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Initial POC for BootstrapEnvironmentPostProcessor
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‎spring-cloud-context/src/main/java/org/springframework/cloud/bootstrap/BootstrapEnvironmentPostProcessor.java

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/*
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* Copyright 2013-2020 the original author or authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* https://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.springframework.cloud.bootstrap;
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import java.util.ArrayList;
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import java.util.Arrays;
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import java.util.HashMap;
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import java.util.LinkedHashMap;
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import java.util.List;
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import java.util.Map;
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import org.springframework.boot.Banner;
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import org.springframework.boot.SpringApplication;
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import org.springframework.boot.WebApplicationType;
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import org.springframework.boot.builder.SpringApplicationBuilder;
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import org.springframework.boot.env.EnvironmentPostProcessor;
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import org.springframework.boot.env.OriginTrackedMapPropertySource;
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import org.springframework.boot.origin.Origin;
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import org.springframework.boot.origin.OriginLookup;
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import org.springframework.cloud.bootstrap.support.OriginTrackedCompositePropertySource;
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import org.springframework.context.ConfigurableApplicationContext;
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import org.springframework.core.env.CompositePropertySource;
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import org.springframework.core.env.ConfigurableEnvironment;
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import org.springframework.core.env.MapPropertySource;
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import org.springframework.core.env.MutablePropertySources;
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import org.springframework.core.env.PropertySource;
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import org.springframework.core.env.StandardEnvironment;
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import org.springframework.core.env.SystemEnvironmentPropertySource;
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import org.springframework.util.StringUtils;
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public class BootstrapEnvironmentPostProcessor implements EnvironmentPostProcessor {
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/**
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* Property source name for bootstrap.
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*/
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public static final String BOOTSTRAP_PROPERTY_SOURCE_NAME = "bootstrap";
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/**
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* The name of the default properties.
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*/
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public static final String DEFAULT_PROPERTIES = "springCloudDefaultProperties";
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@Override
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public void postProcessEnvironment(ConfigurableEnvironment environment,
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SpringApplication application) {
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if (!environment.getProperty("spring.cloud.bootstrap.enabled", Boolean.class,
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true)) {
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return;
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}
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// don't listen to events in a bootstrap context
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if (environment.getPropertySources().contains(BOOTSTRAP_PROPERTY_SOURCE_NAME)) {
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return;
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}
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String configName = environment
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.resolvePlaceholders("${spring.cloud.bootstrap.name:bootstrap}");
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bootstrapServiceContext(environment, application, configName);
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}
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private ConfigurableApplicationContext bootstrapServiceContext(
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ConfigurableEnvironment environment, final SpringApplication application,
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String configName) {
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StandardEnvironment bootstrapEnvironment = new StandardEnvironment();
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MutablePropertySources bootstrapProperties = bootstrapEnvironment
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.getPropertySources();
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// empty bootstrapProperties
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for (PropertySource<?> source : bootstrapProperties) {
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bootstrapProperties.remove(source.getName());
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}
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String configLocation = environment
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.resolvePlaceholders("${spring.cloud.bootstrap.location:}");
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String configAdditionalLocation = environment
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.resolvePlaceholders("${spring.cloud.bootstrap.additional-location:}");
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Map<String, Object> bootstrapMap = new HashMap<>();
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bootstrapMap.put("spring.config.name", configName);
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// if an app (or test) uses spring.main.web-application-type=reactive, bootstrap
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// will fail // force the environment to use none, because if though it is set
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// below in the builder the environment overrides it
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bootstrapMap.put("spring.main.web-application-type", "none");
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if (StringUtils.hasText(configLocation)) {
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bootstrapMap.put("spring.config.location", configLocation);
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}
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if (StringUtils.hasText(configAdditionalLocation)) {
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bootstrapMap.put("spring.config.additional-location",
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configAdditionalLocation);
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}
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bootstrapProperties.addFirst(
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new MapPropertySource(BOOTSTRAP_PROPERTY_SOURCE_NAME, bootstrapMap));
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for (PropertySource<?> source : environment.getPropertySources()) {
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if (source instanceof PropertySource.StubPropertySource) {
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continue;
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}
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bootstrapProperties.addLast(source);
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}
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// TODO: is it possible or sensible to share a ResourceLoader?
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SpringApplicationBuilder builder = new SpringApplicationBuilder()
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.profiles(environment.getActiveProfiles()).bannerMode(Banner.Mode.OFF)
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.environment(bootstrapEnvironment)
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// Don't use the default properties in this builder
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.registerShutdownHook(false).logStartupInfo(false)
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.web(WebApplicationType.NONE);
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final SpringApplication builderApplication = builder.application();
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if (builderApplication.getMainApplicationClass() == null) {
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// gh_425:
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// SpringApplication cannot deduce the MainApplicationClass here
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// if it is booted from SpringBootServletInitializer due to the
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// absense of the "main" method in stackTraces.
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// But luckily this method's second parameter "application" here
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// carries the real MainApplicationClass which has been explicitly
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// set by SpringBootServletInitializer itself already.
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builder.main(application.getMainApplicationClass());
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}
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if (environment.getPropertySources().contains("refreshArgs")) {
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// If we are doing a context refresh, really we only want to refresh the
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// Environment, and there are some toxic listeners (like the
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// LoggingApplicationListener) that affect global static state, so we need a
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// way to switch those off.
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// builderApplication
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// .setListeners(filterListeners(builderApplication.getListeners()));
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}
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builder.sources(BootstrapImportSelectorConfiguration.class);
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final ConfigurableApplicationContext context = builder.run();
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// gh-214 using spring.application.name=bootstrap to set the context id via
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// `ContextIdApplicationContextInitializer` prevents apps from getting the actual
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// spring.application.name
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// during the bootstrap phase.
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context.setId("bootstrap");
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// Make the bootstrap context a parent of the app context
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// addAncestorInitializer(application, context);
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// It only has properties in it now that we don't want in the parent so remove
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// it (and it will be added back later)
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bootstrapProperties.remove(BOOTSTRAP_PROPERTY_SOURCE_NAME);
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mergeDefaultProperties(environment.getPropertySources(), bootstrapProperties);
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return context;
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}
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private void mergeDefaultProperties(MutablePropertySources environment,
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MutablePropertySources bootstrap) {
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String name = DEFAULT_PROPERTIES;
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if (bootstrap.contains(name)) {
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PropertySource<?> source = bootstrap.get(name);
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if (!environment.contains(name)) {
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environment.addLast(source);
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}
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else {
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PropertySource<?> target = environment.get(name);
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if (target instanceof MapPropertySource && target != source
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&& source instanceof MapPropertySource) {
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Map<String, Object> targetMap = ((MapPropertySource) target)
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.getSource();
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Map<String, Object> map = ((MapPropertySource) source).getSource();
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for (String key : map.keySet()) {
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if (!target.containsProperty(key)) {
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targetMap.put(key, map.get(key));
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}
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}
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}
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}
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}
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mergeAdditionalPropertySources(environment, bootstrap);
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}
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private void mergeAdditionalPropertySources(MutablePropertySources environment,
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MutablePropertySources bootstrap) {
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PropertySource<?> defaultProperties = environment.get(DEFAULT_PROPERTIES);
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ExtendedDefaultPropertySource result = defaultProperties instanceof ExtendedDefaultPropertySource
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? (ExtendedDefaultPropertySource) defaultProperties
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: new ExtendedDefaultPropertySource(DEFAULT_PROPERTIES,
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defaultProperties);
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for (PropertySource<?> source : bootstrap) {
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if (!environment.contains(source.getName())) {
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result.add(source);
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}
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}
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for (String name : result.getPropertySourceNames()) {
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bootstrap.remove(name);
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}
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addOrReplace(environment, result);
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addOrReplace(bootstrap, result);
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}
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private void addOrReplace(MutablePropertySources environment,
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PropertySource<?> result) {
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if (environment.contains(result.getName())) {
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environment.replace(result.getName(), result);
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}
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else {
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environment.addLast(result);
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}
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}
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private static class ExtendedDefaultPropertySource
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extends SystemEnvironmentPropertySource implements OriginLookup<String> {
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private final OriginTrackedCompositePropertySource sources;
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private final List<String> names = new ArrayList<>();
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ExtendedDefaultPropertySource(String name, PropertySource<?> propertySource) {
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super(name, findMap(propertySource));
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this.sources = new OriginTrackedCompositePropertySource(name);
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}
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@SuppressWarnings("unchecked")
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private static Map<String, Object> findMap(PropertySource<?> propertySource) {
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if (propertySource instanceof MapPropertySource) {
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return (Map<String, Object>) propertySource.getSource();
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}
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return new LinkedHashMap<String, Object>();
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}
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public CompositePropertySource getPropertySources() {
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return this.sources;
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}
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public List<String> getPropertySourceNames() {
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return this.names;
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}
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public void add(PropertySource<?> source) {
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// Only add map property sources added by boot, see gh-476
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if (source instanceof OriginTrackedMapPropertySource
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&& !this.names.contains(source.getName())) {
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this.sources.addPropertySource(source);
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this.names.add(source.getName());
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}
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}
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@Override
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public Object getProperty(String name) {
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if (this.sources.containsProperty(name)) {
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return this.sources.getProperty(name);
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}
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return super.getProperty(name);
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}
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@Override
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public boolean containsProperty(String name) {
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if (this.sources.containsProperty(name)) {
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return true;
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}
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return super.containsProperty(name);
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}
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@Override
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public String[] getPropertyNames() {
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List<String> names = new ArrayList<>();
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names.addAll(Arrays.asList(this.sources.getPropertyNames()));
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names.addAll(Arrays.asList(super.getPropertyNames()));
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return names.toArray(new String[0]);
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}
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@Override
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public Origin getOrigin(String name) {
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return this.sources.getOrigin(name);
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}
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}
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}

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

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@@ -7,7 +7,6 @@ org.springframework.cloud.autoconfigure.RefreshEndpointAutoConfiguration,\
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org.springframework.cloud.autoconfigure.WritableEnvironmentEndpointAutoConfiguration
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# Application Listeners
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org.springframework.context.ApplicationListener=\
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org.springframework.cloud.bootstrap.BootstrapApplicationListener,\
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org.springframework.cloud.bootstrap.LoggingSystemShutdownListener,\
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org.springframework.cloud.context.restart.RestartListener
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# Bootstrap components
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org.springframework.cloud.bootstrap.encrypt.EncryptionBootstrapConfiguration,\
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org.springframework.cloud.autoconfigure.ConfigurationPropertiesRebinderAutoConfiguration,\
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org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration
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# Environment post processors
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org.springframework.boot.env.EnvironmentPostProcessor=\
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org.springframework.cloud.bootstrap.BootstrapEnvironmentPostProcessor

‎spring-cloud-context/src/test/java/org/springframework/cloud/bootstrap/BootstrapEnvironmentPostProcessorTests.java

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/*
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* Copyright 2013-2019 the original author or authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* https://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.springframework.cloud.bootstrap;
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import org.junit.Test;
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import org.junit.runner.RunWith;
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import org.springframework.beans.BeansException;
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import org.springframework.beans.factory.NoSuchBeanDefinitionException;
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import org.springframework.beans.factory.annotation.Autowired;
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import org.springframework.boot.SpringBootConfiguration;
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import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
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import org.springframework.boot.test.context.SpringBootTest;
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import org.springframework.context.ApplicationContext;
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import org.springframework.context.ConfigurableApplicationContext;
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import org.springframework.core.env.ConfigurableEnvironment;
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import org.springframework.test.context.junit4.SpringRunner;
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import static org.assertj.core.api.Assertions.assertThat;
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import static org.assertj.core.api.Assertions.fail;
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@RunWith(SpringRunner.class)
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@SpringBootTest
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public class BootstrapEnvironmentPostProcessorTests {
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@Autowired
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private ConfigurableEnvironment env;
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@Autowired
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private ConfigurableApplicationContext context;
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@Test
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public void contextLoads() {
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// from bootstrap.properties
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assertThat(env.getProperty("test.property")).isEqualTo("from bootstrap.properties");
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try {
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assertThat(context.getBean("foo-during-bootstrap"));
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fail("bean created in bootstrap found");
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}
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catch (NoSuchBeanDefinitionException e) {
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// shouldn't exist
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}
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}
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@EnableAutoConfiguration
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@SpringBootConfiguration
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protected static class TestConfig {
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}
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}

‎spring-cloud-context/src/test/resources/bootstrap.properties

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spring.main.sources:org.springframework.cloud.bootstrap.config.BootstrapConfigurationTests.PropertySourceConfiguration,org.springframework.cloud.bootstrap.config.BootstrapConfigurationTests.CompositePropertySourceConfiguration
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info.name:child
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info.desc: defaultPropertiesInfoDesc
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test.property: from bootstrap.properties

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