Defer devtools logging

Defer logging from devtools classes until the context is prepared.

Closes gh-14453

Author: philwebb

spring-boot-project/spring-boot-devtools/src/main/java/org/springframework/boot/devtools/logger/DevToolsLogFactory.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright 2018-2018 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.devtools.logger;
+
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+import org.springframework.boot.context.event.ApplicationPreparedEvent;
+import org.springframework.boot.logging.DeferredLog;
+import org.springframework.context.ApplicationListener;
+import org.springframework.data.domain.AbstractPageRequest;
+
+/**
+ * Devtools deferred logging support.
+ *
+ * @author Phillip Webb
+ * @since 2.1.0
+ */
+public final class DevToolsLogFactory {
+
+	private static final Map<DeferredLog, Class<?>> logs = new LinkedHashMap<>();
+
+	private DevToolsLogFactory() {
+	}
+
+	/**
+	 * Get a {@link DeferredLog} instance for the specified source that will be
+	 * automatically {@link DeferredLog#switchTo(Class) switched} then the
+	 * {@link AbstractPageRequest context is prepared}.
+	 * @param source the source for logging
+	 * @return a {@link DeferredLog} instance
+	 */
+	public static DeferredLog getLog(Class<?> source) {
+		synchronized (logs) {
+			DeferredLog log = new DeferredLog();
+			logs.put(log, source);
+			return log;
+		}
+	}
+
+	/**
+	 * Listener used to log and switch when the context is ready.
+	 */
+	static class Listener implements ApplicationListener<ApplicationPreparedEvent> {
+
+		@Override
+		public void onApplicationEvent(ApplicationPreparedEvent event) {
+			synchronized (logs) {
+				logs.forEach((log, source) -> log.switchTo(source));
+				logs.clear();
+			}
+		}
+
+	}
+
+}

spring-boot-project/spring-boot-devtools/src/main/java/org/springframework/boot/devtools/restart/ChangeableUrls.java

@@ -33,8 +33,8 @@
 import java.util.stream.Stream;
 
 import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
 
+import org.springframework.boot.devtools.logger.DevToolsLogFactory;
 import org.springframework.boot.devtools.settings.DevToolsSettings;
 import org.springframework.util.StringUtils;
 
@@ -46,7 +46,7 @@
  */
 final class ChangeableUrls implements Iterable<URL> {
 
-	private static final Log logger = LogFactory.getLog(ChangeableUrls.class);
+	private static final Log logger = DevToolsLogFactory.getLog(ChangeableUrls.class);
 
 	private final List<URL> urls;
 

spring-boot-project/spring-boot-devtools/src/main/java/org/springframework/boot/devtools/settings/DevToolsSettings.java

@@ -25,8 +25,8 @@
 import java.util.regex.Pattern;
 
 import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
 
+import org.springframework.boot.devtools.logger.DevToolsLogFactory;
 import org.springframework.core.io.UrlResource;
 import org.springframework.core.io.support.PropertiesLoaderUtils;
 
@@ -43,7 +43,7 @@ public class DevToolsSettings {
 	 */
 	public static final String SETTINGS_RESOURCE_LOCATION = "META-INF/spring-devtools.properties";
 
-	private static final Log logger = LogFactory.getLog(DevToolsSettings.class);
+	private static final Log logger = DevToolsLogFactory.getLog(DevToolsSettings.class);
 
 	private static DevToolsSettings settings;
 

spring-boot-project/spring-boot-devtools/src/main/resources/META-INF/spring.factories

@@ -4,7 +4,8 @@ org.springframework.boot.devtools.restart.RestartScopeInitializer
 
 # Application Listeners
 org.springframework.context.ApplicationListener=\
-org.springframework.boot.devtools.restart.RestartApplicationListener
+org.springframework.boot.devtools.restart.RestartApplicationListener,\
+org.springframework.boot.devtools.logger.DevToolsLogFactory.Listener
 
 # Auto Configure
 org.springframework.boot.autoconfigure.EnableAutoConfiguration=\