[PR] [server] Disable shutdown hook for log4j to ensure Fluss log in shutdown hook can be collected [fluss]

["LiebingYu (via GitHub)" <gi...@apache.org>]

LiebingYu opened a new pull request, #2020:
URL: https://github.com/apache/fluss/pull/2020

   
   
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Re: [PR] [server] Disable shutdown hook for log4j to ensure Fluss log in shutdown hook can be collected [fluss]

["wuchong (via GitHub)" <gi...@apache.org>]

wuchong commented on code in PR #2020:
URL: https://github.com/apache/fluss/pull/2020#discussion_r2563767745


##########
fluss-server/src/main/java/org/apache/fluss/server/utils/LogShutdownUtil.java:
##########
@@ -0,0 +1,38 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.fluss.server.utils;
+
+/** Utility class to shut down log system. */
+public class LogShutdownUtil {
+
+    public static void shutdownLogIfPossible() {
+        // To avoid binding to a specific logging implementation, we use reflection here.
+        try {
+            // To ensure that logs within the JVM shutdown hook can be printed when using Log4j2,
+            // Fluss has disabled Log4j2's shutdown hook; therefore, manual shutdown is required
+            // here.
+            Class<?> logManager = Class.forName("org.apache.logging.log4j.LogManager");
+            logManager.getMethod("shutdown").invoke(null);
+        } catch (ClassNotFoundException e) {
+            System.err.println("Class org.apache.logging.log4j.LogManager not found");
+        } catch (Exception e) {
+            System.err.println(
+                    "Error to invoke shutdown method of org.apache.logging.log4j.LogManager");

Review Comment:
   Use Logger to print the error messages, otherwise, if the reflection is failed, we can't find the error log (the `System.err` is not redirect to log files). 



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Re: [PR] [server] Disable shutdown hook for log4j to ensure Fluss log in shutdown hook can be collected [fluss]

["swuferhong (via GitHub)" <gi...@apache.org>]

swuferhong merged PR #2020:
URL: https://github.com/apache/fluss/pull/2020


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