Improve analysis of tomcat bind exception

Using the throwOnFailure attribute on the tomcat connector, we can now
determine if the underlying exception was a BindException and throw
a PortInUseException instead of the generic WebServerException.

Closes gh-7130

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/tomcat/TomcatReactiveWebServerFactory.java

@@ -115,6 +115,7 @@ public class TomcatReactiveWebServerFactory extends AbstractReactiveWebServerFac
 		File baseDir = (this.baseDirectory != null) ? this.baseDirectory : createTempDir("tomcat");
 		tomcat.setBaseDir(baseDir.getAbsolutePath());
 		Connector connector = new Connector(this.protocol);
+		connector.setThrowOnFailure(true);
 		tomcat.getService().addConnector(connector);
 		customizeConnector(connector);
 		tomcat.setConnector(connector);

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/tomcat/TomcatServletWebServerFactory.java

@@ -176,6 +176,7 @@ public class TomcatServletWebServerFactory extends AbstractServletWebServerFacto
 		File baseDir = (this.baseDirectory != null) ? this.baseDirectory : createTempDir("tomcat");
 		tomcat.setBaseDir(baseDir.getAbsolutePath());
 		Connector connector = new Connector(this.protocol);
+		connector.setThrowOnFailure(true);
 		tomcat.getService().addConnector(connector);
 		customizeConnector(connector);
 		tomcat.setConnector(connector);

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/tomcat/TomcatWebServer.java

@@ -16,6 +16,7 @@
 
 package org.springframework.boot.web.embedded.tomcat;
 
+import java.net.BindException;
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.Map;
@@ -37,6 +38,7 @@ import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.naming.ContextBindings;
 
+import org.springframework.boot.web.server.PortInUseException;
 import org.springframework.boot.web.server.WebServer;
 import org.springframework.boot.web.server.WebServerException;
 import org.springframework.util.Assert;
@@ -207,6 +209,9 @@ public class TomcatWebServer implements WebServer {
 				throw ex;
 			}
 			catch (Exception ex) {
+				if (findBindException(ex) != null) {
+					throw new PortInUseException(this.tomcat.getConnector().getPort());
+				}
 				throw new WebServerException("Unable to start embedded Tomcat server", ex);
 			}
 			finally {
@@ -229,6 +234,16 @@ public class TomcatWebServer implements WebServer {
 		}
 	}
 
+	private BindException findBindException(Throwable ex) {
+		if (ex == null) {
+			return null;
+		}
+		if (ex instanceof BindException) {
+			return (BindException) ex;
+		}
+		return findBindException(ex.getCause());
+	}
+
 	private void stopSilently() {
 		try {
 			stopTomcat();

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/embedded/jetty/JettyServletWebServerFactoryTests.java

@@ -338,9 +338,14 @@ class JettyServletWebServerFactoryTests extends AbstractServletWebServerFactoryT
 	}
 
 	@Override
-	protected void handleExceptionCausedByBlockedPort(RuntimeException ex, int blockedPort) {
+	protected void handleExceptionCausedByBlockedPortOnPrimaryConnector(RuntimeException ex, int blockedPort) {
 		assertThat(ex).isInstanceOf(PortInUseException.class);
 		assertThat(((PortInUseException) ex).getPort()).isEqualTo(blockedPort);
 	}
 
+	@Override
+	protected void handleExceptionCausedByBlockedPortOnSecondaryConnector(RuntimeException ex, int blockedPort) {
+		this.handleExceptionCausedByBlockedPortOnPrimaryConnector(ex, blockedPort);
+	}
+
 }

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/embedded/tomcat/TomcatReactiveWebServerFactoryTests.java

@@ -16,6 +16,9 @@
 
 package org.springframework.boot.web.embedded.tomcat;
 
+import java.io.IOException;
+import java.net.InetSocketAddress;
+import java.net.ServerSocket;
 import java.util.Arrays;
 
 import org.apache.catalina.Context;
@@ -32,10 +35,15 @@ import org.junit.jupiter.api.Test;
 import org.mockito.ArgumentCaptor;
 import org.mockito.InOrder;
 
+import org.springframework.boot.web.reactive.server.AbstractReactiveWebServerFactory;
 import org.springframework.boot.web.reactive.server.AbstractReactiveWebServerFactoryTests;
+import org.springframework.boot.web.server.PortInUseException;
+import org.springframework.boot.web.servlet.server.AbstractServletWebServerFactoryTests;
 import org.springframework.http.server.reactive.HttpHandler;
+import org.springframework.util.SocketUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.inOrder;
@@ -188,4 +196,41 @@ class TomcatReactiveWebServerFactoryTests extends AbstractReactiveWebServerFacto
 		assertThat(context.getClearReferencesThreadLocals()).isFalse();
 	}
 
+	@Test
+	protected void portClashOfPrimaryConnectorResultsInPortInUseException() throws IOException {
+		doWithBlockedPort((port) -> {
+			assertThatExceptionOfType(RuntimeException.class).isThrownBy(() -> {
+				AbstractReactiveWebServerFactory factory = getFactory();
+				factory.setPort(port);
+				this.webServer = factory.getWebServer(mock(HttpHandler.class));
+				this.webServer.start();
+			}).satisfies((ex) -> handleExceptionCausedByBlockedPortOnPrimaryConnector(ex, port));
+		});
+	}
+
+	protected final void doWithBlockedPort(AbstractServletWebServerFactoryTests.BlockedPortAction action)
+			throws IOException {
+		int port = SocketUtils.findAvailableTcpPort(40000);
+		ServerSocket serverSocket = new ServerSocket();
+		for (int i = 0; i < 10; i++) {
+			try {
+				serverSocket.bind(new InetSocketAddress(port));
+				break;
+			}
+			catch (Exception ex) {
+			}
+		}
+		try {
+			action.run(port);
+		}
+		finally {
+			serverSocket.close();
+		}
+	}
+
+	protected void handleExceptionCausedByBlockedPortOnPrimaryConnector(RuntimeException ex, int blockedPort) {
+		assertThat(ex).isInstanceOf(PortInUseException.class);
+		assertThat(((PortInUseException) ex).getPort()).isEqualTo(blockedPort);
+	}
+
 }

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/embedded/tomcat/TomcatServletWebServerFactoryTests.java

@@ -66,6 +66,7 @@ import org.mockito.ArgumentCaptor;
 import org.mockito.InOrder;
 
 import org.springframework.boot.testsupport.system.CapturedOutput;
+import org.springframework.boot.web.server.PortInUseException;
 import org.springframework.boot.web.server.WebServerException;
 import org.springframework.boot.web.servlet.server.AbstractServletWebServerFactory;
 import org.springframework.boot.web.servlet.server.AbstractServletWebServerFactoryTests;
@@ -326,18 +327,6 @@ class TomcatServletWebServerFactoryTests extends AbstractServletWebServerFactory
 		assertThat(connector.getURIEncoding()).isEqualTo("UTF-8");
 	}
 
-	@Test
-	void primaryConnectorPortClashThrowsWebServerException() throws IOException {
-		doWithBlockedPort((port) -> {
-			TomcatServletWebServerFactory factory = getFactory();
-			factory.setPort(port);
-			assertThatExceptionOfType(WebServerException.class).isThrownBy(() -> {
-				this.webServer = factory.getWebServer();
-				this.webServer.start();
-			});
-		});
-	}
-
 	@Test
 	void startupFailureDoesNotResultInUnstoppedThreadsBeingReported(CapturedOutput capturedOutput) throws IOException {
 		super.portClashOfPrimaryConnectorResultsInPortInUseException();
@@ -593,7 +582,13 @@ class TomcatServletWebServerFactoryTests extends AbstractServletWebServerFactory
 	}
 
 	@Override
-	protected void handleExceptionCausedByBlockedPort(RuntimeException ex, int blockedPort) {
+	protected void handleExceptionCausedByBlockedPortOnPrimaryConnector(RuntimeException ex, int blockedPort) {
+		assertThat(ex).isInstanceOf(PortInUseException.class);
+		assertThat(((PortInUseException) ex).getPort()).isEqualTo(blockedPort);
+	}
+
+	@Override
+	protected void handleExceptionCausedByBlockedPortOnSecondaryConnector(RuntimeException ex, int blockedPort) {
 		assertThat(ex).isInstanceOf(ConnectorStartFailedException.class);
 		assertThat(((ConnectorStartFailedException) ex).getPort()).isEqualTo(blockedPort);
 	}

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/embedded/undertow/UndertowServletWebServerFactoryTests.java

@@ -279,11 +279,16 @@ class UndertowServletWebServerFactoryTests extends AbstractServletWebServerFacto
 	}
 
 	@Override
-	protected void handleExceptionCausedByBlockedPort(RuntimeException ex, int blockedPort) {
+	protected void handleExceptionCausedByBlockedPortOnPrimaryConnector(RuntimeException ex, int blockedPort) {
 		assertThat(ex).isInstanceOf(PortInUseException.class);
 		assertThat(((PortInUseException) ex).getPort()).isEqualTo(blockedPort);
 		Undertow undertow = (Undertow) ReflectionTestUtils.getField(this.webServer, "undertow");
 		assertThat(undertow.getWorker()).isNull();
 	}
 
+	@Override
+	protected void handleExceptionCausedByBlockedPortOnSecondaryConnector(RuntimeException ex, int blockedPort) {
+		this.handleExceptionCausedByBlockedPortOnPrimaryConnector(ex, blockedPort);
+	}
+
 }

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/servlet/server/AbstractServletWebServerFactoryTests.java

@@ -831,7 +831,7 @@ public abstract class AbstractServletWebServerFactoryTests {
 				factory.setPort(port);
 				AbstractServletWebServerFactoryTests.this.webServer = factory.getWebServer();
 				AbstractServletWebServerFactoryTests.this.webServer.start();
-			}).satisfies((ex) -> handleExceptionCausedByBlockedPort(ex, port));
+			}).satisfies((ex) -> handleExceptionCausedByBlockedPortOnPrimaryConnector(ex, port));
 		});
 	}
 
@@ -843,7 +843,7 @@ public abstract class AbstractServletWebServerFactoryTests {
 				addConnector(port, factory);
 				AbstractServletWebServerFactoryTests.this.webServer = factory.getWebServer();
 				AbstractServletWebServerFactoryTests.this.webServer.start();
-			}).satisfies((ex) -> handleExceptionCausedByBlockedPort(ex, port));
+			}).satisfies((ex) -> handleExceptionCausedByBlockedPortOnSecondaryConnector(ex, port));
 		});
 	}
 
@@ -962,7 +962,10 @@ public abstract class AbstractServletWebServerFactoryTests {
 
 	protected abstract void addConnector(int port, AbstractServletWebServerFactory factory);
 
-	protected abstract void handleExceptionCausedByBlockedPort(RuntimeException ex, int blockedPort);
+	protected abstract void handleExceptionCausedByBlockedPortOnPrimaryConnector(RuntimeException ex, int blockedPort);
+
+	protected abstract void handleExceptionCausedByBlockedPortOnSecondaryConnector(RuntimeException ex,
+			int blockedPort);
 
 	private boolean doTestCompression(int contentSize, String[] mimeTypes, String[] excludedUserAgents)
 			throws Exception {