No longer log hostname during application start

Remove hostname logging since `InetAddress.getLocalHost().getHostName()`
causes a network lookup and can take a long time.

Closes gh-32908

buildSrc/src/main/java/org/springframework/boot/build/docs/ApplicationRunner.java

@@ -21,7 +21,6 @@ import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -134,10 +133,8 @@ public class ApplicationRunner extends DefaultTask {
 	private void awaitLogging(Process process) {
 		long end = System.currentTimeMillis() + 30000;
 		String expectedLogging = this.expectedLogging.get();
-		List<String> outputLines = Collections.emptyList();
 		while (System.currentTimeMillis() < end) {
-			outputLines = outputLines();
-			for (String line : outputLines) {
+			for (String line : outputLines()) {
 				if (line.contains(expectedLogging)) {
 					return;
 				}
@@ -146,10 +143,7 @@ public class ApplicationRunner extends DefaultTask {
 				throw new IllegalStateException("Process exited before '" + expectedLogging + "' was logged");
 			}
 		}
-		StringBuilder message = new StringBuilder(
-				"After 30 seconds '" + expectedLogging + "' had not be logged in the following output:\n\n");
-		outputLines.forEach((line) -> message.append(line).append("\n"));
-		throw new IllegalStateException(message.toString());
+		throw new IllegalStateException("'" + expectedLogging + "' was not logged within 30 seconds");
 	}
 
 	private List<String> outputLines() {
@@ -177,8 +171,8 @@ public class ApplicationRunner extends DefaultTask {
 	private List<String> normalize(List<String> lines) {
 		List<String> normalizedLines = lines;
 		Map<String, String> normalizations = new HashMap<>(this.normalizations);
-		normalizations.put("(Starting .* using Java .* on ).*( with PID [\\d]+ \\().*( started by ).*( in ).*(\\))",
-				"$1myhost$2" + this.applicationJar.get() + "$3myuser$4/opt/apps/$5");
+		normalizations.put("(Starting .* using Java .* with PID [\\d]+ \\().*( started by ).*( in ).*(\\))",
+				"$1" + this.applicationJar.get() + "$2myuser$3/opt/apps/$4");
 		for (Entry<String, String> normalization : normalizations.entrySet()) {
 			Pattern pattern = Pattern.compile(normalization.getKey());
 			normalizedLines = normalize(normalizedLines, pattern, normalization.getValue());

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/resources/org/springframework/boot/actuate/autoconfigure/endpoint/web/documentation/sample.log

@@ -6,7 +6,7 @@
  =========|_|==============|___/=/_/_/_/
  :: Spring Boot ::
 
-2017-08-08 17:12:30.910  INFO 19866 --- [           main] s.f.SampleWebFreeMarkerApplication       : Starting SampleWebFreeMarkerApplication on host.local with PID 19866
+2017-08-08 17:12:30.910  INFO 19866 --- [           main] s.f.SampleWebFreeMarkerApplication       : Starting SampleWebFreeMarkerApplication with PID 19866
 2017-08-08 17:12:30.913  INFO 19866 --- [           main] s.f.SampleWebFreeMarkerApplication       : No active profile set, falling back to default profiles: default
 2017-08-08 17:12:30.952  INFO 19866 --- [           main] ConfigServletWebServerApplicationContext : Refreshing org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@76b10754: startup date [Tue Aug 08 17:12:30 BST 2017]; root of context hierarchy
 2017-08-08 17:12:31.878  INFO 19866 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/StartupInfoLogger.java

@@ -17,12 +17,10 @@
 package org.springframework.boot;
 
 import java.lang.management.ManagementFactory;
-import java.net.InetAddress;
 import java.time.Duration;
 import java.util.concurrent.Callable;
 
 import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
 
 import org.springframework.aot.AotDetector;
 import org.springframework.boot.system.ApplicationHome;
@@ -42,10 +40,6 @@ import org.springframework.util.StringUtils;
  */
 class StartupInfoLogger {
 
-	private static final Log logger = LogFactory.getLog(StartupInfoLogger.class);
-
-	private static final long HOST_NAME_RESOLVE_THRESHOLD = 200;
-
 	private final Class<?> sourceClass;
 
 	StartupInfoLogger(Class<?> sourceClass) {
@@ -71,7 +65,6 @@ class StartupInfoLogger {
 		appendApplicationName(message);
 		appendVersion(message, this.sourceClass);
 		appendJavaVersion(message);
-		appendOn(message);
 		appendPid(message);
 		appendContext(message);
 		return message;
@@ -116,26 +109,6 @@ class StartupInfoLogger {
 		append(message, "v", () -> source.getPackage().getImplementationVersion());
 	}
 
-	private void appendOn(StringBuilder message) {
-		long startTime = System.currentTimeMillis();
-		append(message, "on ", () -> InetAddress.getLocalHost().getHostName());
-		long resolveTime = System.currentTimeMillis() - startTime;
-		if (resolveTime > HOST_NAME_RESOLVE_THRESHOLD) {
-			logger.warn(LogMessage.of(() -> {
-				StringBuilder warning = new StringBuilder();
-				warning.append("InetAddress.getLocalHost().getHostName() took ");
-				warning.append(resolveTime);
-				warning.append(" milliseconds to respond.");
-				warning.append(" Please verify your network configuration");
-				if (System.getProperty("os.name").toLowerCase().contains("mac")) {
-					warning.append(" (macOS machines may need to add entries to /etc/hosts)");
-				}
-				warning.append(".");
-				return warning;
-			}));
-		}
-	}
-
 	private void appendPid(StringBuilder message) {
 		append(message, "with PID ", ApplicationPid::new);
 	}

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/StartupInfoLoggerTests.java

@@ -16,8 +16,6 @@
 
 package org.springframework.boot;
 
-import java.net.InetAddress;
-import java.net.UnknownHostException;
 import java.time.Duration;
 
 import org.apache.commons.logging.Log;
@@ -43,28 +41,27 @@ class StartupInfoLoggerTests {
 	private final Log log = mock(Log.class);
 
 	@Test
-	void startingFormat() throws UnknownHostException {
+	void startingFormat() {
 		given(this.log.isInfoEnabled()).willReturn(true);
 		new StartupInfoLogger(getClass()).logStarting(this.log);
 		ArgumentCaptor<Object> captor = ArgumentCaptor.forClass(Object.class);
 		then(this.log).should().info(captor.capture());
 		assertThat(captor.getValue().toString()).contains("Starting " + getClass().getSimpleName() + " using Java "
-				+ System.getProperty("java.version") + " on " + InetAddress.getLocalHost().getHostName() + " with PID "
-				+ new ApplicationPid() + " (started by " + System.getProperty("user.name") + " in "
-				+ System.getProperty("user.dir") + ")");
+				+ System.getProperty("java.version") + " with PID " + new ApplicationPid() + " (started by "
+				+ System.getProperty("user.name") + " in " + System.getProperty("user.dir") + ")");
 	}
 
 	@Test
-	void startingFormatInAotMode() throws UnknownHostException {
+	void startingFormatInAotMode() {
 		System.setProperty("spring.aot.enabled", "true");
 		try {
 			given(this.log.isInfoEnabled()).willReturn(true);
 			new StartupInfoLogger(getClass()).logStarting(this.log);
 			ArgumentCaptor<Object> captor = ArgumentCaptor.forClass(Object.class);
 			then(this.log).should().info(captor.capture());
-			assertThat(captor.getValue().toString()).contains("Starting AOT-processed " + getClass().getSimpleName()
-					+ " using Java " + System.getProperty("java.version") + " on "
-					+ InetAddress.getLocalHost().getHostName() + " with PID " + new ApplicationPid() + " (started by "
+			assertThat(captor.getValue().toString())
+					.contains("Starting AOT-processed " + getClass().getSimpleName() + " using Java "
+							+ System.getProperty("java.version") + " with PID " + new ApplicationPid() + " (started by "
 							+ System.getProperty("user.name") + " in " + System.getProperty("user.dir") + ")");
 
 		}