Add file writer line sperator

core/src/main/java/org/apache/gravitino/audit/AuditLogManager.java

@@ -20,6 +20,7 @@
 package org.apache.gravitino.audit;
 
 import com.google.common.annotations.VisibleForTesting;
+import java.io.IOException;
 import java.util.Map;
 import org.apache.gravitino.Config;
 import org.apache.gravitino.Configs;
@@ -73,7 +74,11 @@ public void start() throws RuntimeException {}
 
           @Override
           public void stop() throws RuntimeException {
-            auditLogWriter.close();
+            try {
+              auditLogWriter.close();
+            } catch (IOException e) {
+              throw new RuntimeException(e);
+            }
           }
 
           @Override

core/src/main/java/org/apache/gravitino/audit/AuditLogWriter.java

@@ -55,9 +55,6 @@ default void write(Event event) {
     doWrite(getFormatter().format(event));
   }
 
-  /** Close the writer. */
-  void close();
-
   /**
    * Define the name of the writer, which related to audit writer configuration. Audit log writer
    * configuration start with: gravitino.audit.log.writer.${name}.*

core/src/main/java/org/apache/gravitino/audit/FileAuditWriter.java

@@ -20,15 +20,13 @@
 package org.apache.gravitino.audit;
 
 import com.google.common.annotations.VisibleForTesting;
-import com.google.common.base.Preconditions;
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.OutputStream;
 import java.io.OutputStreamWriter;
 import java.io.Writer;
 import java.nio.charset.StandardCharsets;
 import java.util.Map;
-import org.apache.commons.lang3.StringUtils;
 import org.apache.gravitino.exceptions.GravitinoRuntimeException;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -40,16 +38,19 @@
 public class FileAuditWriter implements AuditLogWriter {
   private static final Logger Log = LoggerFactory.getLogger(FileAuditWriter.class);
 
-  public static final String LOG_FILE_NAME_CONFIG = "name";
+  public static final String LOG_FILE_NAME_CONFIG = "fileName";
 
   public static final String FILE_IMMEDIATE_FLUSH_CONFIG = "immediateFlush";
 
+  public static final String LINE_SEPARATOR = "lineSeparator";
   private Formatter formatter;
   private Writer outWriter;
   @VisibleForTesting String fileName;
 
   boolean immediateFlush;
 
+  String lineSeparator;
+
   @Override
   public Formatter getFormatter() {
     return formatter;
@@ -58,11 +59,10 @@ public Formatter getFormatter() {
   @Override
   public void init(Formatter formatter, Map<String, String> properties) {
     this.formatter = formatter;
-    fileName = properties.getOrDefault(LOG_FILE_NAME_CONFIG, "default_gravitino_audit_log");
+    fileName = properties.getOrDefault(LOG_FILE_NAME_CONFIG, "gravitino_audit.log");
     immediateFlush =
         Boolean.parseBoolean(properties.getOrDefault(FILE_IMMEDIATE_FLUSH_CONFIG, "false"));
-    Preconditions.checkArgument(
-        StringUtils.isNotBlank(fileName), "FileAuditWriter: fileName is not set in configuration.");
+    lineSeparator = properties.getOrDefault(LINE_SEPARATOR, "\n");
     try {
       OutputStream outputStream = new FileOutputStream(fileName, true);
       outWriter = new OutputStreamWriter(outputStream, StandardCharsets.UTF_8);
@@ -76,7 +76,7 @@ public void init(Formatter formatter, Map<String, String> properties) {
   public void doWrite(AuditLog auditLog) {
     String log = auditLog.toString();
     try {
-      outWriter.write(log);
+      outWriter.write(log + lineSeparator);
       if (immediateFlush) {
         outWriter.flush();
       }

core/src/main/java/org/apache/gravitino/audit/SimpleAuditLog.java

@@ -20,6 +20,7 @@
 package org.apache.gravitino.audit;
 
 import java.text.SimpleDateFormat;
+import javax.annotation.Nullable;
 import lombok.Builder;
 
 /** The default implementation of the audit log. */
@@ -47,6 +48,7 @@ public Operation operation() {
   }
 
   @Override
+  @Nullable
   public String identifier() {
     return identifier;
   }

core/src/main/java/org/apache/gravitino/audit/SimpleFormatter.java

@@ -19,12 +19,11 @@
 
 package org.apache.gravitino.audit;
 
-import java.util.Objects;
 import org.apache.gravitino.audit.AuditLog.Status;
 import org.apache.gravitino.listener.api.event.Event;
 import org.apache.gravitino.listener.api.event.FailureEvent;
 
-/** The default implementation of the audit log. */
+/** The default formatter implementation of the audit log. */
 public class SimpleFormatter implements Formatter {
 
   @Override
@@ -33,10 +32,7 @@ public SimpleAuditLog format(Event event) {
     return SimpleAuditLog.builder()
         .user(event.user())
         .operation(AuditLog.Operation.fromEvent(event))
-        .identifier(
-            event.identifier() != null
-                ? Objects.requireNonNull(event.identifier()).toString()
-                : null)
+        .identifier(event.identifier() != null ? event.identifier().toString() : null)
         .timestamp(event.eventTime())
         .status(status)
         .build();

core/src/test/java/org/apache/gravitino/audit/TestAuditManager.java

@@ -49,7 +49,7 @@
 public class TestAuditManager {
   private static final Logger LOG = LoggerFactory.getLogger(TestAuditManager.class);
 
-  private static final String DEFAULT_FILE_NAME = "default_gravitino_audit_log";
+  private static final String DEFAULT_FILE_NAME = "gravitino_audit.log";
 
   @BeforeAll
   public void setup() {