use custom log formatter for journald logging

src/main/java/app/attestation/server/AttestationServer.java

@@ -55,6 +55,8 @@
 import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
+import java.util.logging.ConsoleHandler;
+import java.util.logging.Handler;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 import java.util.zip.DataFormatException;
@@ -267,6 +269,11 @@ private static int getUserVersion(final SQLiteConnection conn) throws SQLiteExce
     public static void main(final String[] args) throws Exception {
         Logger.getLogger("com.almworks.sqlite4java").setLevel(Level.OFF);
 
+        Logger.getLogger("app.attestation").setUseParentHandlers(false);
+        final ConsoleHandler handler = new ConsoleHandler();
+        handler.setFormatter(new JournaldFormatter());
+        Logger.getLogger("app.attestation").addHandler(handler);
+
         final SQLiteConnection samplesConn = open(SAMPLES_DATABASE);
         try {
             final SQLiteStatement selectCreated = samplesConn.prepare("SELECT 1 FROM sqlite_master WHERE type='table' AND name='Samples'");

src/main/java/app/attestation/server/JournaldFormatter.java

@@ -0,0 +1,83 @@
+package app.attestation.server;
+
+import java.io.PrintWriter;
+import java.io.StringWriter;
+import java.util.Date;
+import java.util.logging.Formatter;
+import java.util.logging.Level;
+import java.util.logging.LogManager;
+import java.util.logging.LogRecord;
+
+class JournaldFormatter extends Formatter {
+    private static final int LEVEL_EMERG = 0;
+    private static final int LEVEL_ALERT = 1;
+    private static final int LEVEL_CRIT = 2;
+    private static final int LEVEL_ERR = 3;
+    private static final int LEVEL_WARNING = 4;
+    private static final int LEVEL_NOTICE = 5;
+    private static final int LEVEL_INFO = 6;
+    private static final int LEVEL_DEBUG = 7;
+
+    private static int toSyslogLevel(final Level level) {
+        final int value = level.intValue();
+        if (value >= 1300) {
+            return LEVEL_EMERG;
+        }
+        if (value >= 1200) {
+            return LEVEL_ALERT;
+        }
+        if (value >= 1100) {
+            return LEVEL_CRIT;
+        }
+        // Level.SEVERE 1000
+        if (value >= 1000) {
+            return LEVEL_ERR;
+        }
+        // Level.WARNING 900
+        if (value >= 900) {
+            return LEVEL_WARNING;
+        }
+        if (value >= 850) {
+            return LEVEL_NOTICE;
+        }
+        // Level.INFO 800
+        if (value >= 800) {
+            return LEVEL_INFO;
+        }
+        // Level.CONFIG 700
+        // Level.FINE 500
+        // Level.FINER 400
+        // Level.FINEST 300
+        return LEVEL_DEBUG;
+    }
+
+    public synchronized String format(LogRecord record) {
+        String source;
+        if (record.getSourceClassName() != null) {
+            source = record.getSourceClassName();
+            if (record.getSourceMethodName() != null) {
+               source += " " + record.getSourceMethodName();
+            }
+        } else {
+            source = record.getLoggerName();
+        }
+        final int level = toSyslogLevel(record.getLevel());
+        final String message = formatMessage(record);
+        String throwable = "";
+        if (record.getThrown() != null) {
+            final String newline = "\n<" + toSyslogLevel(record.getLevel()) + ">";
+            final StringWriter sw = new StringWriter();
+            final PrintWriter pw = new PrintWriter(sw) {
+                @Override
+                public void println() {
+                    write(newline);
+                }
+            };
+            pw.println();
+            record.getThrown().printStackTrace(pw);
+            pw.close();
+            throwable = sw.toString();
+        }
+        return String.format("<%s>%s: %s%s\n", level, source, message, throwable);
+    }
+}