spring cloud config配置中心源碼分析之註解@EnableConfigServer
基於spring-cloud-config-server-2.0.2.RELEASE代碼
spring cloud config的主函數是ConfigServerApplication，其定義如下：
package com.liuwen;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.config.server.EnableConfigServer;
@SpringBootApplication
@EnableConfigServer
public class ConfigServerApplication {
public static void main(String[] args){
SpringApplication.run(ConfigServerApplication.class,args);
}
}
@EnableConfigServer是spring cloud定義的註解，
@EnableConfigServer定義如下：
@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 {
public ConfigServerConfiguration() {
}
@Bean
public ConfigServerConfiguration.Marker enableConfigServerMarker() {
return new ConfigServerConfiguration.Marker();
}
class Marker {
Marker() {
}
}
}
ConfigServerConfiguration類裏面並沒有實現太多bean的裝配，這裏利用一種折中方式，引入需要的自動配置。請看下面的類。Marker唯一被引用的地方在ConfigServerAutoConfiguration類。
ConfigServerConfiguration 裝配了一個Marker的Bean。這個bean則有開啓了ConfigServerAutoConfiguration。
@Configuration
@ConditionalOnBean({Marker.class})
@EnableConfigurationProperties({ConfigServerProperties.class})
@Import({EnvironmentRepositoryConfiguration.class, CompositeConfiguration.class, ResourceRepositoryConfiguration.class, ConfigServerEncryptionConfiguration.class, ConfigServerMvcConfiguration.class})
public class ConfigServerAutoConfiguration {
public ConfigServerAutoConfiguration() {
}
}
這裏又引入了多個配置類，包括:
EnvironmentRepositoryConfiguration
CompositeConfiguration
ResourceRepositoryConfiguration
ConfigServerEncryptionConfiguration
ConfigServerMvcConfiguration
TransportConfiguration
接下來介紹EnvironmentRepositoryConfiguration
EnvironmentRepositoryConfiguration是配置中心的關鍵Configuration類。這個配置類中包含很多實現了EnvironmentRepository接口的類，每個實現類都對應一種類型(git/svn/navtie/vault)的配置。 EnvironmentRepositoryConfiguration通過profile註解（對當前應用的環境）決定使用裝配哪個EnvironmentRepository Bean。默認是MultipleJGitEnvironmentRepository(在內部類DefaultRepositoryConfiguration裏面有)。
@Configuration
public class EnvironmentRepositoryConfiguration {
@Bean
@ConditionalOnProperty(value = "spring.cloud.config.server.health.enabled", matchIfMissing = true)
public ConfigServerHealthIndicator configServerHealthIndicator(EnvironmentRepository repository) {
return new ConfigServerHealthIndicator(repository);
}
@Configuration
@ConditionalOnMissingBean(EnvironmentRepository.class)
protected static 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
@Profile("native")
protected static class NativeRepositoryConfiguration {
@Autowired
private ConfigurableEnvironment environment;
@Bean
public NativeEnvironmentRepository nativeEnvironmentRepository() {
return new NativeEnvironmentRepository(this.environment);
}
}
@Configuration
@Profile("git")
protected static class GitRepositoryConfiguration extends DefaultRepositoryConfiguration {}
@Configuration
@Profile("subversion")
protected static 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")
protected static class VaultConfiguration {
@Bean
public VaultEnvironmentRepository vaultEnvironmentRepository(HttpServletRequest request, EnvironmentWatch watch) {
return new VaultEnvironmentRepository(request, watch, new RestTemplate());
}
}
@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();
}
}
}
EnvironmentRepository
EnvironmentRepository是一個配置管理倉庫接口，抽象了獲取配置的方法:
Environment findOne(String application, String profile, String label);
它的實現類有很多，如下圖所示:
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從名字中大概可以看出，這些類應該是用於加載不同類型的配置（後面會再介紹）。
有了獲取配置的類，還差對外提供接口的類，就是EnvironmentController
入口：EnvironmentController
EnvironmentController是spring-cloud-config-server包的一個controller，其他服務一般是通過這個controller獲取相應配置。
@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;
}
// 獲取配置的接口
...
}
它的關鍵成員變量有兩個：
一般情況Spring爲EnvironmentController注入的類是EnvironmentEncryptorEnvironmentRepository。
ObjectMapper用於當請求json格式的配置時的序列化。
EnvironmentController提供了多種獲取配置的方法，這些方法主要接受application profile label這三個（或者更少）的參數，這三個參數的具體含義可以參考官網的說明，下面列舉了部分方法：
@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;
}
我們訪問http://localhost:8081/config/mysql/dev(這是作者的配置，每個人可能不一樣), 進入defaultLabel方法，它會再調用labelled方法（由於沒有制定label參數，所以label傳了個null）。
@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("(_)", "/");
}
// 調用`EnvironmentRepository`的findOne方法返回對應的配置
Environment environment = this.repository.findOne(name, profiles, label);
return environment;
}
在labelled方法中，會調用EnvironmentRepository的findOne()來加載配置，然後返回給配置獲取方。
各式各樣的配置倉庫類
EnvironmentEncryptorEnvironmentRepository
前面提到spring config 通過EnvironmentEncryptorEnvironmentRepository加載配置
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;
}
}
它有一個解密器environmentEncryptor用於對加密存放的配置進行解密，另外包含一個EnvironmentRepository的實現類delegate，這裏注入的類是SearchPathCompositeEnvironmentRepository
SearchPathCompositeEnvironmentRepository
SearchPathCompositeEnvironmentRepository本身並沒有findOne()方法，由它的父類CompositeEnvironmentRepository實現。
public class SearchPathCompositeEnvironmentRepository extends CompositeEnvironmentRepository implements SearchPathLocator {
public SearchPathCompositeEnvironmentRepository(List<EnvironmentRepository> environmentRepositories) {
super(environmentRepositories);
}
}
CompositeEnvironmentRepository
CompositeEnvironmentRepository有一個EnvironmentRepository的列表。從它的findOne()方法可以看出：當有多個配置存放方式時，CompositeEnvironmentRepository會遍歷所有EnvironmentRepository來獲取所有配置
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 {
for (EnvironmentRepository repo : environmentRepositories) {
env.addAll(repo.findOne(application, profile, label).getPropertySources());
}
}
return env;
}
}
小結一下：雖然實現了EnvironmentRepository接口。但EnvironmentEncryptorEnvironmentRepository只是一個代理， SearchPathCompositeEnvironmentRepository/CompositeEnvironmentRepository也沒有具體加載配置的邏輯。
而真正加載配置的類存放在CompositeEnvironmentRepository的environmentRepositories列表。
包括：
NativeEnvironmentRepository: 獲取本地配置；
SvnRepositoryConfiguration: 獲取存放在svn中的配置；
VaultEnvironmentRepository: 獲取存放在vault中的配置；
GitRepositoryConfiguration:獲取存放在git中
NativeEnvironmentRepository
NativeEnvironmentRepository 用於加載本地(native)配置。它加載配置時，其實是以特定環境（傳入的profile）啓動了另外一個微型spring boot應用，通過這個應用獲取所有的配置，然後調用clean過濾，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;
}
}
嘗試自定義EnvironmentRepository 實現
在上面的分析可以知道，所有的配置EnvironmentRepository的Configuration都是在沒有EnvironmentRepository的bean的時候纔會生效，我們可以實現自定義的EnvironmentRepository的bean，然後就可以覆蓋的系統的實現。代碼如下。
@SpringBootApplication
@EnableConfigServer
public class SpringCloudDefineConfigServer {
public static void main(String[] args) {
SpringApplication.run(SpringCloudDefineConfigServer.class, args);
}
@Bean
public EnvironmentRepository newEnvironmentRepository(){
return new EnvironmentRepository() {
@Override
public Environment findOne(String application, String profile, String label) {
Environment environment =new Environment(application, profile);
List<PropertySource> propertySourceList = environment.getPropertySources();
Map<String, String> map = new HashMap<>();
map.put("name", "garine-define");
PropertySource propertySource = new PropertySource("map", map);
propertySourceList.add(propertySource);
return environment;
}
};
}
}
spring cloud config client實現原理分析
getRemoteEnvironment
前面說到，調用EnvironmentController接口返回的是Environment的json串，那麼client這邊反序列化應該也是Environment，搜索spring-cloud-config-client包使用Environment的地方，發現這個方法。
org.springframework.cloud.config.client.ConfigServicePropertySourceLocator#getRemoteEnvironment，目測就是獲取遠程服務器配置的地方。代碼如下：
private Environment getRemoteEnvironment(RestTemplate restTemplate,
ConfigClientProperties properties, String label, String state) {
String path = "/{name}/{profile}";
String name = properties.getName();
String profile = properties.getProfile();
String token = properties.getToken();
int noOfUrls = properties.getUri().length;
if (noOfUrls > 1) {
logger.info("Multiple Config Server Urls found listed.");
}
Object[] args = new String[] { name, profile };
if (StringUtils.hasText(label)) {
if (label.contains("/")) {
label = label.replace("/", "(_)");
}
args = new String[] { name, profile, label };
path = path + "/{label}";
}
ResponseEntity<Environment> response = null;
for (int i = 0; i < noOfUrls; i++) {
Credentials credentials = properties.getCredentials(i);
String uri = credentials.getUri();
String username = credentials.getUsername();
String password = credentials.getPassword();
logger.info("Fetching config from server at : " + uri);
try {
HttpHeaders headers = new HttpHeaders();
addAuthorizationToken(properties, headers, username, password);
if (StringUtils.hasText(token)) {
headers.add(TOKEN_HEADER, token);
}
if (StringUtils.hasText(state) && properties.isSendState()) {
headers.add(STATE_HEADER, state);
}
final HttpEntity<Void> entity = new HttpEntity<>((Void) null, headers);
response = restTemplate.exchange(uri + path, HttpMethod.GET, entity,
Environment.class, args);
}
catch (HttpClientErrorException e) {
if (e.getStatusCode() != HttpStatus.NOT_FOUND) {
throw e;
}
}
catch (ResourceAccessException e) {
logger.info("Connect Timeout Exception on Url - " + uri
+ ". Will be trying the next url if available");
if (i == noOfUrls - 1)
throw e;
else
continue;
}
if (response == null || response.getStatusCode() != HttpStatus.OK) {
return null;
}
Environment result = response.getBody();
return result;
}
return null;
}
上面的代碼主要操作就是拼接一個請求配置地址串，獲取所需的ApplicationName，profile，label參數，利用RestTemplate執行http請求，返回的json反序列化爲Environment，從而獲得所需要的配置信息。
那麼問題來了，client是在什麼時候調用getRemoteEnvironment方法的，推測應該是在boostrap context進行初始化階段。在getRemoteEnvironment打個斷點，重啓client程序，可以查看到以下調用鏈路。
- org.springframework.boot.SpringApplication#run(java.lang.String…)
- org.springframework.boot.SpringApplication#prepareContext
- org.springframework.boot.SpringApplication#applyInitializers
- org.springframework.cloud.bootstrap.config.PropertySourceBootstrapConfiguration#initialize
- org.springframework.cloud.config.client.ConfigServicePropertySourceLocator#locate
- org.springframework.cloud.config.client.ConfigServicePropertySourceLocator#getRemoteEnvironment
所以，可以知道在spring啓動時就會遠程加載配置信息，SpringApplication#applyInitializers代碼如下，會遍歷所有initializer進行一遍操作，PropertySourceBootstrapConfiguration就是其中之一的initializer。
protected void applyInitializers(ConfigurableApplicationContext context) {
for (ApplicationContextInitializer initializer : getInitializers()) {
Class<?> requiredType = GenericTypeResolver.resolveTypeArgument(
initializer.getClass(), ApplicationContextInitializer.class);
Assert.isInstanceOf(requiredType, context, "Unable to call initializer.");
initializer.initialize(context);
}
}
當引入了spring-cloud-config後PropertySourceBootstrapConfiguration#propertySourceLocators中會新增一個ConfigServicePropertySourceLocator實例。在PropertySourceBootstrapConfiguration#initialize中遍歷propertySourceLocators的locate方法，然後讀取遠程服務配置信息；如果沒有引入了spring-cloud-config，那麼propertySourceLocators將會是空集合。代碼如下。
@Override
public void initialize(ConfigurableApplicationContext applicationContext) {
CompositePropertySource composite = new CompositePropertySource(
BOOTSTRAP_PROPERTY_SOURCE_NAME);
AnnotationAwareOrderComparator.sort(this.propertySourceLocators);
boolean empty = true;
ConfigurableEnvironment environment = applicationContext.getEnvironment();
for (PropertySourceLocator locator : this.propertySourceLocators) {
PropertySource<?> source = null;
source = locator.locate(environment);
if (source == null) {
continue;
}
logger.info("Located property source: " + source);
composite.addPropertySource(source);
empty = false;
}
if (!empty) {
MutablePropertySources propertySources = environment.getPropertySources();
String logConfig = environment.resolvePlaceholders("${logging.config:}");
LogFile logFile = LogFile.get(environment);
if (propertySources.contains(BOOTSTRAP_PROPERTY_SOURCE_NAME)) {
propertySources.remove(BOOTSTRAP_PROPERTY_SOURCE_NAME);
}
insertPropertySources(propertySources, composite);
reinitializeLoggingSystem(environment, logConfig, logFile);
setLogLevels(applicationContext, environment);
handleIncludedProfiles(environment);
}
}
PropertySourceBootstrapConfiguration#propertySourceLocators初始化
@Autowired(required = false)
private List<PropertySourceLocator> propertySourceLocators = new ArrayList<>();
上面的代碼可以看出，這裏的propertySourceLocators是直接注入上下文中管理的PropertySourceLocator實例，所以PropertySourceLocator一定有別的地方初始化。
搜索ConfigServicePropertySourceLocator的使用處，發現org.springframework.cloud.config.client.ConfigServiceBootstrapConfiguration#configServicePropertySource方法裝配了一個ConfigServicePropertySourceLocator的bean，代碼如下。
@Configuration
@EnableConfigurationProperties
public class ConfigServiceBootstrapConfiguration {
@Bean
@ConditionalOnMissingBean(ConfigServicePropertySourceLocator.class)
@ConditionalOnProperty(value = "spring.cloud.config.enabled", matchIfMissing = true)
public ConfigServicePropertySourceLocator configServicePropertySource(ConfigClientProperties properties) {
ConfigServicePropertySourceLocator locator = new ConfigServicePropertySourceLocator(
properties);
return locator;
}
//........
}
org.springframework.cloud.config.client.ConfigServiceBootstrapConfiguration是config client的類，當引入了spring cloud config時引入，再嘗試搜索使用處，發現在spring cloud config client包裏面的spring.factories裏面引入了ConfigServiceBootstrapConfiguration，熟悉spring boot自動裝配的都知道，程序會自動加載spring.factories裏面的配置類。
也就是說，當引入了spring cloud config client包，就會自動加載ConfigServiceBootstrapConfiguration類，自動裝配ConfigServiceBootstrapConfiguration裏面配置的bean，也就自動實例化一個ConfigServicePropertySourceLocator。
# Auto Configure
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
org.springframework.cloud.config.client.ConfigClientAutoConfiguration
# Bootstrap components
org.springframework.cloud.bootstrap.BootstrapConfiguration=\
org.springframework.cloud.config.client.ConfigServiceBootstrapConfiguration,\
org.springframework.cloud.config.client.DiscoveryClientConfigServiceBootstrapConfiguration