[FIXED JENKINS-46659] Avoid Jetty timeouts by sending a ping-like packet every 10s while a CLI command is running.

cli/src/main/java/hudson/cli/CLI.java

@@ -704,6 +704,22 @@ public class CLI implements AutoCloseable {
                     }
                 }
             }.start();
+            new Thread("ping") { // JENKINS-46659
+                @Override
+                public void run() {
+                    try {
+                        Thread.sleep(10_000);
+                        while (!connection.complete) {
+                            LOGGER.fine("sending ping");
+                            connection.sendEncoding(Charset.defaultCharset().name()); // no-op at this point
+                            Thread.sleep(10_000);
+                        }
+                    } catch (IOException | InterruptedException x) {
+                        LOGGER.log(Level.WARNING, null, x);
+                    }
+                }
+
+            }.start();
             synchronized (connection) {
                 while (!connection.complete) {
                     connection.wait();

cli/src/main/java/hudson/cli/PlainCLIProtocol.java

@@ -34,7 +34,6 @@ import java.io.InputStream;
 import java.io.OutputStream;
 import java.nio.channels.ClosedChannelException;
 import java.nio.channels.ReadPendingException;
-import java.util.concurrent.TimeoutException;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 import org.apache.commons.io.IOUtils;
@@ -112,13 +111,6 @@ class PlainCLIProtocol {
                         } catch (EOFException x) {
                             handleClose();
                             break; // TODO verify that we hit EOF immediately, not partway into framelen
-                        } catch (IOException x) {
-                            if (x.getCause() instanceof TimeoutException) { // TODO on Tomcat this seems to be SocketTimeoutException
-                                LOGGER.log(Level.FINE, "ignoring idle timeout, perhaps from Jetty", x);
-                                continue;
-                            } else {
-                                throw x;
-                            }
                         }
                         if (framelen < 0) {
                             throw new IOException("corrupt stream: negative frame length");