Abstract: the original source www.iocoder.cn/Eureka/eure… “Taro source” welcome to reprint, keep the summary, thank you!

This article is mainly based on Eureka version 1.8.X

• 1. An overview of the
• 2. EurekaBootStrap
  • 2.1 Initializing the Eureka-Server Configuration Environment
  • 2.2 Initializing the Eureka-Server Context
• 3. Filter
  • 3.1 StatusFilter
  • 3.2 ServerRequestAuthFilter
  • 3.3 RateLimitingFilter
  • 3.4 GzipEncodingEnforcingFilter
  • 3.5 ServletContainer
• 666. The eggs

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1. An overview of the

This article is based on “Eureka source code parsing — EurekaServer startup (1) EurekaServer VerConfig”, mainly share the second part of EurekaServer startup process — EurekaBootStrap.

Considering the amount of code involved in the entire initialization process, this article is divided into two parts:

• ServerConfig
• 【 article 】EurekaBootStrap

2. EurekaBootStrap

Com.net flix. Eureka. EurekaBootStrap, eureka – Server startup entries.

EurekaBootStrap implements javax.mail. Servlet. ServletContextListener interface, in the servlet container (such as Tomcat, Jetty) starts, Call the #contextInitialized() method to initialize eureka-server with the following code:

Public class EurekaBootStrap implements ServletContextListener {public class EurekaBootStrap implements ServletContextListener ContextInitialized (ServletContextEvent Event) {try {// Initialize the Eureka-server configuration environment initEurekaEnvironment(); // Initialize the Eureka-server context initEurekaServerContext(); ServletContext sc = event.getServletContext(); sc.setAttribute(EurekaServerContext.class.getName(), serverContext); } catch (Throwable e) { logger.error("Cannot bootstrap eureka server :", e); throw new RuntimeException("Cannot bootstrap eureka server :", e); }}}Copy the code

• call#initEurekaEnvironment()Method to initialize eureka-serverconfigurationThe environment.
• call#initEurekaServerContext()Method to initialize the Eureka-server context.

2.1 Initializing the Eureka-Server Configuration Environment

// EurekaBootStrap.java private static final String TEST = "test"; private static final String ARCHAIUS_DEPLOYMENT_ENVIRONMENT = "archaius.deployment.environment"; private static final String EUREKA_ENVIRONMENT = "eureka.environment"; private static final String CLOUD = "cloud"; private static final String DEFAULT = "default"; private static final String ARCHAIUS_DEPLOYMENT_DATACENTER = "archaius.deployment.datacenter"; private static final String EUREKA_DATACENTER = "eureka.datacenter"; protected void initEurekaEnvironment() throws Exception { logger.info("Setting the eureka configuration.." ); / / set the configuration file data center String dataCenter. = ConfigurationManager getConfigInstance () get String (EUREKA_DATACENTER); if (dataCenter == null) { logger.info("Eureka data center value eureka.datacenter is not set, defaulting to default"); ConfigurationManager.getConfigInstance().setProperty(ARCHAIUS_DEPLOYMENT_DATACENTER, DEFAULT); } else { ConfigurationManager.getConfigInstance().setProperty(ARCHAIUS_DEPLOYMENT_DATACENTER, dataCenter); } / / set the configuration file environment String environment. = ConfigurationManager getConfigInstance () get String (EUREKA_ENVIRONMENT); if (environment == null) { ConfigurationManager.getConfigInstance().setProperty(ARCHAIUS_DEPLOYMENT_ENVIRONMENT, TEST); logger.info("Eureka environment value eureka.environment is not set, defaulting to test"); }}Copy the code

2.2 Initializing the Eureka-Server Context

The #initEurekaServerContext() method of EurekaBootStrap contains a lot of code.

2.2.1 Creating the Eureka-Server Configuration

EurekaServerConfig eurekaServerConfig = new DefaultEurekaServerConfig();Copy the code

2.2.2 Data compatibility between eureka-Server request and response

// For backward compatibility
JsonXStream.getInstance().registerConverter(new V1AwareInstanceInfoConverter(), XStream.PRIORITY_VERY_HIGH);
XmlXStream.getInstance().registerConverter(new V1AwareInstanceInfoConverter(), XStream.PRIORITY_VERY_HIGH);Copy the code

• At present, Eureka-Server provides V2 version API, and the above code is mainly compatible with V1 version API. You can skip it.

2.2.3 Creating the Eureka-Server request and response codec

logger.info("Initializing the eureka client..." ); logger.info(eurekaServerConfig.getJsonCodecName()); ServerCodecs serverCodecs = new DefaultServerCodecs(eurekaServerConfig);Copy the code

2.2.4 create Eureka – Client

ApplicationInfoManager applicationInfoManager; if (eurekaClient == null) { EurekaInstanceConfig instanceConfig = isCloud(ConfigurationManager.getDeploymentContext()) ?  new CloudInstanceConfig() : new MyDataCenterInstanceConfig(); applicationInfoManager = new ApplicationInfoManager( instanceConfig, new EurekaConfigBasedInstanceInfoProvider(instanceConfig).get()); EurekaClientConfig eurekaClientConfig = new DefaultEurekaClientConfig(); eurekaClient = new DiscoveryClient(applicationInfoManager, eurekaClientConfig); } else { applicationInfoManager = eurekaClient.getApplicationInfoManager(); }Copy the code

• Eureka-server is embedded with Eureka-client, which is used to communicate with other nodes in the Eureka-Server cluster.
• Eureka-client initialization process, Eureka source code parsing — EurekaClient (3) EurekaClient “DiscoveryClient” is explained in detail.

• Eureka-client can also be passed through the EurekaBootStrap constructor.

  public class EurekaBootStrap implements ServletContextListener { private EurekaClient eurekaClient; public EurekaBootStrap(EurekaClient eurekaClient) { this.eurekaClient = eurekaClient; }}Copy the code

  • Not in most cases.

2.2.5 Creating a Registry for Application Instance Information

PeerAwareInstanceRegistry registry; If (isAws (applicationInfoManager getInfo ())) {/ / AWS, Skip the registry = new AwsInstanceRegistry (eurekaServerConfig, eurekaClient getEurekaClientConfig (), serverCodecs, eurekaClient ); awsBinder = new AwsBinderDelegate(eurekaServerConfig, eurekaClient.getEurekaClientConfig(), registry, applicationInfoManager); awsBinder.start(); } else { registry = new PeerAwareInstanceRegistryImpl( eurekaServerConfig, eurekaClient.getEurekaClientConfig(), serverCodecs, eurekaClient ); }Copy the code

2.2.6 Creating a Node set in the Eureka-Server Cluster

PeerEurekaNodes peerEurekaNodes = getPeerEurekaNodes(
      registry,
      eurekaServerConfig,
      eurekaClient.getEurekaClientConfig(),
      serverCodecs,
      applicationInfoManager
);Copy the code

• com.netflix.eureka.cluster.PeerEurekaNodes, eureka-server cluster node set, inEureka — Eureka-Server cluster SynchronizationDetailed analysis.

2.2.7 Creating a Eureka-Server Context

serverContext = new DefaultEurekaServerContext(
      eurekaServerConfig,
      serverCodecs,
      registry,
      peerEurekaNodes,
      applicationInfoManager
);Copy the code

• com.netflix.eureka.EurekaServerContext, eureka-server contextinterface, which provides the internal component object of eureka-ServerInitialize the,Shut down,To obtainMethods.

• Com.net flix. Eureka. EurekaServerContext DefaultEurekaServerContext, eureka – Server context implementation class, the implementation code is as follows:

  public class DefaultEurekaServerContext implements EurekaServerContext { private final EurekaServerConfig serverConfig; private final ServerCodecs serverCodecs; private final PeerAwareInstanceRegistry registry; private final PeerEurekaNodes peerEurekaNodes; private final ApplicationInfoManager applicationInfoManager; / /... Omit method}Copy the code

2.2.8 initialization EurekaServerContextHolder

EurekaServerContextHolder.initialize(serverContext);Copy the code

2.2.9 Initializing the Eureka-Server Context

serverContext.initialize();
logger.info("Initialized server context");Copy the code

• To initialize the Eureka-Server context, call the ServerContext#initialize() method:

  // DefaultEurekaServerContext.java @Override public void initialize() throws Exception { logger.info("Initializing ..." ); // Start the eureka-server cluster node set (replication) peerEurekaNodes. Start (); // Initialize registry. Init (peerEurekaNodes) for application instance information; logger.info("Initialized"); }Copy the code

2.2.10 Pull registration information from other Eureka-servers

// Copy registry from neighboring eureka node
int registryCount = registry.syncUp();
registry.openForTraffic(applicationInfoManager, registryCount);Copy the code

2.2.11 Registration Monitoring

// Register all monitoring statistics.
EurekaMonitors.registerAllStats();Copy the code

• Cooperate with Netflix Servo to realize monitoring information collection.

3. Filter

3.1 StatusFilter

Com.net flix. Eureka. StatusFilter, eureka – Server status filter. If eureka-server is not in InstanceStatus.UP state, return HTTP status code 307 redirection as follows:

// StatusFilter.java private static final int SC_TEMPORARY_REDIRECT = 307; public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { InstanceInfo myInfo = ApplicationInfoManager.getInstance().getInfo(); InstanceStatus status = myInfo.getStatus(); if (status ! = InstanceStatus.UP && response instanceof HttpServletResponse) { HttpServletResponse httpRespone = (HttpServletResponse) response; httpRespone.sendError(SC_TEMPORARY_REDIRECT, "Current node is currently not ready to serve requests -- current status: " + status + " - try another DS node: "); } chain.doFilter(request, response); }Copy the code

3.2 ServerRequestAuthFilter

// ServerRequestAuthFilter.java protected void logAuth(ServletRequest request) { if (serverConfig.shouldLogIdentityHeaders()) { if (request instanceof HttpServletRequest) { HttpServletRequest httpRequest = (HttpServletRequest) request; String clientName = getHeader(httpRequest, AbstractEurekaIdentity.AUTH_NAME_HEADER_KEY); String clientVersion = getHeader(httpRequest, AbstractEurekaIdentity.AUTH_VERSION_HEADER_KEY); DynamicCounter.increment(MonitorConfig.builder(NAME_PREFIX + clientName + "-" + clientVersion).build()); }}}Copy the code

3.3 RateLimitingFilter

Com.net flix. Eureka. RateLimitingFilter, request through the filter. In “Eureka source code parsing — RateLimiter based on the token bucket algorithm” detailed parsing.

3.4 GzipEncodingEnforcingFilter

3.5 ServletContainer

Com. Sun. Jersey. Spi. Container. Servlet. ServletContainer, jersey MVC request filter.

• The Jersey MVC pattern is shown below:

  FROM Jersey Framework MVC
  
  

• At com.net flix. Eureka. Resources bag, have all had – Server Jersey Resource (the Controller).

• The filter configuration in web.xml is as follows:

  <filter> <filter-name>jersey</filter-name> <filter-class>com.sun.jersey.spi.container.servlet.ServletContainer</filter-class> <init-param> <param-name>com.sun.jersey.config.property.WebPageContentRegex</param-name> <param-value>/(flex|images|js|css|jsp)/.*</param-value> </init-param> <init-param> <param-name>com.sun.jersey.config.property.packages</param-name> <param-value>com.sun.jersey; com.netflix</param-value> </init-param> <! -- GZIP content encoding/decoding --> <init-param> <param-name>com.sun.jersey.spi.container.ContainerRequestFilters</param-name> <param-value>com.sun.jersey.api.container.filter.GZIPContentEncodingFilter</param-value> </init-param> <init-param> <param-name>com.sun.jersey.spi.container.ContainerResponseFilters</param-name> <param-value>com.sun.jersey.api.container.filter.GZIPContentEncodingFilter</param-value> </init-param> </filter> <filter-mapping> <filter-name>jersey</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>Copy the code

666. The eggs

Eureka-server startup complete!

Preparations are now complete for more interesting eureka-client/Eureka-Server interactions such as registration, renewal, cancellation, expiration, and so on.

Approach!

Fat friends, share a wave of friends can be good! ?