SpringBoot實現服務接入nacos註冊中心流程詳解
概述
某些場景下隻需要把springboot微服務化而不想引入springcloud如何實現的呢?
下面我們介紹nacos註冊中心方案。
接入nacos註冊中心
springboot服務pom文件
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>com.study</groupId> <artifactId>practice</artifactId> <version>1.0.0-SNAPSHOT</version> </parent> <artifactId>practice-demo</artifactId> <dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-dependencies</artifactId> <version>2.1.3.RELEASE</version> <type>pom</type> <scope>import</scope> </dependency> </dependencies> </dependencyManagement> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <java.version>1.8</java.version> </properties> <!-- springboot --> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> <exclusions> <exclusion> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-logging</artifactId> </exclusion> </exclusions> </dependency> <!--test --> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-log4j2</artifactId> </dependency> <!--nacos註冊中心--> <dependency> <groupId>com.alibaba.boot</groupId> <artifactId>nacos-discovery-spring-boot-starter</artifactId> <version>0.2.7</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> <version>2.1.3.RELEASE</version> <executions> <execution> <goals> <goal>repackage</goal> </goals> </execution> </executions> </plugin> </plugins> </build> </project>
application.properties配置
# nacos註冊
spring.application.name=file-server-service
nacos.discovery.server-addr=192.168.1.1:8848,192.168.1.2:8848
nacos.discovery.auto-register=true
nacos.discovery.enabled=true
# 指定微服務註冊那個地址
nacos.discovery.register.ip=
源碼分析
主流程:
1、nacos-discovery-spring-boot-starter 啟動服務通過SPI機制掃描到nacos-discovery-spring-boot-autoconfigure包。
2、nacos-discovery-spring-boot-autoconfigure項目通過自動裝配功能裝配nacos客戶端
3、 Nacos自動配置服務實現Spring的應用監聽器用來註冊nacos服務
NacosDiscoveryAutoRegister implements ApplicationListener
4、NacosDiscoveryAutoRegister監聽到spring的ServletWebServerInitializedEvent事件後把springboot服務註冊到nacos註冊中心
5、調用nacos-client jar包中的com.alibaba.nacos.client.naming.net.NamingProxy#registerService完成服務註冊
核心處理邏輯:com.alibaba.nacos.client.naming.net.NamingProxy.java
public String reqAPI(String api, Map<String, String> params, String body, List<String> servers, String method) throws NacosException { params.put("namespaceId", this.getNamespaceId()); if (CollectionUtils.isEmpty(servers) && StringUtils.isEmpty(this.nacosDomain)) { throw new NacosException(400, "no server available"); } else { NacosException exception = new NacosException(); // 如果nacos.discovery.server-addr是逗號分隔的列表走改分組 if (servers != null && !servers.isEmpty()) { Random random = new Random(System.currentTimeMillis()); int index = random.nextInt(servers.size()); int i = 0; while(i < servers.size()) { String server = (String)servers.get(index); try { return this.callServer(api, params, body, server, method); } catch (NacosException var13) { exception = var13; if (LogUtils.NAMING_LOGGER.isDebugEnabled()) { LogUtils.NAMING_LOGGER.debug("request {} failed.", server, var13); } index = (index + 1) % servers.size(); ++i; } } } // 如果nacos.discovery.server-addr隻配置一個服務地址而不是逗號分隔的多個服務地址 if (StringUtils.isNotBlank(this.nacosDomain)) { int i = 0; while(i < 3) { try { return this.callServer(api, params, body, this.nacosDomain, method); } catch (NacosException var12) { exception = var12; if (LogUtils.NAMING_LOGGER.isDebugEnabled()) { LogUtils.NAMING_LOGGER.debug("request {} failed.", this.nacosDomain, var12); } ++i; } } } ... } } /** 調用nacos服務器,把springboot服務註冊為微服務 使用服務註冊接口:http://xxx:xxx/nacos/v1/ns/instance **/ public String callServer(String api, Map<String, String> params, String body, String curServer, String method) throws NacosException { long start = System.currentTimeMillis(); long end = 0L; this.injectSecurityInfo(params); List<String> headers = this.builderHeaders(); String url; // 如果nacos.discovery.server-addr地址不是http://或者https://開頭走該分組 if (!curServer.startsWith("https://") && !curServer.startsWith("http://")) { // 如果隻寫瞭ip地址,會追加默認的8848端口 if (!curServer.contains(":")) { curServer = curServer + ":" + this.serverPort; } // 添加http前綴,http或者https,配置項com.alibaba.nacos.client.naming.tls.enable確定是http還是https url = HttpClient.getPrefix() + curServer + api; } else { url = curServer + api; } HttpResult result = HttpClient.request(url, headers, params, body, "UTF-8", method); end = System.currentTimeMillis(); MetricsMonitor.getNamingRequestMonitor(method, url, String.valueOf(result.code)).observe((double)(end - start)); if (200 == result.code) { return result.content; } else if (304 == result.code) { return ""; } else { throw new NacosException(result.code, result.content); } }
小結
nacos.discovery.server-addr配置項支持的方式:
單個ip:port形式
nacos.discovery.server-addr=192.168.10.18:8858
多個ip:port形式
nacos.discovery.server-addr=192.168.10.18:8858,192.168.10.19:8858
域名方式(http://或者https://開頭)
nacos.discovery.server-addr=https://www.xxx
從源碼我們可以看出,其實nacos.discovery.server-addr配置多個地址,nacos會隨機選擇一個服務器地址,如果註冊成功就返回瞭,不會去處理其他的服務地址,除非一個地址註冊失敗才會使用其他的地址註冊;nacos集群情況下,最好配置多個地址,放在一個nacos註冊失敗導致服務註冊不上的問題。
源碼流程圖
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