Merge pull request #17924 from scottmf

* gh-17924:
  Polish "Make dev tools' home directory configurable"
  Make dev tools' home directory configurable

Closes gh-17924

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

@@ -23,8 +23,11 @@ import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
+import java.util.Properties;
 import java.util.Set;
 import java.util.function.Function;
+import java.util.function.Supplier;
 
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.devtools.system.DevToolsEnablementDeducer;
@@ -59,6 +62,10 @@ public class DevToolsHomePropertiesPostProcessor implements EnvironmentPostProce
 
 	private static final Set<PropertySourceLoader> PROPERTY_SOURCE_LOADERS;
 
+	private final Properties systemProperties;
+
+	private final Map<String, String> environmentVariables;
+
 	static {
 		Set<PropertySourceLoader> propertySourceLoaders = new HashSet<>();
 		propertySourceLoaders.add(new PropertiesPropertySourceLoader());
@@ -68,6 +75,15 @@ public class DevToolsHomePropertiesPostProcessor implements EnvironmentPostProce
 		PROPERTY_SOURCE_LOADERS = Collections.unmodifiableSet(propertySourceLoaders);
 	}
 
+	public DevToolsHomePropertiesPostProcessor() {
+		this(System.getenv(), System.getProperties());
+	}
+
+	DevToolsHomePropertiesPostProcessor(Map<String, String> environmentVariables, Properties systemProperties) {
+		this.environmentVariables = environmentVariables;
+		this.systemProperties = systemProperties;
+	}
+
 	@Override
 	public void postProcessEnvironment(ConfigurableEnvironment environment, SpringApplication application) {
 		if (DevToolsEnablementDeducer.shouldEnable(Thread.currentThread())) {
@@ -122,9 +138,18 @@ public class DevToolsHomePropertiesPostProcessor implements EnvironmentPostProce
 	}
 
 	protected File getHomeDirectory() {
-		String home = System.getProperty("user.home");
-		if (StringUtils.hasLength(home)) {
-			return new File(home);
+		return getHomeDirectory(() -> this.environmentVariables.get("SPRING_DEVTOOLS_HOME"),
+				() -> this.systemProperties.getProperty("spring.devtools.home"),
+				() -> this.systemProperties.getProperty("user.home"));
+	}
+
+	@SafeVarargs
+	private final File getHomeDirectory(Supplier<String>... pathSuppliers) {
+		for (Supplier<String> pathSupplier : pathSuppliers) {
+			String path = pathSupplier.get();
+			if (StringUtils.hasText(path)) {
+				return new File(path);
+			}
 		}
 		return null;
 	}

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

@@ -21,6 +21,8 @@ import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.nio.file.Files;
+import java.util.Collections;
+import java.util.Map;
 import java.util.Properties;
 
 import org.junit.jupiter.api.BeforeEach;
@@ -47,9 +49,12 @@ class DevToolsHomePropertiesPostProcessorTests {
 
 	private File home;
 
+	private File customHome;
+
 	@BeforeEach
 	void setup(@TempDir File tempDir) {
-		this.home = tempDir;
+		this.home = new File(tempDir, "default-home");
+		this.customHome = new File(tempDir, "custom-home");
 		this.configDir = this.home + "/.config/spring-boot/";
 		new File(this.configDir).mkdirs();
 	}
@@ -63,6 +68,29 @@ class DevToolsHomePropertiesPostProcessorTests {
 		assertThat(environment.getProperty("abc")).isEqualTo("def");
 	}
 
+	@Test
+	void loadsPropertiesFromCustomHomeDirectorySetUsingSystemProperty() throws Exception {
+		Properties properties = new Properties();
+		properties.put("uvw", "xyz");
+		writeFile(properties, this.customHome, ".config/spring-boot/spring-boot-devtools.properties");
+		Properties systemProperties = new Properties();
+		systemProperties.setProperty("spring.devtools.home", this.customHome.getAbsolutePath());
+		ConfigurableEnvironment environment = getPostProcessedEnvironment(systemProperties);
+		assertThat(environment.getProperty("uvw")).isEqualTo("xyz");
+	}
+
+	@Test
+	void loadsPropertiesFromCustomHomeDirectorySetUsingEnvironmentVariable() throws Exception {
+		Properties properties = new Properties();
+		properties.put("uvw", "xyz");
+		writeFile(properties, this.customHome, ".config/spring-boot/spring-boot-devtools.properties");
+		Properties systemProperties = new Properties();
+		systemProperties.setProperty("spring.devtools.home", this.customHome.getAbsolutePath());
+		ConfigurableEnvironment environment = getPostProcessedEnvironment(
+				Collections.singletonMap("SPRING_DEVTOOLS_HOME", this.customHome.getAbsolutePath()));
+		assertThat(environment.getProperty("uvw")).isEqualTo("xyz");
+	}
+
 	@Test
 	void loadsPropertiesFromConfigDirectoryUsingProperties() throws Exception {
 		Properties properties = new Properties();
@@ -151,15 +179,39 @@ class DevToolsHomePropertiesPostProcessorTests {
 		assertThat(environment.getProperty("abc")).isNull();
 	}
 
-	private void writeFile(Properties properties, String s) throws IOException {
-		OutputStream out = new FileOutputStream(new File(this.home, s));
-		properties.store(out, null);
-		out.close();
+	private void writeFile(Properties properties, String path) throws IOException {
+		writeFile(properties, this.home, path);
+	}
+
+	private void writeFile(Properties properties, File home, String path) throws IOException {
+		File file = new File(home, path);
+		file.getParentFile().mkdirs();
+		try (OutputStream out = new FileOutputStream(file)) {
+			properties.store(out, null);
+		}
 	}
 
 	private ConfigurableEnvironment getPostProcessedEnvironment() throws Exception {
+		return getPostProcessedEnvironment(null, null);
+	}
+
+	private ConfigurableEnvironment getPostProcessedEnvironment(Properties systemProperties) throws Exception {
+		return getPostProcessedEnvironment(null, systemProperties);
+	}
+
+	private ConfigurableEnvironment getPostProcessedEnvironment(Map<String, String> env) throws Exception {
+		return getPostProcessedEnvironment(env, null);
+	}
+
+	private ConfigurableEnvironment getPostProcessedEnvironment(Map<String, String> env, Properties systemProperties)
+			throws Exception {
+		if (systemProperties == null) {
+			systemProperties = new Properties();
+			systemProperties.setProperty("user.home", this.home.getAbsolutePath());
+		}
 		ConfigurableEnvironment environment = new MockEnvironment();
-		MockDevToolHomePropertiesPostProcessor postProcessor = new MockDevToolHomePropertiesPostProcessor();
+		DevToolsHomePropertiesPostProcessor postProcessor = new DevToolsHomePropertiesPostProcessor(
+				(env != null) ? env : Collections.emptyMap(), systemProperties);
 		runPostProcessor(() -> postProcessor.postProcessEnvironment(environment, null));
 		return environment;
 	}
@@ -170,13 +222,4 @@ class DevToolsHomePropertiesPostProcessorTests {
 		thread.join();
 	}
 
-	private class MockDevToolHomePropertiesPostProcessor extends DevToolsHomePropertiesPostProcessor {
-
-		@Override
-		protected File getHomeDirectory() {
-			return DevToolsHomePropertiesPostProcessorTests.this.home;
-		}
-
-	}
-
 }

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

@@ -285,6 +285,9 @@ For example, to configure restart to always use a <<using#using.devtools.restart
 	      trigger-file: ".reloadtrigger"
 ----
 
+By default, `$HOME` is the user's home directory.
+To customize this location, set the `SPRING_DEVTOOLS_HOME` environment variable or the `spring.devtools.home` system property.
+
 NOTE: If devtools configuration files are not found in `$HOME/.config/spring-boot`, the root of the `$HOME` directory is searched for the presence of a `.spring-boot-devtools.properties` file.
 This allows you to share the devtools global configuration with applications that are on an older version of Spring Boot that does not support the `$HOME/.config/spring-boot` location.