normalize system props before lookup to avoid ambiguity of "experimental-foo" and "experimental.foo" that both translate to "foo/development"

Author: zeitlinger

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

@@ -12,9 +12,11 @@
 import io.opentelemetry.api.incubator.ExtendedOpenTelemetry;
 import io.opentelemetry.api.incubator.config.ConfigProvider;
 import io.opentelemetry.api.incubator.config.DeclarativeConfigProperties;
+import io.opentelemetry.api.internal.ConfigUtil;
 import java.util.Arrays;
+import java.util.HashMap;
 import java.util.List;
-import java.util.Locale;
+import java.util.Map;
 import java.util.Optional;
 import java.util.stream.Collectors;
 import javax.annotation.Nullable;
@@ -27,6 +29,26 @@ public final class ConfigPropertiesUtil {
 
   private static final boolean supportsDeclarativeConfig = supportsDeclarativeConfig();
 
+  private static final Map<String, String> config = load();
+
+  public static Map<String, String> load() {
+    Map<String, String> config = new HashMap<>();
+    System.getenv()
+        .forEach(
+            (name, value) -> config.put(ConfigUtil.normalizeEnvironmentVariableKey(name), value));
+    ConfigUtil.safeSystemProperties()
+        .forEach(
+            (key, value) ->
+                config.put(ConfigUtil.normalizePropertyKey(key.toString()), value.toString()));
+    return config;
+  }
+
+  /** Resets the cached config for testing purposes. */
+  public static void resetForTest() {
+    config.clear();
+    config.putAll(load());
+  }
+
   private static boolean supportsDeclarativeConfig() {
     try {
       Class.forName("io.opentelemetry.api.incubator.ExtendedOpenTelemetry");
@@ -91,11 +113,7 @@ public static int getInt(String propertyName, int defaultValue) {
    */
   @Nullable
   public static String getString(String propertyName) {
-    String value = System.getProperty(propertyName);
-    if (value != null) {
-      return value;
-    }
-    return System.getenv(toEnvVarName(propertyName));
+    return config.get(ConfigUtil.normalizePropertyKey(propertyName));
   }
 
   /**
@@ -136,10 +154,6 @@ private static List<String> filterBlanksAndNulls(String[] values) {
         .collect(Collectors.toList());
   }
 
-  private static String toEnvVarName(String propertyName) {
-    return propertyName.toUpperCase(Locale.ROOT).replace('-', '_').replace('.', '_');
-  }
-
   private static String leaf(String[] propertyName) {
     return propertyName[propertyName.length - 1];
   }
@@ -174,7 +188,7 @@ public static String toSystemProperty(String[] propertyName) {
     for (int i = 0; i < propertyName.length; i++) {
       if (propertyName[i].endsWith("/development")) {
         propertyName[i] =
-            "experimental-" + propertyName[i].substring(0, propertyName[i].length() - 12);
+            "experimental." + propertyName[i].substring(0, propertyName[i].length() - 12);
       }
     }
     return "otel.instrumentation." + String.join(".", propertyName).replace('_', '-');

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

@@ -19,6 +19,7 @@
 import java.util.Collections;
 import java.util.List;
 import java.util.stream.Stream;
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
@@ -28,6 +29,11 @@
 
 class ConfigPropertiesUtilTest {
 
+  @BeforeEach
+  void setUp() {
+    ConfigPropertiesUtil.resetForTest();
+  }
+
   @SetEnvironmentVariable(key = "TEST_PROPERTY_STRING", value = "env")
   @SetSystemProperty(key = "test.property.string", value = "sys")
   @Test
@@ -176,7 +182,7 @@ void toSystemProperty() {
     assertThat(ConfigPropertiesUtil.toSystemProperty(new String[] {"a_b", "c", "d"}))
         .isEqualTo("otel.instrumentation.a-b.c.d");
     assertThat(ConfigPropertiesUtil.toSystemProperty(new String[] {"a_b/development", "c", "d"}))
-        .isEqualTo("otel.instrumentation.experimental-a-b.c.d");
+        .isEqualTo("otel.instrumentation.experimental.a-b.c.d");
   }
 
   @SetEnvironmentVariable(key = "OTEL_INSTRUMENTATION_TEST_PROPERTY_LIST", value = "a,b,c")