Ensure GlobalLoggerProvider is set once (#4804)

* Ensure GlobalLoggerProvider is set once

* Add GlobalLoggerProviderTest

* PR feedback

Author: jack-berg

api/logs/src/main/java/io/opentelemetry/api/logs/GlobalLoggerProvider.java

@@ -6,20 +6,29 @@
 package io.opentelemetry.api.logs;
 
 import io.opentelemetry.api.GlobalOpenTelemetry;
+import java.util.concurrent.atomic.AtomicReference;
+import javax.annotation.Nullable;
 
 /**
  * This class provides a temporary global accessor for {@link LoggerProvider} until the log API is
  * marked stable. It will eventually be merged into {@link GlobalOpenTelemetry}.
  */
+// We intentionally assign to be used for error reporting.
+@SuppressWarnings("StaticAssignmentOfThrowable")
 public final class GlobalLoggerProvider {
 
-  private static volatile LoggerProvider globalLoggerProvider = DefaultLoggerProvider.getInstance();
+  private static final AtomicReference<LoggerProvider> instance =
+      new AtomicReference<>(LoggerProvider.noop());
+
+  @Nullable private static volatile Throwable setInstanceCaller;
 
   private GlobalLoggerProvider() {}
 
   /** Returns the globally registered {@link LoggerProvider}. */
+  // instance cannot be set to null
+  @SuppressWarnings("NullAway")
   public static LoggerProvider get() {
-    return globalLoggerProvider;
+    return instance.get();
   }
 
   /**
@@ -28,7 +37,22 @@ public static LoggerProvider get() {
    * application initialization logic.
    */
   public static void set(LoggerProvider loggerProvider) {
-    globalLoggerProvider =
-        loggerProvider == null ? DefaultLoggerProvider.getInstance() : loggerProvider;
+    boolean changed = instance.compareAndSet(LoggerProvider.noop(), loggerProvider);
+    if (!changed && (loggerProvider != LoggerProvider.noop())) {
+      throw new IllegalStateException(
+          "GlobalLoggerProvider.set has already been called. GlobalLoggerProvider.set "
+              + "must be called only once before any calls to GlobalLoggerProvider.get. "
+              + "Previous invocation set to cause of this exception.",
+          setInstanceCaller);
+    }
+    setInstanceCaller = new Throwable();
+  }
+
+  /**
+   * Unsets the global {@link LoggerProvider}. This is only meant to be used from tests which need
+   * to reconfigure {@link LoggerProvider}.
+   */
+  public static void resetForTest() {
+    instance.set(LoggerProvider.noop());
   }
 }

api/logs/src/test/java/io/opentelemetry/api/logs/GlobalLoggerProviderTest.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.api.logs;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+class GlobalLoggerProviderTest {
+
+  @BeforeAll
+  static void beforeClass() {
+    GlobalLoggerProvider.resetForTest();
+  }
+
+  @AfterEach
+  void after() {
+    GlobalLoggerProvider.resetForTest();
+  }
+
+  @Test
+  void setAndGet() {
+    assertThat(GlobalLoggerProvider.get()).isEqualTo(LoggerProvider.noop());
+    LoggerProvider loggerProvider =
+        instrumentationScopeName -> LoggerProvider.noop().loggerBuilder(instrumentationScopeName);
+    GlobalLoggerProvider.set(loggerProvider);
+    assertThat(GlobalLoggerProvider.get()).isEqualTo(loggerProvider);
+  }
+
+  @Test
+  void setThenSet() {
+    GlobalLoggerProvider.set(
+        instrumentationScopeName -> LoggerProvider.noop().loggerBuilder(instrumentationScopeName));
+    assertThatThrownBy(
+            () ->
+                GlobalLoggerProvider.set(
+                    instrumentationScopeName ->
+                        LoggerProvider.noop().loggerBuilder(instrumentationScopeName)))
+        .isInstanceOf(IllegalStateException.class)
+        .hasMessageContaining("GlobalLoggerProvider.set has already been called")
+        .hasStackTraceContaining("setThenSet");
+  }
+}

sdk-extensions/autoconfigure/src/test/java/io/opentelemetry/sdk/autoconfigure/AutoConfiguredOpenTelemetrySdkTest.java

@@ -126,6 +126,7 @@ public SdkLoggerProviderBuilder apply(
   @BeforeEach
   void resetGlobal() {
     GlobalOpenTelemetry.resetForTest();
+    GlobalLoggerProvider.resetForTest();
     builder =
         AutoConfiguredOpenTelemetrySdk.builder()
             .setResultAsGlobal(false)

sdk-extensions/autoconfigure/src/testInitializeRegistersGlobal/java/io/opentelemetry/sdk/autoconfigure/AutoConfiguredOpenTelemetrySdkTest.java

@@ -8,6 +8,7 @@
 import static org.assertj.core.api.Assertions.assertThat;
 
 import io.opentelemetry.api.GlobalOpenTelemetry;
+import io.opentelemetry.api.logs.GlobalLoggerProvider;
 import io.opentelemetry.sdk.OpenTelemetrySdk;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -17,6 +18,7 @@ class AutoConfiguredOpenTelemetrySdkTest {
   @BeforeEach
   void setUp() {
     GlobalOpenTelemetry.resetForTest();
+    GlobalLoggerProvider.resetForTest();
   }
 
   @Test

sdk-extensions/autoconfigure/src/testOtlp/java/io/opentelemetry/sdk/autoconfigure/OtlpGrpcConfigTest.java

@@ -16,6 +16,7 @@
 import com.google.common.collect.Lists;
 import com.linecorp.armeria.testing.junit5.server.SelfSignedCertificateExtension;
 import io.opentelemetry.api.GlobalOpenTelemetry;
+import io.opentelemetry.api.logs.GlobalLoggerProvider;
 import io.opentelemetry.api.metrics.MeterProvider;
 import io.opentelemetry.sdk.OpenTelemetrySdk;
 import io.opentelemetry.sdk.autoconfigure.spi.ConfigProperties;
@@ -58,13 +59,15 @@ class OtlpGrpcConfigTest {
   @BeforeEach
   void setUp() {
     GlobalOpenTelemetry.resetForTest();
+    GlobalLoggerProvider.resetForTest();
   }
 
   @AfterEach
   public void tearDown() {
     server.reset();
     shutdownGlobalSdk();
     GlobalOpenTelemetry.resetForTest();
+    GlobalLoggerProvider.resetForTest();
   }
 
   @Test

sdk-extensions/autoconfigure/src/testOtlp/java/io/opentelemetry/sdk/autoconfigure/OtlpHttpConfigTest.java

@@ -16,6 +16,7 @@
 
 import com.google.common.collect.Lists;
 import io.opentelemetry.api.GlobalOpenTelemetry;
+import io.opentelemetry.api.logs.GlobalLoggerProvider;
 import io.opentelemetry.api.metrics.MeterProvider;
 import io.opentelemetry.sdk.autoconfigure.spi.ConfigProperties;
 import io.opentelemetry.sdk.autoconfigure.spi.ConfigurationException;
@@ -44,12 +45,14 @@ class OtlpHttpConfigTest {
   void setUp() {
     server.reset();
     GlobalOpenTelemetry.resetForTest();
+    GlobalLoggerProvider.resetForTest();
   }
 
   @AfterEach
   public void tearDown() {
     shutdownGlobalSdk();
     GlobalOpenTelemetry.resetForTest();
+    GlobalLoggerProvider.resetForTest();
   }
 
   @Test