Include context metadata for Log4j2 and documentation update.

RELNOTES=Include context metadata for Log4j2. PiperOrigin-RevId: 379286898
google · Jun 14, 2021 · 8846b42 · 8846b42
1 parent 6fcdb0e
commit 8846b42
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Showing 3 changed files with 22 additions and 3 deletions.
diff --git a/log4j2/src/main/java/com/google/common/flogger/backend/log4j2/Log4j2BackendFactory.java b/log4j2/src/main/java/com/google/common/flogger/backend/log4j2/Log4j2BackendFactory.java
@@ -31,6 +31,11 @@
  *   <li>{@code flogger.backend_factory=
  *       com.google.common.flogger.backend.log4j2.Log4j2BackendFactory#getInstance}
  * </ul>
+ *
+ * <p>Note: Any changes in this code should, as far as possible, be reflected in the equivalently
+ * named log4j implementation. If the behaviour of this class starts to deviate from that of the
+ * log4j backend in any significant way, this difference should be called out clearly in the
+ * documentation.
  */
 public final class Log4j2BackendFactory extends BackendFactory {
   private static final Log4j2BackendFactory INSTANCE = new Log4j2BackendFactory();

diff --git a/log4j2/src/main/java/com/google/common/flogger/backend/log4j2/Log4j2LogEventUtil.java b/log4j2/src/main/java/com/google/common/flogger/backend/log4j2/Log4j2LogEventUtil.java
@@ -26,6 +26,7 @@
 import com.google.common.flogger.backend.MessageUtils;
 import com.google.common.flogger.backend.Metadata;
 import com.google.common.flogger.backend.MetadataProcessor;
+import com.google.common.flogger.backend.Platform;
 import com.google.common.flogger.backend.SimpleMessageFormatter;
 import java.util.Collections;
 import java.util.Map;
@@ -37,14 +38,20 @@
 import org.apache.logging.log4j.core.util.Throwables;
 import org.apache.logging.log4j.message.SimpleMessage;
 
-/** Helper to format LogData */
+/** Helper to format LogData.
+ *
+ * <p>Note: Any changes in this code should, as far as possible, be reflected in the equivalently
+ * named log4j implementation. If the behaviour of this class starts to deviate from that of the
+ * log4j backend in any significant way, this difference should be called out clearly in the
+ * documentation.
+ */
 final class Log4j2LogEventUtil {
 
   private Log4j2LogEventUtil() {}
 
   static LogEvent toLog4jLogEvent(String loggerName, LogData logData) {
     MetadataProcessor metadata =
-        MetadataProcessor.forScopeAndLogSite(Metadata.empty(), logData.getMetadata());
+        MetadataProcessor.forScopeAndLogSite(Platform.getInjectedMetadata(), logData.getMetadata());
     String message = SimpleMessageFormatter.getDefaultFormatter().format(logData, metadata);
     Throwable thrown = metadata.getSingleValue(LogContext.Key.LOG_CAUSE);
     return toLog4jLogEvent(

diff --git a/log4j2/src/main/java/com/google/common/flogger/backend/log4j2/Log4j2LoggerBackend.java b/log4j2/src/main/java/com/google/common/flogger/backend/log4j2/Log4j2LoggerBackend.java
@@ -23,7 +23,14 @@
 import com.google.common.flogger.backend.LoggerBackend;
 import org.apache.logging.log4j.core.Logger;
 
-/** A logging backend that uses log4j2 to output log statements. */
+/**
+ * A logging backend that uses log4j2 to output log statements.
+ *
+ * <p>Note: Any changes in this code should, as far as possible, be reflected in the equivalently
+ * named log4j implementation. If the behaviour of this class starts to deviate from that of the
+ * log4j backend in any significant way, this difference should be called out clearly in the
+ * documentation.
+ */
 final class Log4j2LoggerBackend extends LoggerBackend {
   private final Logger logger;