Add support for wildcard locations for properties and YAML files

Closes gh-19909

Author: mbhave

spring-boot-project/spring-boot-docs/src/docs/asciidoc/spring-boot-features.adoc

@@ -396,6 +396,10 @@ On your application classpath (for example, inside your jar) you can have an `ap
 When running in a new environment, an `application.properties` file can be provided outside of your jar that overrides the `name`.
 For one-off testing, you can launch with a specific command line switch (for example, `java -jar app.jar --name="Spring"`).
 
+NOTE: Spring Boot also supports wildcard locations when loading configuration files.
+By default, a wildcard location of `config/*/` outside of your jar is supported.
+Wildcard locations are also supported when specifying `spring.config.additional-location` and `spring.config.location`.
+
 [[boot-features-external-config-application-json]]
 [TIP]
 ====
@@ -492,10 +496,11 @@ If `spring.config.location` contains directories (as opposed to files), they sho
 Files specified in `spring.config.location` are used as-is, with no support for profile-specific variants, and are overridden by any profile-specific properties.
 
 Config locations are searched in reverse order.
-By default, the configured locations are `classpath:/,classpath:/config/,file:./,file:./config/`.
+By default, the configured locations are `classpath:/,classpath:/config/,file:./,file:./config/*/,file:./config/`.
 The resulting search order is the following:
 
 . `file:./config/`
+. `file:./config/*/`
 . `file:./`
 . `classpath:/config/`
 . `classpath:/`
@@ -513,6 +518,7 @@ For example, if additional locations of `classpath:/custom-config/,file:./custom
 . `file:./custom-config/`
 . `classpath:custom-config/`
 . `file:./config/`
+. `file:./config/*/`
 . `file:./`
 . `classpath:/config/`
 . `classpath:/`

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/config/ConfigFileApplicationListener.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -62,6 +62,7 @@
 import org.springframework.core.io.DefaultResourceLoader;
 import org.springframework.core.io.Resource;
 import org.springframework.core.io.ResourceLoader;
+import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
 import org.springframework.core.io.support.SpringFactoriesLoader;
 import org.springframework.util.Assert;
 import org.springframework.util.CollectionUtils;
@@ -75,6 +76,7 @@
  * 'application.properties' and/or 'application.yml' files in the following locations:
  * <ul>
  * <li>file:./config/</li>
+ * <li>file:./config/{@literal *}/</li>
  * <li>file:./</li>
  * <li>classpath:config/</li>
  * <li>classpath:</li>
@@ -107,7 +109,7 @@ public class ConfigFileApplicationListener implements EnvironmentPostProcessor,
 	private static final String DEFAULT_PROPERTIES = "defaultProperties";
 
 	// Note the order is from least to most specific (last one wins)
-	private static final String DEFAULT_SEARCH_LOCATIONS = "classpath:/,classpath:/config/,file:./,file:./config/";
+	private static final String DEFAULT_SEARCH_LOCATIONS = "classpath:/,classpath:/config/,file:./,file:./config/*/,file:./config/";
 
 	private static final String DEFAULT_NAMES = "application";
 
@@ -158,6 +160,8 @@ public class ConfigFileApplicationListener implements EnvironmentPostProcessor,
 
 	private final DeferredLog logger = new DeferredLog();
 
+	private static final Resource[] EMPTY_RESOURCES = {};
+
 	private String searchLocations;
 
 	private String names;
@@ -299,6 +303,8 @@ private class Loader {
 
 		private final ResourceLoader resourceLoader;
 
+		private final PathMatchingResourcePatternResolver patternResolver;
+
 		private final List<PropertySourceLoader> propertySourceLoaders;
 
 		private Deque<Profile> profiles;
@@ -317,6 +323,7 @@ private class Loader {
 			this.resourceLoader = (resourceLoader != null) ? resourceLoader : new DefaultResourceLoader();
 			this.propertySourceLoaders = SpringFactoriesLoader.loadFactories(PropertySourceLoader.class,
 					getClass().getClassLoader());
+			this.patternResolver = new PathMatchingResourcePatternResolver(this.resourceLoader);
 		}
 
 		void load() {
@@ -497,47 +504,51 @@ private void loadForFileExtension(PropertySourceLoader loader, String prefix, St
 		private void load(PropertySourceLoader loader, String location, Profile profile, DocumentFilter filter,
 				DocumentConsumer consumer) {
 			try {
-				Resource resource = this.resourceLoader.getResource(location);
-				if (resource == null || !resource.exists()) {
-					if (this.logger.isTraceEnabled()) {
-						StringBuilder description = getDescription("Skipped missing config ", location, resource,
-								profile);
-						this.logger.trace(description);
+				Resource[] resources = getResources(location);
+				for (Resource resource : resources) {
+					if (resource == null || !resource.exists()) {
+						if (this.logger.isTraceEnabled()) {
+							StringBuilder description = getDescription("Skipped missing config ", location, resource,
+									profile);
+							this.logger.trace(description);
+						}
+						return;
 					}
-					return;
-				}
-				if (!StringUtils.hasText(StringUtils.getFilenameExtension(resource.getFilename()))) {
-					if (this.logger.isTraceEnabled()) {
-						StringBuilder description = getDescription("Skipped empty config extension ", location,
-								resource, profile);
-						this.logger.trace(description);
+					if (!StringUtils.hasText(StringUtils.getFilenameExtension(resource.getFilename()))) {
+						if (this.logger.isTraceEnabled()) {
+							StringBuilder description = getDescription("Skipped empty config extension ", location,
+									resource, profile);
+							this.logger.trace(description);
+						}
+						return;
 					}
-					return;
-				}
-				String name = "applicationConfig: [" + location + "]";
-				List<Document> documents = loadDocuments(loader, name, resource);
-				if (CollectionUtils.isEmpty(documents)) {
-					if (this.logger.isTraceEnabled()) {
-						StringBuilder description = getDescription("Skipped unloaded config ", location, resource,
-								profile);
-						this.logger.trace(description);
+					String name = (location.contains("*")) ? "applicationConfig: [" + resource.toString() + "]"
+							: "applicationConfig: [" + location + "]";
+					List<Document> documents = loadDocuments(loader, name, resource);
+					if (CollectionUtils.isEmpty(documents)) {
+						if (this.logger.isTraceEnabled()) {
+							StringBuilder description = getDescription("Skipped unloaded config ", location, resource,
+									profile);
+							this.logger.trace(description);
+						}
+						return;
 					}
-					return;
-				}
-				List<Document> loaded = new ArrayList<>();
-				for (Document document : documents) {
-					if (filter.match(document)) {
-						addActiveProfiles(document.getActiveProfiles());
-						addIncludedProfiles(document.getIncludeProfiles());
-						loaded.add(document);
+					List<Document> loaded = new ArrayList<>();
+					for (Document document : documents) {
+						if (filter.match(document)) {
+							addActiveProfiles(document.getActiveProfiles());
+							addIncludedProfiles(document.getIncludeProfiles());
+							loaded.add(document);
+						}
 					}
-				}
-				Collections.reverse(loaded);
-				if (!loaded.isEmpty()) {
-					loaded.forEach((document) -> consumer.accept(profile, document));
-					if (this.logger.isDebugEnabled()) {
-						StringBuilder description = getDescription("Loaded config file ", location, resource, profile);
-						this.logger.debug(description);
+					Collections.reverse(loaded);
+					if (!loaded.isEmpty()) {
+						loaded.forEach((document) -> consumer.accept(profile, document));
+						if (this.logger.isDebugEnabled()) {
+							StringBuilder description = getDescription("Loaded config file ", location, resource,
+									profile);
+							this.logger.debug(description);
+						}
 					}
 				}
 			}
@@ -546,6 +557,15 @@ private void load(PropertySourceLoader loader, String location, Profile profile,
 			}
 		}
 
+		private Resource[] getResources(String location) {
+			try {
+				return this.patternResolver.getResources(location);
+			}
+			catch (IOException ex) {
+				return EMPTY_RESOURCES;
+			}
+		}
+
 		private void addIncludedProfiles(Set<Profile> includeProfiles) {
 			LinkedList<Profile> existingProfiles = new LinkedList<>(this.profiles);
 			this.profiles.clear();

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/config/ConfigFileApplicationListenerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -58,6 +58,7 @@
 import org.springframework.core.env.SimpleCommandLinePropertySource;
 import org.springframework.core.env.StandardEnvironment;
 import org.springframework.core.io.ByteArrayResource;
+import org.springframework.core.io.ClassPathResource;
 import org.springframework.core.io.Resource;
 import org.springframework.core.io.ResourceLoader;
 import org.springframework.test.context.support.TestPropertySourceUtils;
@@ -73,6 +74,7 @@
  * @author Phillip Webb
  * @author Dave Syer
  * @author Eddú Meléndez
+ * @author Madhura Bhave
  */
 @ExtendWith(OutputCaptureExtension.class)
 class ConfigFileApplicationListenerTests {
@@ -109,7 +111,7 @@ public String getFilename() {
 						}
 					};
 				}
-				return null;
+				return new ClassPathResource("doesnotexist");
 			}
 
 			@Override
@@ -1001,6 +1003,32 @@ void whenConfigLocationSpecifiesFolderConfigFileProcessingContinues() {
 		this.initializer.postProcessEnvironment(this.environment, this.application);
 	}
 
+	@Test
+	void locationsWithWildcardFoldersShouldLoadAllFilesThatMatch() {
+		String location = "file:src/test/resources/config/*/";
+		TestPropertySourceUtils.addInlinedPropertiesToEnvironment(this.environment,
+				"spring.config.location=" + location);
+		this.initializer.setSearchNames("testproperties");
+		this.initializer.postProcessEnvironment(this.environment, this.application);
+		String a = this.environment.getProperty("a.property");
+		String b = this.environment.getProperty("b.property");
+		assertThat(a).isEqualTo("apple");
+		assertThat(b).isEqualTo("ball");
+	}
+
+	@Test
+	void locationsWithWildcardFilesShouldLoadAllFilesThatMatch() {
+		String location = "file:src/test/resources/config/*/testproperties.properties";
+		TestPropertySourceUtils.addInlinedPropertiesToEnvironment(this.environment,
+				"spring.config.location=" + location);
+		this.initializer.setSearchNames("testproperties");
+		this.initializer.postProcessEnvironment(this.environment, this.application);
+		String a = this.environment.getProperty("a.property");
+		String b = this.environment.getProperty("b.property");
+		assertThat(a).isEqualTo("apple");
+		assertThat(b).isEqualTo("ball");
+	}
+
 	private Condition<ConfigurableEnvironment> matchingPropertySource(final String sourceName) {
 		return new Condition<ConfigurableEnvironment>("environment containing property source " + sourceName) {
 

spring-boot-project/spring-boot/src/test/resources/config/a/testproperties.properties

@@ -0,0 +1 @@
+a.property=apple

spring-boot-project/spring-boot/src/test/resources/config/b/testproperties.properties

@@ -0,0 +1 @@
+b.property=ball