jvz commented on code in PR #2249:
URL: https://github.com/apache/logging-log4j2/pull/2249#discussion_r1468029770
##########
log4j-api/src/main/java/org/apache/logging/log4j/status/StatusLogger.java:
##########
@@ -16,311 +16,590 @@
*/
package org.apache.logging.log4j.status;
-import java.io.Closeable;
+import static java.util.Objects.requireNonNull;
+
+import edu.umd.cs.findbugs.annotations.Nullable;
import java.io.IOException;
+import java.io.InputStream;
+import java.io.PrintStream;
+import java.net.URL;
+import java.time.format.DateTimeFormatter;
import java.util.ArrayList;
import java.util.Collection;
+import java.util.Collections;
+import java.util.Iterator;
import java.util.List;
+import java.util.Properties;
import java.util.Queue;
import java.util.concurrent.ConcurrentLinkedQueue;
-import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReadWriteLock;
-import java.util.concurrent.locks.ReentrantLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
import org.apache.logging.log4j.Level;
import org.apache.logging.log4j.Marker;
import org.apache.logging.log4j.message.Message;
import org.apache.logging.log4j.message.MessageFactory;
import org.apache.logging.log4j.message.ParameterizedNoReferenceMessageFactory;
-import org.apache.logging.log4j.simple.SimpleLogger;
-import org.apache.logging.log4j.simple.SimpleLoggerContext;
import org.apache.logging.log4j.spi.AbstractLogger;
import org.apache.logging.log4j.util.Constants;
-import org.apache.logging.log4j.util.PropertiesUtil;
/**
- * Records events that occur in the logging system. By default, only error
messages are logged to {@link System#err}.
- * Normally, the Log4j StatusLogger is configured via the root {@code
<Configuration status="LEVEL"/>} node in a Log4j
- * configuration file. However, this can be overridden via a system property
named
- * {@value #DEFAULT_STATUS_LISTENER_LEVEL} and will work with any Log4j
provider.
- *
- * @see SimpleLogger
- * @see SimpleLoggerContext
+ * Records events that occur in the logging system.
+ * {@link StatusLogger} is expected to be a standalone, self-sufficient
component that the logging system can rely on for low-level logging purposes.
+ * <h3>Listeners</h3>
+ * <p>
+ * Each recorded event will first get buffered and used to notify the
registered {@link StatusListener}s.
+ * Listener registry is always initialized with a <em>default listener</em>,
which is a {@link StatusConsoleListener}.
+ * </p>
+ * <p>
+ * You can programmatically register listeners using {@link
#registerListener(StatusListener)} method.
+ * </p>
+ * <h3>Configuration</h3>
+ * <p>
+ * The {@code StatusLogger} can be configured in following ways:
+ * </p>
+ * <ol>
+ * <li>Passing system properties to the Java process (e.g., {@code
-Dlog4j2.StatusLogger.level=INFO})</li>
+ * <li>Providing properties in a {@value StatusLogger#PROPERTIES_FILE_NAME}
file in the classpath</li>
+ * <li>Using Log4j configuration (i.e., {@code <Configuration status="WARN"
dest="out">} in a {@code log4j2.xml} in the classpath)</li>
+ * </ol>
+ * <p>
+ * It is crucial to understand that there is a time between the first {@code
StatusLogger} access and a configuration file (e.g., {@code log4j2.xml}) read.
+ * Consider the following example:
+ * </p>
+ * <ol>
+ * <li>The default level is {@code ERROR}</li>
+ * <li>You have <Configuration status="WARN">} in your {@code log4j2.xml}</li>
+ * <li>Until your {@code log4j2.xml} configuration is read, the effective
level will be {@code ERROR}</li>
+ * <li>Once your {@code log4j2.xml} configuration is read, the effective level
will be {@code WARN} as you configured</li>
+ * </ol>
+ * <p>
+ * Hence, unless you use either system properties or {@value
StatusLogger#PROPERTIES_FILE_NAME} file in the classpath, there is a time
window that only the defaults will be effective.
+ * </p>
+ * <p>
+ * {@code StatusLogger} is designed as a singleton class accessed statically.
+ * If you are running an application containing multiple Log4j configurations
(e.g., in a servlet environment with multiple containers) and you happen to
have differing {@code StatusLogger} configurations (e.g, one {@code log4j2.xml}
containing {@code <Configuration status="ERROR">} while the other {@code
<Configuration status="INFO">}), the last loaded configuration will be
effective one.
+ * </p>
+ * <h3>Debug mode</h3>
+ * <p>
+ * When the {@value Constants#LOG4J2_DEBUG} system property is present, any
level-related filtering will be skipped and all events will be notified to
listeners.
+ * </p>
*/
-public final class StatusLogger extends AbstractLogger {
+public class StatusLogger extends AbstractLogger {
Review Comment:
Since this class is still serializable in 2.x, I suggest using a
serialization proxy for this logger rather than relying on any particular
`transient` or non-transient fields. That way, you can serialize the
configuration (which is currently not serializable), transform the status data
entries into a basic array (or `ArrayList`), and exclude any fields that can be
constructed from the proxy state.
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: notifications-unsubscr...@logging.apache.org
For queries about this service, please contact Infrastructure at:
us...@infra.apache.org
