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Log4j2 debounce filter example (untested)
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| import org.apache.logging.log4j.core.config.plugins.Plugin; | |
| import org.apache.logging.log4j.core.config.plugins.PluginAttribute; | |
| import org.apache.logging.log4j.core.config.plugins.PluginFactory; | |
| // Register the plugin to allow it to be used later | |
| @Plugin(name = "DebounceFilter", category = "Core", elementType = "filter", printObject = true) | |
| public class DebounceFilterPlugin extends DebounceFilter { | |
| // Factory method for creating the filter from configuration | |
| @PluginFactory | |
| public static DebounceFilter createFilter(@PluginAttribute("debounceTimeMs") long debounceTimeMs) { | |
| return new DebounceFilter(debounceTimeMs); | |
| } | |
| } |
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| <Configuration status="WARN"> | |
| <Appenders> | |
| <Console name="Console" target="SYSTEM_OUT"> | |
| <PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/> | |
| </Console> | |
| </Appenders> | |
| <Loggers> | |
| <!-- Root logger without the debounce filter --> | |
| <Root level="info"> | |
| <AppenderRef ref="Console"/> | |
| </Root> | |
| <!-- Logger specifically for classes which may log a high level of warn messages --> | |
| <Logger name="com.myorg.myproduct.MySpecificClass" level="warn" additivity="false"> | |
| <AppenderRef ref="Console"/> | |
| <Filters> | |
| <!-- Debounce filter applied only to this logger --> | |
| <Filter type="DebounceFilter" debounceTimeMs="60000" onMatch="NEUTRAL" onMismatch="DENY"/> | |
| </Filters> | |
| </Logger> | |
| </Loggers> | |
| </Configuration> |
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| import org.apache.logging.log4j.core.Filter; | |
| import org.apache.logging.log4j.core.LogEvent; | |
| import org.apache.logging.log4j.core.filter.AbstractFilter; | |
| import org.apache.logging.log4j.core.filter.Filter.Result; | |
| import java.util.Map; | |
| import java.util.concurrent.ConcurrentHashMap; | |
| public class DebounceFilter extends AbstractFilter { | |
| // Class to hold details about a log message's debouncing status | |
| private static class LogEntry { | |
| long firstLoggedTime; // First time the message was logged | |
| long lastLoggedTime; // Last time the message was logged | |
| int debounceCount; // Number of times the message was suppressed | |
| } | |
| // Map to store log messages and their debouncing information | |
| private final Map<String, LogEntry> messageLogEntries = new ConcurrentHashMap<>(); | |
| // Time window for debounce in milliseconds (e.g., 1 minute = 60000 ms) | |
| private final long debounceTimeMs; | |
| // Constructor to set debounce time | |
| public DebounceFilter(long debounceTimeMs) { | |
| this.debounceTimeMs = debounceTimeMs; | |
| } | |
| @Override | |
| public Result filter(LogEvent event) { | |
| // Get the log message | |
| String message = event.getMessage().getFormattedMessage(); | |
| long currentTime = System.currentTimeMillis(); | |
| // Get or create a LogEntry for this message | |
| LogEntry logEntry = messageLogEntries.computeIfAbsent(message, k -> new LogEntry()); | |
| // If this is the first time the message is being logged, initialize the entry | |
| if (logEntry.firstLoggedTime == 0) { | |
| logEntry.firstLoggedTime = currentTime; | |
| logEntry.lastLoggedTime = currentTime; | |
| logEntry.debounceCount = 0; | |
| return Result.NEUTRAL; // Log the message | |
| } | |
| // Check if enough time has passed since the last time the message was logged | |
| if ((currentTime - logEntry.lastLoggedTime) > debounceTimeMs) { | |
| // Log the original message along with the debounce count and duration | |
| if (logEntry.debounceCount > 0) { | |
| String debounceInfo = String.format( | |
| "[%d suppressed occurrences over %d ms]", | |
| logEntry.debounceCount, | |
| currentTime - logEntry.firstLoggedTime | |
| ); | |
| // Log the message with debounce info (you can decide how to log this, like appending to the original message) | |
| System.out.println(message + " " + debounceInfo); | |
| } | |
| // Reset the debounce state for the message | |
| logEntry.firstLoggedTime = currentTime; | |
| logEntry.lastLoggedTime = currentTime; | |
| logEntry.debounceCount = 0; | |
| return Result.NEUTRAL; // Log the message | |
| } else { | |
| // Debounce the message: update the last logged time and increment the debounce count | |
| logEntry.lastLoggedTime = currentTime; | |
| logEntry.debounceCount++; | |
| return Result.DENY; // Suppress the message | |
| } | |
| } | |
| // Factory method for the filter configuration (optional, can be customized) | |
| public static DebounceFilter createFilter(long debounceTimeMs) { | |
| return new DebounceFilter(debounceTimeMs); | |
| } | |
| } |
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