Spring Boot常用功能Profile详解
作者:lhf2112
入口
相关逻辑的入口是listener类:ConfigFileApplicationListener,当容器广播器触发ApplicationEnvironmentPreparedEvent事件时,ConfigFileApplicationListener会收到广播器的通知,进而执行onApplicationEnvironmentPreparedEvent方法
入口处代码:
@Override public void onApplicationEvent(ApplicationEvent event) { if (event instanceof ApplicationEnvironmentPreparedEvent) { onApplicationEnvironmentPreparedEvent((ApplicationEnvironmentPreparedEvent) event); } if (event instanceof ApplicationPreparedEvent) { onApplicationPreparedEvent(event); } }
接下来onApplicationEnvironmentPreparedEvent方法会加载容器中的EnvironmentPostProcessor并进行遍历,调用他们的postProcessEnvironment方法,我们可以看一下此时的PostProcessor有哪些:
我们发现ConfigFileApplicationListener本身也是其中一个PostProcessor :)
我们直接进入ConfigFileApplicationListener的postProcessEnvironment方法,它会调用一个addPropertySources方法
protected void addPropertySources(ConfigurableEnvironment environment, ResourceLoader resourceLoader) { RandomValuePropertySource.addToEnvironment(environment); new Loader(environment, resourceLoader).load(); }
随机属性值部分暂且不表,我们看下loader.load方法
public void load() { this.profiles = new LinkedList<>(); this.processedProfiles = new LinkedList<>(); this.activatedProfiles = false; this.loaded = new LinkedHashMap<>(); initializeProfiles(); while (!this.profiles.isEmpty()) { Profile profile = this.profiles.poll(); if (profile != null && !profile.isDefaultProfile()) { addProfileToEnvironment(profile.getName()); } load(profile, this::getPositiveProfileFilter, addToLoaded(MutablePropertySources::addLast, false)); this.processedProfiles.add(profile); } resetEnvironmentProfiles(this.processedProfiles); load(null, this::getNegativeProfileFilter, addToLoaded(MutablePropertySources::addFirst, true)); addLoadedPropertySources(); }
load方法的重点逻辑-initializeProfiles()
private void initializeProfiles() { // The default profile for these purposes is represented as null. We add it // first so that it is processed first and has lowest priority. this.profiles.add(null); Set<Profile> activatedViaProperty = getProfilesActivatedViaProperty(); this.profiles.addAll(getOtherActiveProfiles(activatedViaProperty)); // Any pre-existing active profiles set via property sources (e.g. // System properties) take precedence over those added in config files. addActiveProfiles(activatedViaProperty); if (this.profiles.size() == 1) { // only has null profile for (String defaultProfileName : this.environment.getDefaultProfiles()) { Profile defaultProfile = new Profile(defaultProfileName, true); this.profiles.add(defaultProfile); } } }
add(null) 可以处理application.properties/yml,接下来getProfilesActivatedViaProperty方法会从spring.profiles.active和spring.profiles.include配置中读取激活的profile~(这两者也是相对常用的配置);再接下来会判断profiles大小是否为1,是的话会添加一个default profile,如图所示:
这也解释了为什么spring.profiles.default必须定义在其他属性源(命令行启动参数),因为这时候分散文件属性元还没有被解析到!
回到load方法,如果profiles不为空,就会进行while遍历,对其调用另外一个load方法:
(load-number2方法):
private void load(Profile profile, DocumentFilterFactory filterFactory, DocumentConsumer consumer) { getSearchLocations().forEach((location) -> { boolean isFolder = location.endsWith("/"); Set<String> names = isFolder ? getSearchNames() : NO_SEARCH_NAMES; names.forEach((name) -> load(location, name, profile, filterFactory, consumer)); }); }
我们可以看到还会调用到另一个load方法
(load-number3方法):
private void load(String location, String name, Profile profile, DocumentFilterFactory filterFactory, DocumentConsumer consumer) { if (!StringUtils.hasText(name)) { for (PropertySourceLoader loader : this.propertySourceLoaders) { if (canLoadFileExtension(loader, location)) { load(loader, location, profile, filterFactory.getDocumentFilter(profile), consumer); return; } } } Set<String> processed = new HashSet<>(); for (PropertySourceLoader loader : this.propertySourceLoaders) { for (String fileExtension : loader.getFileExtensions()) { if (processed.add(fileExtension)) { loadForFileExtension(loader, location + name, "." + fileExtension, profile, filterFactory, consumer); } } } }
这里的propertySourceLoaders包括:
是不是很熟悉?这就是properties和yaml分别对应的PropertySourceLoader~
下面代码会调用loadForFileExtension方法,而这个方法又会调用新的load方法(😓):
(load-number4方法):
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); } 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); } 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); } return; } 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); } } } catch (Exception ex) { throw new IllegalStateException("Failed to load property " + "source from location '" + location + "'", ex); } }
这个方法会读取application-profile.properties/yaml文件,并加载文件内激活的profile(如果有的话)
到这里已经读取到了所有的配置信息,主逻辑大概结束了,还差最后一个步骤:addLoadedPropertySources:
private void addLoadedPropertySources() { MutablePropertySources destination = this.environment.getPropertySources(); List<MutablePropertySources> loaded = new ArrayList<>(this.loaded.values()); Collections.reverse(loaded); String lastAdded = null; Set<String> added = new HashSet<>(); for (MutablePropertySources sources : loaded) { for (PropertySource<?> source : sources) { if (added.add(source.getName())) { addLoadedPropertySource(destination, lastAdded, source); lastAdded = source.getName(); } } } }
这里会将所有属性加入到“destination”,即environment.getPropertySources(),到这里,加载配置属性的逻辑就完成了。
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