ZOOKEEPER-3188: better shutdown for executors (following PR comments)

Mate Szalay-Beko · Mate Szalay-Beko · commit ed31d2ce9349 · 2019-10-04T14:16:42.000+02:00
diff --git a/zookeeper-server/src/main/java/org/apache/zookeeper/server/quorum/Leader.java b/zookeeper-server/src/main/java/org/apache/zookeeper/server/quorum/Leader.java
@@ -47,6 +47,7 @@
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.stream.Collectors;
@@ -449,10 +450,17 @@ public void run() {
                 try {
                     latch.await();
                 } catch (InterruptedException ie) {
-                    LOG.error("Interrupted while sleeping. Ignoring exception", ie);
+                    LOG.error("Interrupted while sleeping in LearnerCnxAcceptor.", ie);
                 } finally {
                     closeSockets();
-                    executor.shutdownNow();
+                    executor.shutdown();
+                    try {
+                        if (!executor.awaitTermination(1, TimeUnit.SECONDS)) {
+                            LOG.error("not all the LearnerCnxAcceptorHandler terminated properly");
+                        }
+                    } catch (InterruptedException ie) {
+                        LOG.error("Interrupted while terminating LearnerCnxAcceptor.", ie);
+                    }
                 }
             }
         }
diff --git a/zookeeper-server/src/main/java/org/apache/zookeeper/server/quorum/Learner.java b/zookeeper-server/src/main/java/org/apache/zookeeper/server/quorum/Learner.java
@@ -37,6 +37,7 @@
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicReference;
 import javax.net.ssl.SSLSocket;
 import org.apache.jute.BinaryInputArchive;
@@ -272,7 +273,14 @@ protected void connectToLeader(MultipleAddresses addr, String hostname) throws I
         } catch (InterruptedException e) {
             LOG.warn("Interrupted while trying to connect to Leader", e);
         } finally {
-            executor.shutdownNow();
+            executor.shutdown();
+            try {
+                if (!executor.awaitTermination(1, TimeUnit.SECONDS)) {
+                    LOG.error("not all the LeaderConnector terminated properly");
+                }
+            } catch (InterruptedException ie) {
+                LOG.error("Interrupted while terminating LeaderConnector executor.", ie);
+            }
         }
 
         if (socket.get() == null) {
