Reduce code duplication of DailyLogRotateFileHandler + generalize logs compression

pandalib-util/src/main/java/fr/pandacube/lib/util/logs/DailyLogRotateFileHandler.java

@@ -0,0 +1,120 @@
+package fr.pandacube.lib.util.logs;
+
+import java.io.BufferedWriter;
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.text.DateFormat;
+import java.text.SimpleDateFormat;
+import java.util.Date;
+import java.util.logging.ErrorManager;
+import java.util.logging.Handler;
+import java.util.logging.LogRecord;
+import java.util.zip.GZIPOutputStream;
+
+/**
+ * A log handler that log file rotation in a specified folder.
+ * The current log file is latest.log, and the logs from previous days
+ * are in dated gzipped files in the same folder.
+ */
+public class DailyLogRotateFileHandler extends Handler {
+
+	/**
+	 * The format of the date to name the file.
+	 */
+	protected static final DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
+
+	private BufferedWriter currentFile = null;
+	private String currentFileDate = getCurrentDay();
+	private boolean closed = false;
+
+
+	@Override
+	public synchronized void close() throws SecurityException {
+		closed = true;
+		if (currentFile != null) try {
+			currentFile.close();
+		} catch (IOException ignored) {}
+	}
+
+	@Override
+	public synchronized void flush() {
+		if (closed) return;
+		if (currentFile == null) return;
+		try {
+			currentFile.flush();
+		} catch (IOException ignored) {}
+	}
+
+	@Override
+	public synchronized void publish(LogRecord record) {
+		if (closed || !isLoggable(record))
+			return;
+
+		if (currentFile == null || !currentFileDate.equals(getCurrentDay()))
+			changeFile();
+
+		if (currentFile == null)
+			return;
+
+		String formattedMessage;
+
+		try {
+			formattedMessage = getFormatter().format(record);
+		} catch (Exception ex) {
+			reportError(null, ex, ErrorManager.FORMAT_FAILURE);
+			return;
+		}
+
+		try {
+			currentFile.write(formattedMessage);
+			currentFile.flush();
+		} catch (Exception ex) {
+			reportError(null, ex, ErrorManager.WRITE_FAILURE);
+		}
+	}
+
+	private void changeFile() {
+		if (currentFile != null) {
+			try {
+				currentFile.flush();
+				currentFile.close();
+			} catch (IOException ignored) {}
+			File fileNewName = new File("logs/" + currentFileDate + ".log");
+			new File("logs/latest.log").renameTo(fileNewName);
+			new Thread(() -> compress(fileNewName), "Log compress Thread").start();
+		}
+
+		currentFileDate = getCurrentDay();
+		try {
+			File logDir = new File("logs");
+			logDir.mkdir();
+			currentFile = new BufferedWriter(new FileWriter("logs/latest.log", true));
+		} catch (SecurityException | IOException e) {
+			reportError("Erreur lors de l'initialisation d'un fichier log", e, ErrorManager.OPEN_FAILURE);
+			currentFile = null;
+		}
+
+	}
+
+	private String getCurrentDay() {
+		return dateFormat.format(new Date());
+	}
+
+
+	private void compress(File sourceFile) {
+		File destFile = new File(sourceFile.getParentFile(), sourceFile.getName() + ".gz");
+		if (destFile.exists())
+			destFile.delete();
+		try (GZIPOutputStream os = new GZIPOutputStream(new FileOutputStream(destFile))) {
+			Files.copy(sourceFile.toPath(), os);
+		} catch (IOException e) {
+			if (destFile.exists())
+				destFile.delete();
+			throw new RuntimeException(e);
+		}
+		sourceFile.delete();
+	}
+}