本文主要从一些spring-cloud-config-server 包中的注解和类来分析配置中心是如何对外提供配置。
从@EnableConfigServer开始
为了让一个spring boot应用成为配置中心，我们需要使用@EnableConfigServer注解
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Import(ConfigServerConfiguration.class)
public @interface EnableConfigServer { }
可以看出，它引入了ConfigServerConfiguration
@Configuration
public class ConfigServerConfiguration {
class Marker {} @Bean
public Marker enableConfigServerMarker() {
return new Marker();
}
}
ConfigServerConfiguration 装配了一个MarkerBean。这个bean则有开启了ConfigServerAutoConfiguration(看下面的代码中的@ConditionalOnBean参数)
@Configuration
@ConditionalOnBean(ConfigServerConfiguration.Marker.class)
@EnableConfigurationProperties(ConfigServerProperties.class)
@Import({ EnvironmentRepositoryConfiguration.class, CompositeConfiguration.class, ResourceRepositoryConfiguration.class,
ConfigServerEncryptionConfiguration.class, ConfigServerMvcConfiguration.class, TransportConfiguration.class })
public class ConfigServerAutoConfiguration { }
这里又引入了多个配置类，包括:
EnvironmentRepositoryConfiguration
CompositeConfiguration
ResourceRepositoryConfiguration
ConfigServerEncryptionConfiguration
ConfigServerMvcConfiguration
TransportConfiguration
接下来介绍EnvironmentRepositoryConfiguration
EnvironmentRepositoryConfiguration
EnvironmentRepositoryConfiguration是配置中心的关键Configuration类。这个配置类中包含很多实现了EnvironmentRepository接口的类，每个实现类都对应一种类型(git/svn/navtie/vault)的配置。 EnvironmentRepositoryConfiguration通过profile注解（对当前应用的环境）决定使用装配哪个EnvironmentRepository Bean。默认是MultipleJGitEnvironmentRepository
@Configuration
@Import({ JdbcRepositoryConfiguration.class, VaultRepositoryConfiguration.class, SvnRepositoryConfiguration.class,
NativeRepositoryConfiguration.class, GitRepositoryConfiguration.class,
DefaultRepositoryConfiguration.class })
public class EnvironmentRepositoryConfiguration { @Bean
@ConditionalOnProperty(value = "spring.cloud.config.server.health.enabled", matchIfMissing = true)
public ConfigServerHealthIndicator configServerHealthIndicator(
EnvironmentRepository repository) {
return new ConfigServerHealthIndicator(repository);
} @Configuration
@ConditionalOnProperty(value = "spring.cloud.config.server.consul.watch.enabled")
protected static class ConsulEnvironmentWatchConfiguration { @Bean
public EnvironmentWatch environmentWatch() {
return new ConsulEnvironmentWatch();
}
} @Configuration
@ConditionalOnMissingBean(EnvironmentWatch.class)
protected static class DefaultEnvironmentWatch { @Bean
public EnvironmentWatch environmentWatch() {
return new EnvironmentWatch.Default();
}
}
} @Configuration
@ConditionalOnMissingBean(EnvironmentRepository.class)
class DefaultRepositoryConfiguration { @Autowired
private ConfigurableEnvironment environment; @Autowired
private ConfigServerProperties server; @Autowired(required = false)
private TransportConfigCallback transportConfigCallback; @Bean
public MultipleJGitEnvironmentRepository defaultEnvironmentRepository() {
MultipleJGitEnvironmentRepository repository = new MultipleJGitEnvironmentRepository(
this.environment);
repository.setTransportConfigCallback(this.transportConfigCallback);
if (this.server.getDefaultLabel() != null) {
repository.setDefaultLabel(this.server.getDefaultLabel());
}
return repository;
}
} @Configuration
@ConditionalOnMissingBean(EnvironmentRepository.class)
@Profile("native")
class NativeRepositoryConfiguration { @Autowired
private ConfigurableEnvironment environment; @Autowired
private ConfigServerProperties configServerProperties; @Bean
public NativeEnvironmentRepository nativeEnvironmentRepository() {
NativeEnvironmentRepository repository = new NativeEnvironmentRepository(
this.environment); repository.setDefaultLabel(configServerProperties.getDefaultLabel()); return repository;
}
} @Configuration
@Profile("git")
class GitRepositoryConfiguration extends DefaultRepositoryConfiguration {
} @Configuration
@Profile("subversion")
class SvnRepositoryConfiguration {
@Autowired
private ConfigurableEnvironment environment; @Autowired
private ConfigServerProperties server; @Bean
public SvnKitEnvironmentRepository svnKitEnvironmentRepository() {
SvnKitEnvironmentRepository repository = new SvnKitEnvironmentRepository(
this.environment);
if (this.server.getDefaultLabel() != null) {
repository.setDefaultLabel(this.server.getDefaultLabel());
}
return repository;
}
} @Configuration
@Profile("vault")
class VaultRepositoryConfiguration {
@Bean
public VaultEnvironmentRepository vaultEnvironmentRepository(
HttpServletRequest request, EnvironmentWatch watch) {
return new VaultEnvironmentRepository(request, watch, new RestTemplate());
}
} @Configuration
@Profile("jdbc")
class JdbcRepositoryConfiguration {
@Bean
public JdbcEnvironmentRepository jdbcEnvironmentRepository(JdbcTemplate jdbc) {
return new JdbcEnvironmentRepository(jdbc);
}
}
EnvironmentRepository
EnvironmentRepository是一个配置管理仓库接口，抽象了获取配置的方法:
Environment findOne(String application, String profile, String label);
它的实现类有很多，如下图所示:
从名字中大概可以看出，这些类应该是用于加载不同类型的配置（后面会再介绍）。
上面说的主要是configserver服务端如何自动配置和加载配置文件的，下面说说这些配置如何暴露在微服务系统中。对外提供接口的类，就是EnvironmentController
交互入口1：EnvironmentController
EnvironmentController是spring-cloud-config-server包的一个controller，其他服务一般是通过这个controller获取相应配置。
@RestController
@RequestMapping(method = RequestMethod.GET, path = "${spring.cloud.config.server.prefix:}")
public class EnvironmentController { private EnvironmentRepository repository;
private ObjectMapper objectMapper; public EnvironmentController(EnvironmentRepository repository,
ObjectMapper objectMapper) {
this.repository = repository;
this.objectMapper = objectMapper;
} // 获取配置的接口
... }
它的关键成员变量有两个：
一般情况Spring为EnvironmentController注入的类是EnvironmentEncryptorEnvironmentRepository。ObjectMapper用于当请求json格式的配置时的序列化。
EnvironmentController提供了多种获取配置的方法，这些方法主要接受application profile label这三个（或者更少）的参数，这三个参数的具体含义可以参考官网的说明，下面列举了部分方法：
@RequestMapping("/{name}/{profiles:.*[^-].*}")
public Environment defaultLabel(@PathVariable String name,
@PathVariable String profiles) {
return labelled(name, profiles, null);
}
@RequestMapping("/{name}/{profiles}/{label:.*}")
public Environment labelled(@PathVariable String name, @PathVariable String profiles,
@PathVariable String label) {
if (label != null && label.contains("(_)")) {
// "(_)" is uncommon in a git branch name, but "/" cannot be matched
// by Spring MVC
label = label.replace("(_)", "/");
}
Environment environment = this.repository.findOne(name, profiles, label);
return environment;
}
我们访问http://localhost:8081/config/mysql/dev(这是作者的配置，每个人可能不一样), 进入defaultLabel方法，它会再调用labelled方法（由于没有制定label参数，所以label传了个null）。
@RequestMapping("/{name}/{profiles}/{label:.*}")
public Environment labelled(@PathVariable String name, @PathVariable String profiles,
@PathVariable String label) {
if (name != null && name.contains("(_)")) {
// "(_)" is uncommon in a git repo name, but "/" cannot be matched
// by Spring MVC
name = name.replace("(_)", "/");
}
if (label != null && label.contains("(_)")) {
// "(_)" is uncommon in a git branch name, but "/" cannot be matched
// by Spring MVC
label = label.replace("(_)", "/");
}
StopWatch sw = new StopWatch("labelled");
sw.start();
logger.info("EnvironmentController.labelled()开始,name={},profiles={},label={}", name, profiles, label);
Environment environment = this.repository.findOne(name, profiles, label);
sw.stop();
logger.info("EnvironmentController.labelled()结束,name={},profiles={},label={},耗时={}", name, profiles, label, sw.getTotalTimeMillis());
return environment;
}
在labelled方法中，会调用repository的findOne()来加载配置，然后返回给配置获取方。
各式各样的配置仓库类
EnvironmentEncryptorEnvironmentRepository
前面提到spring config 通过EnvironmentEncryptorEnvironmentRepository加载配置
public class EnvironmentEncryptorEnvironmentRepository implements EnvironmentRepository {
private EnvironmentRepository delegate;
private EnvironmentEncryptor environmentEncryptor;
public EnvironmentEncryptorEnvironmentRepository(EnvironmentRepository delegate,
EnvironmentEncryptor environmentEncryptor) {
this.delegate = delegate;
this.environmentEncryptor = environmentEncryptor;
}
@Override
public Environment findOne(String name, String profiles, String label) {
Environment environment = this.delegate.findOne(name, profiles, label);
if (this.environmentEncryptor != null) {
environment = this.environmentEncryptor.decrypt(environment);
}
if (!this.overrides.isEmpty()) {
environment.addFirst(new PropertySource("overrides", this.overrides));
}
return environment;
}
}
它有一个解密器environmentEncryptor用于对加密存放的配置进行解密，另外包含一个EnvironmentRepository的实现类delegate，这里注入的类是SearchPathCompositeEnvironmentRepository
SearchPathCompositeEnvironmentRepository
SearchPathCompositeEnvironmentRepository本身并没有findOne()方法，由它的父类CompositeEnvironmentRepository实现。
public class SearchPathCompositeEnvironmentRepository extends CompositeEnvironmentRepository implements SearchPathLocator {
public SearchPathCompositeEnvironmentRepository(List<EnvironmentRepository> environmentRepositories) {
super(environmentRepositories);
}
}
CompositeEnvironmentRepository
CompositeEnvironmentRepository有一个EnvironmentRepository的列表。从它的findOne()方法可以看出：当有多个配置存放方式时，CompositeEnvironmentRepository会遍历所有EnvironmentRepository来获取所有配置。
public class CompositeEnvironmentRepository implements EnvironmentRepository {
protected List<EnvironmentRepository> environmentRepositories;
public CompositeEnvironmentRepository(List<EnvironmentRepository> environmentRepositories) {
//Sort the environment repositories by the priority
Collections.sort(environmentRepositories, OrderComparator.INSTANCE);
this.environmentRepositories = environmentRepositories;
}
@Override
public Environment findOne(String application, String profile, String label) {
Environment env = new Environment(application, new String[]{profile}, label, null, null);
if(environmentRepositories.size() == 1) {
Environment envRepo = environmentRepositories.get(0).findOne(application, profile, label);
env.addAll(envRepo.getPropertySources());
env.setVersion(envRepo.getVersion());
env.setState(envRepo.getState());
} else {
//遍历
for (EnvironmentRepository repo : environmentRepositories) {
env.addAll(repo.findOne(application, profile, label).getPropertySources());
}
}
return env;
}
}
小结一下：虽然实现了EnvironmentRepository接口。但EnvironmentEncryptorEnvironmentRepository只是一个代理， SearchPathCompositeEnvironmentRepository/CompositeEnvironmentRepository也没有具体加载配置的逻辑。
而真正加载配置的类存放在CompositeEnvironmentRepository的environmentRepositories列表。
包括：NativeEnvironmentRepository: 获取本地配置；SvnRepositoryConfiguration: 获取存放在svn中的配置；VaultEnvironmentRepository: 获取存放在vault中的配置；GitRepositoryConfiguration:获取存放在git中的配置；
接下来介绍NativeEnvironmentRepository。
NativeEnvironmentRepository
NativeEnvironmentRepository 用于加载本地(native)配置。它加载配置时，其实是以特定环境（传入的profile）启动了另外一个微型spring boot应用，通过这个应用获取所有的配置，然后调用clean过滤，得到所需配置。
@ConfigurationProperties("spring.cloud.config.server.native")
public class NativeEnvironmentRepository
implements EnvironmentRepository, SearchPathLocator, Ordered {
@Override
public Environment findOne(String config, String profile, String label) {
SpringApplicationBuilder builder = new SpringApplicationBuilder(
PropertyPlaceholderAutoConfiguration.class);
ConfigurableEnvironment environment = getEnvironment(profile);
builder.environment(environment);
builder.web(false).bannerMode(Mode.OFF);
if (!logger.isDebugEnabled()) {
// Make the mini-application startup less verbose
builder.logStartupInfo(false);
}
String[] args = getArgs(config, profile, label);
// Explicitly set the listeners (to exclude logging listener which would change
// log levels in the caller)
builder.application()
.setListeners(Arrays.asList(new ConfigFileApplicationListener()));
ConfigurableApplicationContext context = builder.run(args);
environment.getPropertySources().remove("profiles");
try {
return clean(new PassthruEnvironmentRepository(environment).findOne(config,
profile, label));
}
finally {
context.close();
}
}
private ConfigurableEnvironment getEnvironment(String profile) {
ConfigurableEnvironment environment = new StandardEnvironment();
environment.getPropertySources()
.addFirst(new MapPropertySource("profiles",
Collections.<String, Object>singletonMap("spring.profiles.active",
profile)));
return environment;
}
protected Environment clean(Environment value) {
Environment result = new Environment(value.getName(), value.getProfiles(),
value.getLabel(), this.version, value.getState());
for (PropertySource source : value.getPropertySources()) {
String name = source.getName();
if (this.environment.getPropertySources().contains(name)) {
continue;
}
name = name.replace("applicationConfig: [", "");
name = name.replace("]", "");
if (this.searchLocations != null) {
boolean matches = false;
String normal = name;
if (normal.startsWith("file:")) {
normal = StringUtils
.cleanPath(new File(normal.substring("file:".length()))
.getAbsolutePath());
}
String profile = result.getProfiles() == null ? null
: StringUtils.arrayToCommaDelimitedString(result.getProfiles());
for (String pattern : getLocations(result.getName(), profile,
result.getLabel()).getLocations()) {
if (!pattern.contains(":")) {
pattern = "file:" + pattern;
}
if (pattern.startsWith("file:")) {
pattern = StringUtils
.cleanPath(new File(pattern.substring("file:".length()))
.getAbsolutePath())
+ "/";
}
if (logger.isTraceEnabled()) {
logger.trace("Testing pattern: " + pattern
+ " with property source: " + name);
}
if (normal.startsWith(pattern)
&& !normal.substring(pattern.length()).contains("/")) {
matches = true;
break;
}
}
if (!matches) {
// Don't include this one: it wasn't matched by our search locations
if (logger.isDebugEnabled()) {
logger.debug("Not adding property source: " + name);
}
continue;
}
}
logger.info("Adding property source: " + name);
result.add(new PropertySource(name, source.getSource()));
}
return result;
}
}
交互入口2：ConfigServerHealthIndicator，健康检查
ConfigServerHealthIndicator怎么加入到HealthEndpoint的，及怎么被调用的：
上面的调用是遍历indicators，每个indicator代表一种健康检查的HealthIndicator的实现类。
这些indicator是怎么加入的呢？
根据HealthIndicator接口类调用BeanFactoryUtils.beanNamesForTypeIncludingAncestors(this, requiredType, true, descriptor.isEager());找到所有实现类。然后把它放到上面的indicators里。
在EndpointAutoConfiguration的构造函数中，发起上述的调用。
在具体看ConfigServerHealthIndicator
config-server和config-server client都有这个类，用于对资源配置中心的EnvironmentRepository是否正常工作的检测。
config-server服务端
config-server服务端的健康检查的自动配置的代码如下，同时可见spring.cloud.config.server.health.enabled的配置项是一个开关。
@Configuration
@Import({ JdbcRepositoryConfiguration.class, VaultRepositoryConfiguration.class, SvnRepositoryConfiguration.class,
NativeRepositoryConfiguration.class, GitRepositoryConfiguration.class,
DefaultRepositoryConfiguration.class })
public class EnvironmentRepositoryConfiguration { @Bean
@ConditionalOnProperty(value = "spring.cloud.config.server.health.enabled", matchIfMissing = true)
public ConfigServerHealthIndicator configServerHealthIndicator(
EnvironmentRepository repository) {
return new ConfigServerHealthIndicator(repository);
}
config-server端的ConfigServerHealthIndicator的源码：
@ConfigurationProperties("spring.cloud.config.server.health")
public class ConfigServerHealthIndicator extends AbstractHealthIndicator {
private EnvironmentRepository environmentRepository;
private Map<String, Repository> repositories = new LinkedHashMap<>();
public ConfigServerHealthIndicator(EnvironmentRepository environmentRepository) {
this.environmentRepository = environmentRepository;
}
@PostConstruct
public void init() {
if (this.repositories.isEmpty()) {
this.repositories.put("app", new Repository());
}
}
@Override
protected void doHealthCheck(Health.Builder builder) throws Exception {
builder.up();
List<Map<String, Object>> details = new ArrayList<>();
for (String name : this.repositories.keySet()) {
Repository repository = this.repositories.get(name);
String application = (repository.getName() == null)? name : repository.getName();
String profiles = repository.getProfiles();
try {
Environment environment = this.environmentRepository.findOne(application, profiles, repository.getLabel());
HashMap<String, Object> detail = new HashMap<>();
detail.put("name", environment.getName());
detail.put("label", environment.getLabel());
if (environment.getProfiles() != null && environment.getProfiles().length > 0) {
detail.put("profiles", Arrays.asList(environment.getProfiles()));
}
if (!CollectionUtils.isEmpty(environment.getPropertySources())) {
List<String> sources = new ArrayList<>();
for (PropertySource source : environment.getPropertySources()) {
sources.add(source.getName());
}
detail.put("sources", sources);
}
details.add(detail);
} catch (Exception e) {
HashMap<String, String> map = new HashMap<>();
map.put("application", application);
map.put("profiles", profiles);
builder.withDetail("repository", map);
builder.down(e);
return;
}
}
builder.withDetail("repositories", details);
}
config-server client端
config-server client端的健康检查的自动配置的代码如下，同时可见health.config.enabled是是否对config-server的健康检查的开关（config-server端的资源配置中心的EnvironmentRepository是否正常工作的检测）
@Configuration
public class ConfigClientAutoConfiguration {
@Configuration
@ConditionalOnClass(HealthIndicator.class)
@ConditionalOnBean(ConfigServicePropertySourceLocator.class)
@ConditionalOnProperty(value = "health.config.enabled", matchIfMissing = true)
protected static class ConfigServerHealthIndicatorConfiguration { @Bean
public ConfigServerHealthIndicator configServerHealthIndicator(
ConfigServicePropertySourceLocator locator,
ConfigClientHealthProperties properties, Environment environment) {
return new ConfigServerHealthIndicator(locator, environment, properties);
}
}
健康检查的核心代码：
public class ConfigServerHealthIndicator extends AbstractHealthIndicator {
public ConfigServerHealthIndicator(ConfigServicePropertySourceLocator locator,
Environment environment, ConfigClientHealthProperties properties) {
this.environment = environment;
this.locator = locator;
this.properties = properties;
}
@Override
protected void doHealthCheck(Builder builder) throws Exception {
PropertySource<?> propertySource = getPropertySource();
builder.up();
if (propertySource instanceof CompositePropertySource) {
List<String> sources = new ArrayList<>();
for (PropertySource<?> ps : ((CompositePropertySource) propertySource).getPropertySources()) {
sources.add(ps.getName());
}
builder.withDetail("propertySources", sources);
} else if (propertySource!=null) {
builder.withDetail("propertySources", propertySource.toString());
} else {
builder.unknown().withDetail("error", "no property sources located");
}
}