手写分布式配置中心（二）实现分布式配置中心的简单版本

这一篇文章比较简单，就是一个增删改查的服务端和一个获取配置的客户端，旨在搭建一个简单的配置中心架构，代码在 https://gitee.com/summer-cat001/config-center

服务端

服务端选择用springboot 2.7.14搭建，设计了4个接口/config/insert、/config/update、/config/delete、/config/get。

Controller层

Controller层做了请求参数的校验，和对服务层的转发

@RestController
@RequestMapping("/config")
public class ConfigController {@Autowiredprivate ConfigService configService;@PostMapping("/insert")public Result<Void> insertConfig(@RequestBody ConfigVO configVO) {Result<ConfigBO> result = checkOpConfig(configVO);if (result.failed()) {return Result.resultToFail(result);}return configService.insertConfig(result.getData());}@PostMapping("/update")public Result<Void> updateConfig(@RequestBody ConfigVO configVO) {Result<ConfigBO> result = checkOpConfig(configVO);if (result.failed()) {return Result.resultToFail(result);}ConfigBO configBO = result.getData();long id = configVO.getId();if (id <= 0) {return Result.fail("配置id错误");}configBO.setId(id);return configService.updateConfig(configBO);}@PostMapping("/delete")public Result<Void> delConfig(@RequestBody ConfigVO configVO) {long id = configVO.getId();if (id <= 0) {return Result.fail("配置id错误");}return configService.delConfig(id, 0L);}@GetMapping("/get")public Result<List<ConfigVO>> getAllValidConfig() {Result<List<ConfigBO>> result = configService.getAllValidConfig();if (result.failed()) {return Result.resultToFail(result);}return Result.success(result.getData().stream().map(configBO -> {ConfigVO configVO = new ConfigVO();configVO.setId(configBO.getId());configVO.setName(configBO.getName());configVO.setConfigData(configBO.getConfigData());configVO.setCreateTime(DateUtil.date2str1(configBO.getCreateTime()));return configVO;}).collect(Collectors.toList()));}private Result<ConfigBO> checkOpConfig(ConfigVO configVO) {String name = configVO.getName();if (name == null || (name = name.trim()).length() == 0) {return Result.fail("配置名不能为空");}JSONObject configData = configVO.getConfigData();if (configData == null) {return Result.fail("配置内容不能为空");}ConfigBO configBO = new ConfigBO();configBO.setName(name);configBO.setConfigData(configData);return Result.success(configBO);}
}

Service层

Service层做了数据的转换和对dao层的调用，对于这个配置中心数据的存储，我做了两个模式，1是单机模式，2是集群模式。简单的来说就是一个存在数据库中，一个存在本地。根据配置文件中的config.center.mode来指定使用哪种模式

@Service
public class ConfigServiceImpl implements ConfigService {private ConfigDAO configDAO;@Autowiredprivate LocalConfigDAO localConfigDAO;@Value("${config.center.mode:0}")private int configCenterMode;@PostConstructpublic void init() {ConfigCenterModeEnum configCenterModeEnum = ConfigCenterModeEnum.getEnum(configCenterMode);if (configCenterModeEnum == null) {throw new IllegalArgumentException("配置config.center.mode错误");}if (configCenterModeEnum == ConfigCenterModeEnum.STANDALONE) {this.configDAO = localConfigDAO;}}@Overridepublic Result<Void> insertConfig(ConfigBO configBO) {List<ConfigDO> configList = configDAO.getAllValidConfig();if (configList.stream().anyMatch(c -> c.getName().equals(configBO.getName()))) {return Result.fail("配置名重复");}ConfigDO configDO = new ConfigDO();configDO.setName(configBO.getName());configDO.setConfigData(configBO.getConfigData().toJSONString());configDAO.insertConfigDO(configDO);return Result.success(null);}@Overridepublic Result<Void> updateConfig(ConfigBO configBO) {ConfigDO configDO = new ConfigDO();configDO.setId(configBO.getId());configDO.setName(configBO.getName());configDO.setConfigData(configBO.getConfigData().toJSONString());configDAO.updateConfig(configDO);return Result.success(null);}@Overridepublic Result<Void> delConfig(long id, long updateUid) {configDAO.delConfig(id, updateUid);return Result.success(null);}@Overridepublic Result<List<ConfigBO>> getAllValidConfig() {List<ConfigDO> configList = configDAO.getAllValidConfig();return Result.success(configList.stream().map(configDO -> {ConfigBO configBO = new ConfigBO();configBO.setId(configDO.getId());configBO.setName(configDO.getName());configBO.setCreateTime(configDO.getCreateTime());configBO.setConfigData(JSON.parseObject(configDO.getConfigData()));return configBO;}).collect(Collectors.toList()));}
}

DAO层

DAO层提供了一个接口com.config.center.dao.ConfigDAO。单机和集群模式分别实现这个接口，例如单机模式是com.config.center.dao.impl.LocalConfigDAO实现类（集群模式就是访问数据库，大家估计都用吐了，这个就不多介绍了）。
单机模式就是将配置文件存储到本地的一个路径中，这个路径根据配置文件的config.center.standalone.path配置来指定，保存的是以配置id为文件名.conf为后缀的文件。其中id是从1开始自增，增加配置接口用了锁，所以id不会重复

@Slf4j
@Repository
public class LocalConfigDAO implements ConfigDAO {private final Lock insertLock = new ReentrantLock();@Value("${config.center.standalone.path}")private String standalonePath;@Overridepublic long insertConfigDO(ConfigDO configDO) {insertLock.lock();try {long id = 1;List<ConfigDO> configList = getAllConfig();if (!configList.isEmpty()) {id = configList.get(configList.size() - 1).getId() + 1;}configDO.setId(id);Optional.of(configDO).filter(c -> c.getCreateTime() == null).ifPresent(c -> c.setCreateTime(LocalDateTime.now()));String configPathStr = standalonePath + "/config";Files.createDirectories(Paths.get(configPathStr));Path path = Paths.get(configPathStr + "/" + id + ".conf");Files.write(path, JSON.toJSONString(configDO).getBytes(StandardCharsets.UTF_8), StandardOpenOption.CREATE_NEW);return id;} catch (Exception e) {throw new RuntimeException(e);} finally {insertLock.unlock();}}@Overridepublic void updateConfig(ConfigDO configDO) {ConfigDO dbConfigDO = getConfig(configDO.getId());Optional.ofNullable(dbConfigDO).map(c -> {c.setName(configDO.getName());c.setUpdateTime(LocalDateTime.now());c.setUpdateUid(configDO.getUpdateUid());c.setConfigData(configDO.getConfigData());return c;}).ifPresent(this::updateConfigDO);}@Overridepublic void delConfig(long id, long updateUid) {ConfigDO dbConfigDO = getConfig(id);Optional.ofNullable(dbConfigDO).map(c -> {c.setDeleted(true);c.setUpdateTime(LocalDateTime.now());c.setUpdateUid(updateUid);return c;}).ifPresent(this::updateConfigDO);}@Overridepublic ConfigDO getConfig(long id) {List<ConfigDO> configList = getAllConfig();return configList.stream().filter(c -> c.getId() == id).findFirst().orElse(null);}@Overridepublic List<ConfigDO> getAllValidConfig() {return getAllConfig().stream().filter(c -> !c.isDeleted()).collect(Collectors.toList());}@Overridepublic List<ConfigDO> getAllConfig() {File[] files;File folder = new File(standalonePath + "/config");if (!folder.exists() || (files = folder.listFiles()) == null) {return new ArrayList<>();}return Arrays.stream(files).map(File::getAbsolutePath).filter(p -> p.endsWith(".conf")).map(this::buildConfigDO).filter(Objects::nonNull).sorted(Comparator.comparing(ConfigDO::getId)).collect(Collectors.toList());}private synchronized ConfigDO buildConfigDO(String path) {try {byte[] bytes = Files.readAllBytes(Paths.get(path));String json = new String(bytes, StandardCharsets.UTF_8);return JSON.parseObject(json, ConfigDO.class);} catch (Exception e) {log.error("buildConfigDO error,path:{}", path, e);return null;}}private synchronized void updateConfigDO(ConfigDO configDO) {Path path = Paths.get(standalonePath + "/config/" + configDO.getId() + ".conf");if (Files.exists(path)) {try {Files.write(path, JSON.toJSONString(configDO).getBytes(StandardCharsets.UTF_8), StandardOpenOption.WRITE);} catch (IOException e) {log.error("updateConfigDO error configDO:{}", configDO, e);}}}
}

效果

到这里就已经完成了服务端的构建了，简单吧，下面看看效果

新增配置

获取所有有效配置

修改配置

删除配置

客户端

客户端就更简单了，就是在启动时通过http调用上面的/config/get接口获取配置，并且赋值给对象的成员变量，之后直接使用这个成员变量即可

public class ConfigCenterClient {/*** 服务端地址*/private String url;public List<ConfigVO> getAllValidConfig() {HttpRespBO httpRespBO = HttpUtil.httpGet(url + "/config/get");if (!httpRespBO.success()) {throw new IllegalArgumentException("获取配置失败：code:" + httpRespBO.getCode() + ",msg:" + httpRespBO.getMessage());}if (httpRespBO.getBody() == null) {throw new IllegalArgumentException("获取配置失败 body is null：code:" + httpRespBO.getCode() + ",msg:" + httpRespBO.getMessage());}Result<?> result = JSON.parseObject(new String(httpRespBO.getBody(), StandardCharsets.UTF_8), Result.class);if (result.failed()) {throw new IllegalArgumentException("获取配置失败 result:" + result);}return JSON.parseArray(JSON.toJSONString(result.getData()), ConfigVO.class);}public void setUrl(String url) {this.url = url;}}

public class ClientTest {private String userName;private String userAge;private List<Object> education;public ClientTest() {ConfigCenterClient configCenterClient = new ConfigCenterClient();configCenterClient.setUrl("http://localhost:8088");List<ConfigVO> configList = configCenterClient.getAllValidConfig();configList.stream().map(ConfigVO::getConfigData).map(c -> c.getJSONObject("user")).findFirst().ifPresent(user -> {this.userName = user.getString("name");this.userAge = user.getString("age");this.education = user.getJSONArray("education");});}public String toString() {return "姓名:" + userName + ",年龄:" + userAge + ",教育经历:" + education;}public static void main(String[] args) {ClientTest clientTest = new ClientTest();System.out.println(clientTest);}
}

这样整个配置中心的简单版本就完成了，不过这样只是在new对象的时候设置了配置的值，但是如果配置中心的配置发生变化后，客户端是无法感知的，为了解决这个问题需要加入配置自动刷新功能，这个我们在下一篇文章中介绍。