SOLR-9365: Reduce noise in solr logs during graceful shutdown

solr/CHANGES.txt

@@ -158,6 +158,7 @@ Other Changes
 
 * SOLR-9498: Remove HDFS properties from DIH solrconfig.xml, as started in SOLR-6943 (Alexandre Rafalovitch)
 
+* SOLR-9365: Reduce noise in solr logs during graceful shutdown. (Cao Manh Dat via shalin)
 
 ==================  6.2.1 ==================
 

solr/core/src/java/org/apache/solr/cloud/ElectionContext.java

@@ -288,8 +288,12 @@ final class ShardLeaderElectionContext extends ShardLeaderElectionContextBase {
     String coreName = leaderProps.getStr(ZkStateReader.CORE_NAME_PROP);
     ActionThrottle lt;
     try (SolrCore core = cc.getCore(coreName)) {
-      if (core == null) {
+      if (core == null ) {
-        throw new SolrException(ErrorCode.SERVER_ERROR, "SolrCore not found:" + coreName + " in " + cc.getCoreNames());
+        if (cc.isShutDown()) {
+          return;
+        } else {
+          throw new SolrException(ErrorCode.SERVER_ERROR, "SolrCore not found:" + coreName + " in " + cc.getCoreNames());
+        }
       }
       MDCLoggingContext.setCore(core);
       lt = core.getUpdateHandler().getSolrCoreState().getLeaderThrottle();
@@ -325,9 +329,13 @@ final class ShardLeaderElectionContext extends ShardLeaderElectionContextBase {
       try (SolrCore core = cc.getCore(coreName)) {
         
         if (core == null) {
-          cancelElection();
+          if (!zkController.getCoreContainer().isShutDown())  {
-          throw new SolrException(ErrorCode.SERVER_ERROR,
+            cancelElection();
-              "SolrCore not found:" + coreName + " in " + cc.getCoreNames());
+            throw new SolrException(ErrorCode.SERVER_ERROR,
+                "SolrCore not found:" + coreName + " in " + cc.getCoreNames());
+          } else  {
+            return;
+          }
         }
         
         // should I be leader?

solr/core/src/java/org/apache/solr/cloud/LeaderElector.java

@@ -347,7 +347,9 @@ public  class LeaderElector {
         // am I the next leader?
         checkIfIamLeader(context, true);
       } catch (Exception e) {
-        log.warn("", e);
+        if (!zkClient.isClosed()) {
+          log.warn("", e);
+        }
       }
     }
   }

solr/core/src/java/org/apache/solr/cloud/OverseerTaskProcessor.java

@@ -176,7 +176,9 @@ public class OverseerTaskProcessor implements Runnable, Closeable {
     try {
       prioritizer.prioritizeOverseerNodes(myId);
     } catch (Exception e) {
-      log.error("Unable to prioritize overseer ", e);
+      if (!zkStateReader.getZkClient().isClosed()) {
+        log.error("Unable to prioritize overseer ", e);
+      }
     }
 
     // TODO: Make maxThreads configurable.

solr/solrj/src/java/org/apache/solr/common/cloud/SolrZkClient.java

@@ -32,6 +32,7 @@ import java.nio.charset.StandardCharsets;
 import java.nio.file.Path;
 import java.util.List;
 import java.util.concurrent.ExecutorService;
+import java.util.concurrent.RejectedExecutionException;
 import java.util.regex.Pattern;
 
 import org.apache.commons.io.FileUtils;
@@ -263,7 +264,14 @@ public class SolrZkClient implements Closeable {
       @Override
       public void process(final WatchedEvent event) {
         log.debug("Submitting job to respond to event " + event);
-        zkCallbackExecutor.submit(() -> watcher.process(event));
+        try {
+          zkCallbackExecutor.submit(() -> watcher.process(event));
+        } catch (RejectedExecutionException e) {
+          // If not a graceful shutdown
+          if (!isClosed()) {
+            throw e;
+          }
+        }
       }
     };
   }