
+                                    "foo", Collections.singletonMap("bar", value)))));
+  }
+
+  @Test
+  void toSystemProperty() {
+    assertThat(ConfigPropertiesUtil.toSystemProperty(new String[] {"a_b", "c", "d"}))
+        .isEqualTo("otel.instrumentation.a-b.c.d");
+  }
 }