https://spring.io/projects/spring-boot: Spring Boot (Pivotal Software, Inc.) 
/*
 * 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.
 * 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.context.config;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;

import org.apache.commons.logging.Log;

import org.springframework.boot.BootstrapRegistry.InstanceSupplier;
import org.springframework.boot.ConfigurableBootstrapContext;
import org.springframework.boot.DefaultPropertiesPropertySource;
import org.springframework.boot.context.config.ConfigDataEnvironmentContributors.BinderOption;
import org.springframework.boot.context.properties.bind.BindException;
import org.springframework.boot.context.properties.bind.Bindable;
import org.springframework.boot.context.properties.bind.Binder;
import org.springframework.boot.context.properties.bind.PlaceholdersResolver;
import org.springframework.boot.context.properties.source.ConfigurationPropertyName;
import org.springframework.boot.context.properties.source.ConfigurationPropertySource;
import org.springframework.boot.logging.DeferredLogFactory;
import org.springframework.core.env.ConfigurableEnvironment;
import org.springframework.core.env.Environment;
import org.springframework.core.env.MutablePropertySources;
import org.springframework.core.env.PropertySource;
import org.springframework.core.io.ResourceLoader;
import org.springframework.core.log.LogMessage;
import org.springframework.util.StringUtils;


Wrapper around a ConfigurableEnvironment that can be used to import and apply ConfigData. Configures the initial set of ConfigDataEnvironmentContributors by wrapping property sources from the Spring Environment and adding the initial set of locations. 
 The initial locations can be influenced via the LOCATION_PROPERTY, "spring.config.additional-location" and "spring.config.import" properties. If no explicit properties are set, the DEFAULT_SEARCH_LOCATIONS will be used. 
Author:Phillip Webb, Madhura Bhave
/**
 * Wrapper around a {@link ConfigurableEnvironment} that can be used to import and apply
 * {@link ConfigData}. Configures the initial set of
 * {@link ConfigDataEnvironmentContributors} by wrapping property sources from the Spring
 * {@link Environment} and adding the initial set of locations.
 * <p>
 * The initial locations can be influenced via the {@link #LOCATION_PROPERTY},
 * {@value #ADDITIONAL_LOCATION_PROPERTY} and {@value #IMPORT_PROPERTY} properties. If no
 * explicit properties are set, the {@link #DEFAULT_SEARCH_LOCATIONS} will be used.
 *
 * @author Phillip Webb
 * @author Madhura Bhave
 */
class ConfigDataEnvironment {

	
Property used override the imported locations.

/**
	 * Property used override the imported locations.
	 */
	static final String LOCATION_PROPERTY = "spring.config.location";

	
Property used to provide additional locations to import.

/**
	 * Property used to provide additional locations to import.
	 */
	static final String ADDITIONAL_LOCATION_PROPERTY = "spring.config.additional-location";

	
Property used to provide additional locations to import.

/**
	 * Property used to provide additional locations to import.
	 */
	static final String IMPORT_PROPERTY = "spring.config.import";

	
Property used to determine what action to take when a ConfigDataNotFoundAction is thrown. 
See Also:
/**
	 * Property used to determine what action to take when a
	 * {@code ConfigDataNotFoundAction} is thrown.
	 * @see ConfigDataNotFoundAction
	 */
	static final String ON_NOT_FOUND_PROPERTY = "spring.config.on-not-found";

	
Default search locations used if not LOCATION_PROPERTY is found. 
/**
	 * Default search locations used if not {@link #LOCATION_PROPERTY} is found.
	 */
	static final ConfigDataLocation[] DEFAULT_SEARCH_LOCATIONS;
	static {
		List<ConfigDataLocation> locations = new ArrayList<>();
		locations.add(ConfigDataLocation.of("optional:classpath:/"));
		locations.add(ConfigDataLocation.of("optional:classpath:/config/"));
		locations.add(ConfigDataLocation.of("optional:file:./"));
		locations.add(ConfigDataLocation.of("optional:file:./config/"));
		locations.add(ConfigDataLocation.of("optional:file:./config/*/"));
		DEFAULT_SEARCH_LOCATIONS = locations.toArray(new ConfigDataLocation[0]);
	};

	private static final ConfigDataLocation[] EMPTY_LOCATIONS = new ConfigDataLocation[0];

	private static final ConfigurationPropertyName INCLUDE_PROFILES = ConfigurationPropertyName
			.of(Profiles.INCLUDE_PROFILES_PROPERTY_NAME);

	private static final Bindable<ConfigDataLocation[]> CONFIG_DATA_LOCATION_ARRAY = Bindable
			.of(ConfigDataLocation[].class);

	private static final Bindable<List<String>> STRING_LIST = Bindable.listOf(String.class);

	private final DeferredLogFactory logFactory;

	private final Log logger;

	private final ConfigDataNotFoundAction notFoundAction;

	private final ConfigurableBootstrapContext bootstrapContext;

	private final ConfigurableEnvironment environment;

	private final ConfigDataLocationResolvers resolvers;

	private final Collection<String> additionalProfiles;

	private final ConfigDataLoaders loaders;

	private final ConfigDataEnvironmentContributors contributors;

	
Create a new ConfigDataEnvironment instance. 
Params:
  • logFactory – the deferred log factory
  • bootstrapContext – the bootstrap context
  • environment – the Spring Environment.
  • resourceLoader – ResourceLoader to load resource locations
  • additionalProfiles – any additional profiles to activate
/**
	 * Create a new {@link ConfigDataEnvironment} instance.
	 * @param logFactory the deferred log factory
	 * @param bootstrapContext the bootstrap context
	 * @param environment the Spring {@link Environment}.
	 * @param resourceLoader {@link ResourceLoader} to load resource locations
	 * @param additionalProfiles any additional profiles to activate
	 */
	ConfigDataEnvironment(DeferredLogFactory logFactory, ConfigurableBootstrapContext bootstrapContext,
			ConfigurableEnvironment environment, ResourceLoader resourceLoader, Collection<String> additionalProfiles) {
		Binder binder = Binder.get(environment);
		UseLegacyConfigProcessingException.throwIfRequested(binder);
		this.logFactory = logFactory;
		this.logger = logFactory.getLog(getClass());
		this.notFoundAction = binder.bind(ON_NOT_FOUND_PROPERTY, ConfigDataNotFoundAction.class)
				.orElse(ConfigDataNotFoundAction.FAIL);
		this.bootstrapContext = bootstrapContext;
		this.environment = environment;
		this.resolvers = createConfigDataLocationResolvers(logFactory, bootstrapContext, binder, resourceLoader);
		this.additionalProfiles = additionalProfiles;
		this.loaders = new ConfigDataLoaders(logFactory, bootstrapContext);
		this.contributors = createContributors(binder);
	}

	protected ConfigDataLocationResolvers createConfigDataLocationResolvers(DeferredLogFactory logFactory,
			ConfigurableBootstrapContext bootstrapContext, Binder binder, ResourceLoader resourceLoader) {
		return new ConfigDataLocationResolvers(logFactory, bootstrapContext, binder, resourceLoader);
	}

	private ConfigDataEnvironmentContributors createContributors(Binder binder) {
		this.logger.trace("Building config data environment contributors");
		MutablePropertySources propertySources = this.environment.getPropertySources();
		List<ConfigDataEnvironmentContributor> contributors = new ArrayList<>(propertySources.size() + 10);
		PropertySource<?> defaultPropertySource = null;
		for (PropertySource<?> propertySource : propertySources) {
			if (DefaultPropertiesPropertySource.hasMatchingName(propertySource)) {
				defaultPropertySource = propertySource;
			}
			else {
				this.logger.trace(LogMessage.format("Creating wrapped config data contributor for '%s'",
						propertySource.getName()));
				contributors.add(ConfigDataEnvironmentContributor.ofExisting(propertySource));
			}
		}
		contributors.addAll(getInitialImportContributors(binder));
		if (defaultPropertySource != null) {
			this.logger.trace("Creating wrapped config data contributor for default property source");
			contributors.add(ConfigDataEnvironmentContributor.ofExisting(defaultPropertySource));
		}
		return new ConfigDataEnvironmentContributors(this.logFactory, this.bootstrapContext, contributors);
	}

	ConfigDataEnvironmentContributors getContributors() {
		return this.contributors;
	}

	private List<ConfigDataEnvironmentContributor> getInitialImportContributors(Binder binder) {
		List<ConfigDataEnvironmentContributor> initialContributors = new ArrayList<>();
		addInitialImportContributors(initialContributors, bindLocations(binder, IMPORT_PROPERTY, EMPTY_LOCATIONS));
		addInitialImportContributors(initialContributors,
				bindLocations(binder, ADDITIONAL_LOCATION_PROPERTY, EMPTY_LOCATIONS));
		addInitialImportContributors(initialContributors,
				bindLocations(binder, LOCATION_PROPERTY, DEFAULT_SEARCH_LOCATIONS));
		return initialContributors;
	}

	private ConfigDataLocation[] bindLocations(Binder binder, String propertyName, ConfigDataLocation[] other) {
		return binder.bind(propertyName, CONFIG_DATA_LOCATION_ARRAY).orElse(other);
	}

	private void addInitialImportContributors(List<ConfigDataEnvironmentContributor> initialContributors,
			ConfigDataLocation[] locations) {
		for (int i = locations.length - 1; i >= 0; i--) {
			initialContributors.add(createInitialImportContributor(locations[i]));
		}
	}

	private ConfigDataEnvironmentContributor createInitialImportContributor(ConfigDataLocation location) {
		this.logger.trace(LogMessage.format("Adding initial config data import from location '%s'", location));
		return ConfigDataEnvironmentContributor.ofInitialImport(location);
	}

	
Process all contributions and apply any newly imported property sources to the Environment. 
/**
	 * Process all contributions and apply any newly imported property sources to the
	 * {@link Environment}.
	 */
	void processAndApply() {
		ConfigDataImporter importer = new ConfigDataImporter(this.logFactory, this.notFoundAction, this.resolvers,
				this.loaders);
		this.bootstrapContext.register(Binder.class, InstanceSupplier
				.from(() -> this.contributors.getBinder(null, BinderOption.FAIL_ON_BIND_TO_INACTIVE_SOURCE)));
		ConfigDataEnvironmentContributors contributors = processInitial(this.contributors, importer);
		Binder initialBinder = contributors.getBinder(null, BinderOption.FAIL_ON_BIND_TO_INACTIVE_SOURCE);
		this.bootstrapContext.register(Binder.class, InstanceSupplier.of(initialBinder));
		ConfigDataActivationContext activationContext = createActivationContext(initialBinder);
		contributors = processWithoutProfiles(contributors, importer, activationContext);
		activationContext = withProfiles(contributors, activationContext);
		contributors = processWithProfiles(contributors, importer, activationContext);
		applyToEnvironment(contributors, activationContext);
	}

	private ConfigDataEnvironmentContributors processInitial(ConfigDataEnvironmentContributors contributors,
			ConfigDataImporter importer) {
		this.logger.trace("Processing initial config data environment contributors without activation context");
		return contributors.withProcessedImports(importer, null);
	}

	private ConfigDataActivationContext createActivationContext(Binder initialBinder) {
		this.logger.trace("Creating config data activation context from initial contributions");
		try {
			return new ConfigDataActivationContext(this.environment, initialBinder);
		}
		catch (BindException ex) {
			if (ex.getCause() instanceof InactiveConfigDataAccessException) {
				throw (InactiveConfigDataAccessException) ex.getCause();
			}
			throw ex;
		}
	}

	private ConfigDataEnvironmentContributors processWithoutProfiles(ConfigDataEnvironmentContributors contributors,
			ConfigDataImporter importer, ConfigDataActivationContext activationContext) {
		this.logger.trace("Processing config data environment contributors with initial activation context");
		return contributors.withProcessedImports(importer, activationContext);
	}

	private ConfigDataActivationContext withProfiles(ConfigDataEnvironmentContributors contributors,
			ConfigDataActivationContext activationContext) {
		this.logger.trace("Deducing profiles from current config data environment contributors");
		Binder binder = contributors.getBinder(activationContext, BinderOption.FAIL_ON_BIND_TO_INACTIVE_SOURCE);
		try {
			Set<String> additionalProfiles = new LinkedHashSet<>(this.additionalProfiles);
			additionalProfiles.addAll(getIncludedProfiles(contributors, activationContext));
			Profiles profiles = new Profiles(this.environment, binder, additionalProfiles);
			return activationContext.withProfiles(profiles);
		}
		catch (BindException ex) {
			if (ex.getCause() instanceof InactiveConfigDataAccessException) {
				throw (InactiveConfigDataAccessException) ex.getCause();
			}
			throw ex;
		}
	}

	private Collection<? extends String> getIncludedProfiles(ConfigDataEnvironmentContributors contributors,
			ConfigDataActivationContext activationContext) {
		PlaceholdersResolver placeholdersResolver = new ConfigDataEnvironmentContributorPlaceholdersResolver(
				contributors, activationContext, true);
		Set<String> result = new LinkedHashSet<>();
		for (ConfigDataEnvironmentContributor contributor : contributors) {
			ConfigurationPropertySource source = contributor.getConfigurationPropertySource();
			if (source == null) {
				continue;
			}
			Binder binder = new Binder(Collections.singleton(source), placeholdersResolver);
			binder.bind(INCLUDE_PROFILES, STRING_LIST).ifBound((includes) -> {
				if (!contributor.isActive(activationContext)) {
					InactiveConfigDataAccessException.throwIfPropertyFound(contributor, INCLUDE_PROFILES);
				}
				result.addAll(includes);
			});
		}
		return result;
	}

	private ConfigDataEnvironmentContributors processWithProfiles(ConfigDataEnvironmentContributors contributors,
			ConfigDataImporter importer, ConfigDataActivationContext activationContext) {
		this.logger.trace("Processing config data environment contributors with profile activation context");
		return contributors.withProcessedImports(importer, activationContext);
	}

	private void applyToEnvironment(ConfigDataEnvironmentContributors contributors,
			ConfigDataActivationContext activationContext) {
		checkForInvalidProperties(contributors);
		checkMandatoryLocations(contributors, activationContext);
		MutablePropertySources propertySources = this.environment.getPropertySources();
		this.logger.trace("Applying config data environment contributions");
		for (ConfigDataEnvironmentContributor contributor : contributors) {
			if (contributor.getKind() == ConfigDataEnvironmentContributor.Kind.BOUND_IMPORT
					&& contributor.getPropertySource() != null) {
				if (!contributor.isActive(activationContext)) {
					this.logger.trace(LogMessage.format("Skipping inactive property source '%s'",
							contributor.getPropertySource().getName()));
				}
				else {
					this.logger.trace(LogMessage.format("Adding imported property source '%s'",
							contributor.getPropertySource().getName()));
					propertySources.addLast(contributor.getPropertySource());
				}
			}
		}
		DefaultPropertiesPropertySource.moveToEnd(propertySources);
		Profiles profiles = activationContext.getProfiles();
		this.logger.trace(LogMessage.format("Setting default profiles: %s", profiles.getDefault()));
		this.environment.setDefaultProfiles(StringUtils.toStringArray(profiles.getDefault()));
		this.logger.trace(LogMessage.format("Setting active profiles: %s", profiles.getActive()));
		this.environment.setActiveProfiles(StringUtils.toStringArray(profiles.getActive()));
	}

	private void checkForInvalidProperties(ConfigDataEnvironmentContributors contributors) {
		for (ConfigDataEnvironmentContributor contributor : contributors) {
			InvalidConfigDataPropertyException.throwOrWarn(this.logger, contributor);
		}
	}

	private void checkMandatoryLocations(ConfigDataEnvironmentContributors contributors,
			ConfigDataActivationContext activationContext) {
		Set<ConfigDataLocation> mandatoryLocations = new LinkedHashSet<>();
		for (ConfigDataEnvironmentContributor contributor : contributors) {
			mandatoryLocations.addAll(getMandatoryImports(contributor));
		}
		for (ConfigDataEnvironmentContributor contributor : contributors) {
			if (contributor.getLocation() != null) {
				mandatoryLocations.remove(contributor.getLocation());
			}
		}
		if (!mandatoryLocations.isEmpty()) {
			for (ConfigDataLocation mandatoryLocation : mandatoryLocations) {
				this.notFoundAction.handle(this.logger, new ConfigDataLocationNotFoundException(mandatoryLocation));
			}
		}
	}

	private Set<ConfigDataLocation> getMandatoryImports(ConfigDataEnvironmentContributor contributor) {
		List<ConfigDataLocation> imports = contributor.getImports();
		Set<ConfigDataLocation> mandatoryLocations = new LinkedHashSet<>(imports.size());
		for (ConfigDataLocation location : imports) {
			if (!location.isOptional()) {
				mandatoryLocations.add(location);
			}
		}
		return mandatoryLocations;
	}

}