Document Devtools' property defaults directly in reference docs

Closes gh-29406

buildSrc/src/main/java/org/springframework/boot/build/devtools/DocumentDevtoolsPropertyDefaults.java

@@ -0,0 +1,101 @@
+/*
+ * Copyright 2012-2022 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
+ *
+ *      https://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.build.devtools;
+
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Properties;
+import java.util.TreeMap;
+
+import org.gradle.api.DefaultTask;
+import org.gradle.api.artifacts.Configuration;
+import org.gradle.api.file.FileCollection;
+import org.gradle.api.file.RegularFileProperty;
+import org.gradle.api.tasks.InputFiles;
+import org.gradle.api.tasks.OutputFile;
+import org.gradle.api.tasks.TaskAction;
+
+/**
+ * Task for documenting Devtools' property defaults.
+ *
+ * @author Andy Wilkinson
+ */
+public class DocumentDevtoolsPropertyDefaults extends DefaultTask {
+
+	private Configuration devtools;
+
+	private final RegularFileProperty outputFile;
+
+	public DocumentDevtoolsPropertyDefaults() {
+		this.devtools = getProject().getConfigurations().create("devtools");
+		this.outputFile = getProject().getObjects().fileProperty();
+		this.outputFile.convention(getProject().getLayout().getBuildDirectory()
+				.file("docs/generated/using/devtools-property-defaults.adoc"));
+		Map<String, String> dependency = new HashMap<>();
+		dependency.put("path", ":spring-boot-project:spring-boot-devtools");
+		dependency.put("configuration", "propertyDefaults");
+		this.devtools.getDependencies().add(getProject().getDependencies().project(dependency));
+	}
+
+	@InputFiles
+	public FileCollection getDevtools() {
+		return this.devtools;
+	}
+
+	@OutputFile
+	public RegularFileProperty getOutputFile() {
+		return this.outputFile;
+	}
+
+	@TaskAction
+	void documentPropertyDefaults() throws IOException {
+		Map<String, String> properties = loadProperties();
+		documentProperties(properties);
+	}
+
+	private Map<String, String> loadProperties() throws IOException, FileNotFoundException {
+		Properties properties = new Properties();
+		Map<String, String> sortedProperties = new TreeMap<>();
+		try (FileInputStream stream = new FileInputStream(this.devtools.getSingleFile())) {
+			properties.load(stream);
+			for (String name : properties.stringPropertyNames()) {
+				sortedProperties.put(name, properties.getProperty(name));
+			}
+		}
+		return sortedProperties;
+	}
+
+	private void documentProperties(Map<String, String> properties) throws IOException {
+		try (PrintWriter writer = new PrintWriter(new FileWriter(this.outputFile.getAsFile().get()))) {
+			writer.println("[cols=\"3,1\"]");
+			writer.println("|===");
+			writer.println("| Name | Default Value");
+			properties.forEach((name, value) -> {
+				writer.println();
+				writer.printf("| `%s`%n", name);
+				writer.printf("| `%s`%n", value);
+			});
+			writer.println("|===");
+		}
+	}
+
+}

spring-boot-project/spring-boot-devtools/build.gradle

@@ -13,6 +13,13 @@ configurations {
 	intTestDependencies {
 		extendsFrom dependencyManagement
 	}
+	propertyDefaults
+}
+
+artifacts {
+	propertyDefaults(file("build/resources/main/org/springframework/boot/devtools/env/devtools-property-defaults.properties")) {
+		builtBy(processResources)
+	}
 }
 
 dependencies {

spring-boot-project/spring-boot-devtools/src/main/java/org/springframework/boot/devtools/env/DevToolsPropertyDefaultsPostProcessor.java

@@ -16,9 +16,11 @@
 
 package org.springframework.boot.devtools.env;
 
-import java.util.Collections;
+import java.io.IOException;
+import java.io.InputStream;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.Properties;
 
 import org.apache.commons.logging.Log;
 
@@ -62,23 +64,19 @@ public class DevToolsPropertyDefaultsPostProcessor implements EnvironmentPostPro
 	private static final Map<String, Object> PROPERTIES;
 
 	static {
-		Map<String, Object> properties = new HashMap<>();
-		properties.put("spring.thymeleaf.cache", "false");
-		properties.put("spring.freemarker.cache", "false");
-		properties.put("spring.groovy.template.cache", "false");
-		properties.put("spring.mustache.cache", "false");
-		properties.put("server.servlet.session.persistent", "true");
-		properties.put("spring.h2.console.enabled", "true");
-		properties.put("spring.web.resources.cache.period", "0");
-		properties.put("spring.web.resources.chain.cache", "false");
-		properties.put("spring.template.provider.cache", "false");
-		properties.put("spring.mvc.log-resolved-exception", "true");
-		properties.put("server.error.include-binding-errors", "ALWAYS");
-		properties.put("server.error.include-message", "ALWAYS");
-		properties.put("server.error.include-stacktrace", "ALWAYS");
-		properties.put("server.servlet.jsp.init-parameters.development", "true");
-		properties.put("spring.reactor.debug", "true");
-		PROPERTIES = Collections.unmodifiableMap(properties);
+		Properties properties = new Properties();
+		try (InputStream stream = DevToolsPropertyDefaultsPostProcessor.class
+				.getResourceAsStream("devtools-property-defaults.properties")) {
+			properties.load(stream);
+		}
+		catch (IOException ex) {
+			throw new RuntimeException("Failed to load devtools-property-defaults.properties", ex);
+		}
+		Map<String, Object> map = new HashMap<>();
+		for (String name : properties.stringPropertyNames()) {
+			map.put(name, properties.getProperty(name));
+		}
+		PROPERTIES = map;
 	}
 
 	@Override

spring-boot-project/spring-boot-devtools/src/main/resources/org/springframework/boot/devtools/env/devtools-property-defaults.properties

@@ -0,0 +1,15 @@
+server.error.include-binding-errors=always
+server.error.include-message=always
+server.error.include-stacktrace=always
+server.servlet.jsp.init-parameters.development=true
+server.servlet.session.persistent=true
+spring.freemarker.cache=false
+spring.groovy.template.cache=false
+spring.h2.console.enabled=true
+spring.mustache.cache=false
+spring.mvc.log-resolved-exception=true
+spring.reactor.debug=true
+spring.template.provider.cache=false
+spring.thymeleaf.cache=false
+spring.web.resources.cache.period=0
+spring.web.resources.chain.cache=false

spring-boot-project/spring-boot-devtools/src/test/java/org/springframework/boot/devtools/env/DevToolPropertiesIntegrationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2022 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.
@@ -18,6 +18,7 @@ package org.springframework.boot.devtools.env;
 
 import java.net.URL;
 import java.util.Collections;
+import java.util.Locale;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.Supplier;
 
@@ -107,9 +108,11 @@ class DevToolPropertiesIntegrationTests {
 		this.context = getContext(application::run);
 		ConfigurableEnvironment environment = this.context.getEnvironment();
 		String includeStackTrace = environment.getProperty("server.error.include-stacktrace");
-		assertThat(includeStackTrace).isEqualTo(ErrorProperties.IncludeAttribute.ALWAYS.toString());
+		assertThat(includeStackTrace)
+				.isEqualTo(ErrorProperties.IncludeAttribute.ALWAYS.toString().toLowerCase(Locale.ENGLISH));
 		String includeMessage = environment.getProperty("server.error.include-message");
-		assertThat(includeMessage).isEqualTo(ErrorProperties.IncludeAttribute.ALWAYS.toString());
+		assertThat(includeMessage)
+				.isEqualTo(ErrorProperties.IncludeAttribute.ALWAYS.toString().toLowerCase(Locale.ENGLISH));
 	}
 
 	protected ConfigurableApplicationContext getContext(Supplier<ConfigurableApplicationContext> supplier)

spring-boot-project/spring-boot-docs/build.gradle

@@ -243,6 +243,8 @@ task documentConfigurationProperties(type: org.springframework.boot.build.contex
 	outputDir = file("${buildDir}/docs/generated/")
 }
 
+task documentDevtoolsPropertyDefaults(type: org.springframework.boot.build.devtools.DocumentDevtoolsPropertyDefaults) {}
+
 tasks.withType(org.asciidoctor.gradle.jvm.AbstractAsciidoctorTask) {
 	dependsOn dependencyVersions
 	asciidoctorj {
@@ -296,6 +298,7 @@ syncDocumentationSourceForAsciidoctor {
 	dependsOn documentDependencyVersions
 	dependsOn documentVersionProperties
 	dependsOn documentConfigurationProperties
+	dependsOn documentDevtoolsPropertyDefaults
 	from("${buildDir}/docs/generated") {
 		into "asciidoc"
 	}

spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/devtools.adoc

@@ -67,13 +67,15 @@ Cache options are usually configured by settings in your `application.properties
 For example, Thymeleaf offers the configprop:spring.thymeleaf.cache[] property.
 Rather than needing to set these properties manually, the `spring-boot-devtools` module automatically applies sensible development-time configuration.
 
-Because you need more information about web requests while developing Spring MVC and Spring WebFlux applications, developer tools suggests you to enable `DEBUG` logging for the `web` logging group.
-This will give you information about the incoming request, which handler is processing it, the response outcome, etc.
-If you wish to log all request details (including potentially sensitive information), you can turn on the configprop:spring.mvc.log-request-details[] or configprop:spring.codec.log-request-details[] configuration properties.
+The following table lists all the properties that are applied:
+
+include::devtools-property-defaults.adoc[]
 
 NOTE: If you don't want property defaults to be applied you can set configprop:spring.devtools.add-properties[] to `false` in your `application.properties`.
 
-TIP: For a complete list of the properties that are applied by the devtools, see {spring-boot-devtools-module-code}/env/DevToolsPropertyDefaultsPostProcessor.java[DevToolsPropertyDefaultsPostProcessor].
+Because you need more information about web requests while developing Spring MVC and Spring WebFlux applications, developer tools suggests you to enable `DEBUG` logging for the `web` logging group.
+This will give you information about the incoming request, which handler is processing it, the response outcome, etc.
+If you wish to log all request details (including potentially sensitive information), you can turn on the configprop:spring.mvc.log-request-details[] or configprop:spring.codec.log-request-details[] configuration properties.