Add application listener to locate property sources during bootstrap

Also adds support for activating profiles using spring.profiles.active from bootstrap property source listeners.

Allow profiles to be passed from bootstrap context to main application context

Author: ryanjbaxter

docs/src/main/asciidoc/_configprops.adoc

@@ -4,6 +4,7 @@
 |spring.cloud.compatibility-verifier.compatible-boot-versions |  | Default accepted versions for the Spring Boot dependency. You can set {@code x} for the patch version if you don't want to specify a concrete value. Example: {@code 3.4.x}
 |spring.cloud.compatibility-verifier.enabled | `+++false+++` | Enables creation of Spring Cloud compatibility verification.
 |spring.cloud.config.allow-override | `+++true+++` | Flag to indicate that {@link #isOverrideSystemProperties() systemPropertiesOverride} can be used. Set to false to prevent users from changing the default accidentally. Default true.
+|spring.cloud.config.initialize-on-context-refresh | `+++false+++` | Flag to initialize bootstrap configuration on context refresh event. Default false.
 |spring.cloud.config.override-none | `+++false+++` | Flag to indicate that when {@link #setAllowOverride(boolean) allowOverride} is true, external properties should take lowest priority and should not override any existing property sources (including local config files). Default false.
 |spring.cloud.config.override-system-properties | `+++true+++` | Flag to indicate that the external properties should override system properties. Default true.
 |spring.cloud.decrypt-environment-post-processor.enabled | `+++true+++` | Enable the DecryptEnvironmentPostProcessor.

docs/src/main/asciidoc/spring-cloud-commons.adoc

@@ -54,6 +54,10 @@ The additional property sources are:
 An example would be properties from the Spring Cloud Config Server.
 See "`<<customizing-bootstrap-property-sources>>`" for how to customize the contents of this property source.
 
+NOTE:  Prior to Spring Cloud 2021.0.7 `PropertySourceLocators` (including the ones for Spring Cloud Config) were run during
+the main application context and not in the Bootstrap context.  You can force `PropertySourceLocators` to be run during the
+Bootstrap context by setting `spring.cloud.config.initialize-on-context-refresh=true` in `bootstrap.[properties | yaml]`.
+
 * "`applicationConfig: [classpath:bootstrap.yml]`" (and related files if Spring profiles are active): If you have a `bootstrap.yml` (or `.properties`), those properties are used to configure the bootstrap context.
 Then they get added to the child context when its parent is set.
 They have lower precedence than the `application.yml` (or `.properties`) and any other property sources that are added to the child as a normal part of the process of creating a Spring Boot application.
@@ -146,6 +150,12 @@ org.springframework.cloud.bootstrap.BootstrapConfiguration=sample.custom.CustomP
 ----
 ====
 
+As of Spring Cloud 2021.0.7, Spring Cloud will now call `PropertySourceLocators` twice.  The first fetch
+will retrieve any property sources without any profiles.  These property sources will have the opportunity to
+activate profiles using `spring.profiles.active`.  After the main application context starts `PropertySourceLocators`
+will be called a second time, this time with any active profiles allowing `PropertySourceLocators` to locate
+any additional `PropertySources` with profiles.
+
 === Logging Configuration
 
 If you use Spring Boot to configure log settings, you should place this configuration in `bootstrap.[yml | properties]` if you would like it to apply to all events.

spring-cloud-context/src/main/java/org/springframework/cloud/bootstrap/BootstrapApplicationListener.java

@@ -294,6 +294,13 @@ private void apply(ConfigurableApplicationContext context, SpringApplication app
 		target.addAll(getOrderedBeansOfType(context, ApplicationContextInitializer.class));
 		application.setInitializers(target);
 		addBootstrapDecryptInitializer(application);
+
+		// Get the active profiles from the bootstrap context and set them in main
+		// application
+		// environment. This allows any profiles activated during bootstrap to be
+		// activated when
+		// config data runs in the main application context.
+		environment.setActiveProfiles(context.getEnvironment().getActiveProfiles());
 	}
 
 	@SuppressWarnings("unchecked")

spring-cloud-context/src/main/java/org/springframework/cloud/bootstrap/config/PropertySourceBootstrapConfiguration.java

@@ -17,18 +17,20 @@
 package org.springframework.cloud.bootstrap.config;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.TreeSet;
+import java.util.stream.Collectors;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.boot.context.config.ConfigFileApplicationListener;
+import org.springframework.boot.context.config.Profiles;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.boot.context.properties.bind.Bindable;
 import org.springframework.boot.context.properties.bind.Binder;
@@ -39,8 +41,10 @@
 import org.springframework.cloud.context.environment.EnvironmentChangeEvent;
 import org.springframework.cloud.logging.LoggingRebinder;
 import org.springframework.context.ApplicationContextInitializer;
+import org.springframework.context.ApplicationListener;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.context.event.ContextRefreshedEvent;
 import org.springframework.core.Ordered;
 import org.springframework.core.annotation.AnnotationAwareOrderComparator;
 import org.springframework.core.env.AbstractEnvironment;
@@ -52,6 +56,7 @@
 import org.springframework.core.env.PropertySource;
 import org.springframework.util.StringUtils;
 
+import static org.springframework.cloud.bootstrap.encrypt.AbstractEnvironmentDecrypt.DECRYPTED_PROPERTY_SOURCE_NAME;
 import static org.springframework.core.env.StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME;
 
 /**
@@ -60,8 +65,8 @@
  */
 @Configuration(proxyBeanMethods = false)
 @EnableConfigurationProperties(PropertySourceBootstrapProperties.class)
-public class PropertySourceBootstrapConfiguration
-		implements ApplicationContextInitializer<ConfigurableApplicationContext>, Ordered {
+public class PropertySourceBootstrapConfiguration implements ApplicationListener<ContextRefreshedEvent>,
+		ApplicationContextInitializer<ConfigurableApplicationContext>, Ordered {
 
 	/**
 	 * Bootstrap property source name.
@@ -76,6 +81,9 @@ public class PropertySourceBootstrapConfiguration
 	@Autowired(required = false)
 	private List<PropertySourceLocator> propertySourceLocators = new ArrayList<>();
 
+	@Autowired
+	private PropertySourceBootstrapProperties bootstrapProperties;
+
 	@Override
 	public int getOrder() {
 		return this.order;
@@ -85,8 +93,25 @@ public void setPropertySourceLocators(Collection<PropertySourceLocator> property
 		this.propertySourceLocators = new ArrayList<>(propertySourceLocators);
 	}
 
+	/*
+	 * The ApplicationListener is called when the main application context is initialized.
+	 * This will be called after the ApplicationListener ContextRefreshedEvent is fired
+	 * during the bootstrap phase. This method is also what added PropertySources prior to
+	 * Spring Cloud 2021.0.7, this is why it will be called when
+	 * spring.cloud.config.initialize-on-context-refresh is false. When
+	 * spring.cloud.config.initialize-on-context-refresh is true this method provides a
+	 * "second fetch" of configuration data to fetch any additional configuration data
+	 * from profiles that have been activated.
+	 */
 	@Override
 	public void initialize(ConfigurableApplicationContext applicationContext) {
+		if (!bootstrapProperties.isInitializeOnContextRefresh() || !applicationContext.getEnvironment()
+				.getPropertySources().contains(BootstrapApplicationListener.BOOTSTRAP_PROPERTY_SOURCE_NAME)) {
+			doInitialize(applicationContext);
+		}
+	}
+
+	private void doInitialize(ConfigurableApplicationContext applicationContext) {
 		List<PropertySource<?>> composite = new ArrayList<>();
 		AnnotationAwareOrderComparator.sort(this.propertySourceLocators);
 		boolean empty = true;
@@ -122,7 +147,7 @@ public void initialize(ConfigurableApplicationContext applicationContext) {
 			insertPropertySources(propertySources, composite);
 			reinitializeLoggingSystem(environment, logConfig, logFile);
 			setLogLevels(applicationContext, environment);
-			handleIncludedProfiles(environment);
+			handleProfiles(environment);
 		}
 	}
 
@@ -172,7 +197,12 @@ private void insertPropertySources(MutablePropertySources propertySources, List<
 		if (!remoteProperties.isAllowOverride()
 				|| (!remoteProperties.isOverrideNone() && remoteProperties.isOverrideSystemProperties())) {
 			for (PropertySource<?> p : reversedComposite) {
-				propertySources.addFirst(p);
+				if (propertySources.contains(DECRYPTED_PROPERTY_SOURCE_NAME)) {
+					propertySources.addAfter(DECRYPTED_PROPERTY_SOURCE_NAME, p);
+				}
+				else {
+					propertySources.addFirst(p);
+				}
 			}
 			return;
 		}
@@ -210,43 +240,98 @@ private Environment environment(MutablePropertySources incoming) {
 		return environment;
 	}
 
-	private void handleIncludedProfiles(ConfigurableEnvironment environment) {
+	private void handleProfiles(ConfigurableEnvironment environment) {
+		if (bootstrapProperties.isInitializeOnContextRefresh() && !environment.getPropertySources()
+				.contains(BootstrapApplicationListener.BOOTSTRAP_PROPERTY_SOURCE_NAME)) {
+			// In the case that spring.cloud.config.initialize-on-context-refresh is true
+			// this method will
+			// be called during the bootstrap phase and the main application startup. We
+			// only manipulate the environment profiles in the bootstrap phase as we are
+			// fetching
+			// any additional profile specific configuration when this method would be
+			// called during the
+			// main application startup, and it is not valid to activate profiles in
+			// profile specific
+			// configuration properties, so we should not run this method then.
+			return;
+		}
 		Set<String> includeProfiles = new TreeSet<>();
+		List<String> activeProfiles = new ArrayList<>();
+
 		for (PropertySource<?> propertySource : environment.getPropertySources()) {
-			addIncludedProfilesTo(includeProfiles, propertySource);
+			addIncludedProfilesTo(includeProfiles, propertySource, environment);
+			addActiveProfilesTo(activeProfiles, propertySource, environment);
 		}
-		List<String> activeProfiles = new ArrayList<>();
-		Collections.addAll(activeProfiles, environment.getActiveProfiles());
 
 		// If it's already accepted we assume the order was set intentionally
 		includeProfiles.removeAll(activeProfiles);
-		if (includeProfiles.isEmpty()) {
-			return;
-		}
 		// Prepend each added profile (last wins in a property key clash)
 		for (String profile : includeProfiles) {
 			activeProfiles.add(0, profile);
 		}
+		List<String> activeProfilesFromEnvironment = Arrays.stream(environment.getActiveProfiles())
+				.collect(Collectors.toList());
+		if (!activeProfiles.containsAll(activeProfilesFromEnvironment)) {
+			activeProfiles.addAll(activeProfilesFromEnvironment);
+
+		}
 		environment.setActiveProfiles(activeProfiles.toArray(new String[activeProfiles.size()]));
 	}
 
-	private Set<String> addIncludedProfilesTo(Set<String> profiles, PropertySource<?> propertySource) {
+	private Set<String> addIncludedProfilesTo(Set<String> profiles, PropertySource<?> propertySource,
+			ConfigurableEnvironment environment) {
+		return addProfilesTo(profiles, propertySource, Profiles.INCLUDE_PROFILES_PROPERTY_NAME, environment);
+	}
+
+	private List<String> addActiveProfilesTo(List<String> profiles, PropertySource<?> propertySource,
+			ConfigurableEnvironment environment) {
+		return addProfilesTo(profiles, propertySource, AbstractEnvironment.ACTIVE_PROFILES_PROPERTY_NAME, environment);
+	}
+
+	private <T extends Collection<String>> T addProfilesTo(T profiles, PropertySource<?> propertySource,
+			String property, ConfigurableEnvironment environment) {
 		if (propertySource instanceof CompositePropertySource) {
 			for (PropertySource<?> nestedPropertySource : ((CompositePropertySource) propertySource)
 					.getPropertySources()) {
-				addIncludedProfilesTo(profiles, nestedPropertySource);
+				addProfilesTo(profiles, nestedPropertySource, property, environment);
 			}
 		}
 		else {
-			Collections.addAll(profiles, getProfilesForValue(
-					propertySource.getProperty(ConfigFileApplicationListener.INCLUDE_PROFILES_PROPERTY)));
+			Collections.addAll(profiles, getProfilesForValue(propertySource.getProperty(property), environment));
 		}
 		return profiles;
 	}
 
-	private String[] getProfilesForValue(Object property) {
+	private String[] getProfilesForValue(Object property, ConfigurableEnvironment environment) {
 		final String value = (property == null ? null : property.toString());
-		return property == null ? new String[0] : StringUtils.tokenizeToStringArray(value, ",");
+		return property == null ? new String[0] : resolvePlaceholdersInProfiles(value, environment);
+	}
+
+	private String[] resolvePlaceholdersInProfiles(String profiles, ConfigurableEnvironment environment) {
+		return Arrays.stream(StringUtils.tokenizeToStringArray(profiles, ",")).map(s -> {
+			if (s.startsWith("${") && s.endsWith("}")) {
+				return environment.resolvePlaceholders(s);
+			}
+			else {
+				return s;
+			}
+		}).toArray(String[]::new);
+	}
+
+	/*
+	 * The ConextRefreshedEvent gets called at the end of the boostrap phase after config
+	 * data is loaded during bootstrap. This will run and do an "initial fetch" of
+	 * configuration data during bootstrap but before the main applicaiton context starts.
+	 */
+	@Override
+	public void onApplicationEvent(ContextRefreshedEvent event) {
+		if (bootstrapProperties.isInitializeOnContextRefresh()
+				&& event.getApplicationContext() instanceof ConfigurableApplicationContext) {
+			if (((ConfigurableApplicationContext) event.getApplicationContext()).getEnvironment().getPropertySources()
+					.contains(BootstrapApplicationListener.BOOTSTRAP_PROPERTY_SOURCE_NAME)) {
+				doInitialize((ConfigurableApplicationContext) event.getApplicationContext());
+			}
+		}
 	}
 
 }

spring-cloud-context/src/main/java/org/springframework/cloud/bootstrap/config/PropertySourceBootstrapProperties.java

@@ -46,6 +46,19 @@ public class PropertySourceBootstrapProperties {
 	 */
 	private boolean overrideNone = false;
 
+	/**
+	 * Flag to initialize bootstrap configuration on context refresh event. Default false.
+	 */
+	private boolean initializeOnContextRefresh = false;
+
+	public boolean isInitializeOnContextRefresh() {
+		return initializeOnContextRefresh;
+	}
+
+	public void setInitializeOnContextRefresh(boolean initializeOnContextRefresh) {
+		this.initializeOnContextRefresh = initializeOnContextRefresh;
+	}
+
 	public boolean isOverrideNone() {
 		return this.overrideNone;
 	}

spring-cloud-context/src/main/resources/META-INF/spring.factories

@@ -23,4 +23,4 @@ org.springframework.cloud.bootstrap.TextEncryptorConfigBootstrapper
 # Environment Post Processors
 org.springframework.boot.env.EnvironmentPostProcessor=\
 org.springframework.cloud.bootstrap.encrypt.DecryptEnvironmentPostProcessor,\
-org.springframework.cloud.util.random.CachedRandomPropertySourceEnvironmentPostProcessor
+org.springframework.cloud.util.random.CachedRandomPropertySourceEnvironmentPostProcessor