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KV存储与配置管理

Salmon2026/1/15大约 4 分钟ConsulKV存储配置中心

KV 存储与配置管理

一、KV 存储概述

Consul 提供分布式 Key-Value 存储，可用于：

  • 动态配置管理
  • 特性开关
  • 服务协调
  • Leader 选举

1.1 KV 存储特点

二、基本操作

2.1 命令行操作

# 写入键值
consul kv put config/database/host 192.168.1.100
consul kv put config/database/port 3306

# 读取键值
consul kv get config/database/host

# 读取所有键
consul kv get -recurse config/

# 删除键值
consul kv delete config/database/host

# 删除前缀下所有键
consul kv delete -recurse config/database/

2.2 HTTP API 操作

# 写入
curl -X PUT -d "192.168.1.100" http://localhost:8500/v1/kv/config/database/host

# 读取
curl http://localhost:8500/v1/kv/config/database/host

# 读取并解码
curl -s http://localhost:8500/v1/kv/config/database/host | jq -r '.[0].Value' | base64 -d

# 列出所有键
curl "http://localhost:8500/v1/kv/config/?keys"

# 递归读取
curl "http://localhost:8500/v1/kv/config/?recurse"

# 删除
curl -X DELETE http://localhost:8500/v1/kv/config/database/host

2.3 响应格式

[
  {
    "LockIndex": 0,
    "Key": "config/database/host",
    "Flags": 0,
    "Value": "MTkyLjE2OC4xLjEwMA==",
    "CreateIndex": 100,
    "ModifyIndex": 200
  }
]

三、配置管理

3.1 配置结构设计

config/
├── common/                 # 公共配置
│   ├── database
│   └── redis
├── user-service/          # 服务专属配置
│   ├── application.yml
│   └── feature-flags
└── order-service/
    ├── application.yml
    └── feature-flags

3.2 存储 YAML 配置

# 存储配置文件
consul kv put config/user-service/application.yml @application.yml

# 或直接写入
consul kv put config/user-service/data '
server:
  port: 8080
spring:
  datasource:
    url: jdbc:mysql://localhost:3306/user
    username: root
    password: secret
'

3.3 存储 JSON 配置

consul kv put config/user-service/settings '{
  "maxConnections": 100,
  "timeout": 30,
  "retryCount": 3
}'

四、Spring Cloud Consul Config

4.1 添加依赖

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-consul-config</artifactId>
</dependency>

4.2 配置文件

# bootstrap.yml
spring:
  application:
    name: user-service
  profiles:
    active: dev
  cloud:
    consul:
      host: localhost
      port: 8500
      config:
        enabled: true
        format: YAML
        prefix: config
        default-context: application
        profile-separator: ','
        data-key: data

4.3 配置加载顺序

4.4 在 Consul 中存储配置

# 应用配置
consul kv put config/user-service/data '
server:
  port: 8080
custom:
  message: Hello from Consul
'

# 环境配置
consul kv put config/user-service,dev/data '
custom:
  message: Hello from Dev
'

4.5 使用配置

@RestController
@RefreshScope
public class ConfigController {
    
    @Value("${custom.message}")
    private String message;
    
    @GetMapping("/config")
    public String getConfig() {
        return message;
    }
}

五、配置动态刷新

5.1 启用 Watch

spring:
  cloud:
    consul:
      config:
        watch:
          enabled: true
          delay: 1000  # 检查间隔（毫秒）

5.2 使用 @RefreshScope

@Configuration
@RefreshScope
public class DynamicConfig {
    
    @Value("${feature.newUI:false}")
    private boolean newUIEnabled;
    
    @Value("${rate.limit:100}")
    private int rateLimit;
    
    public boolean isNewUIEnabled() {
        return newUIEnabled;
    }
    
    public int getRateLimit() {
        return rateLimit;
    }
}

5.3 监听配置变更

@Component
public class ConfigChangeListener implements ApplicationListener<RefreshScopeRefreshedEvent> {
    
    @Override
    public void onApplicationEvent(RefreshScopeRefreshedEvent event) {
        System.out.println("Configuration refreshed!");
        // 执行配置变更后的逻辑
    }
}

六、Watch 机制

6.1 HTTP 长轮询

# 阻塞查询，等待变更
curl "http://localhost:8500/v1/kv/config/user-service/data?index=100&wait=5m"

6.2 Java Watch 实现

@Component
public class ConsulKVWatcher {
    
    private final ConsulClient consulClient;
    private final ExecutorService executor = Executors.newSingleThreadExecutor();
    
    public ConsulKVWatcher(ConsulClient consulClient) {
        this.consulClient = consulClient;
    }
    
    @PostConstruct
    public void startWatch() {
        executor.submit(() -> {
            long index = 0;
            while (true) {
                try {
                    Response<GetValue> response = consulClient.getKVValue(
                        "config/user-service/data",
                        new QueryParams(300, index)  // 5分钟超时
                    );
                    
                    if (response.getConsulIndex() != index) {
                        index = response.getConsulIndex();
                        String value = new String(Base64.getDecoder().decode(
                            response.getValue().getValue()
                        ));
                        onConfigChange(value);
                    }
                } catch (Exception e) {
                    Thread.sleep(5000);
                }
            }
        });
    }
    
    private void onConfigChange(String newConfig) {
        System.out.println("Config changed: " + newConfig);
    }
}

七、事务操作

7.1 CAS 操作

# 条件更新（只有 ModifyIndex 匹配时才更新）
curl -X PUT -d "new-value" "http://localhost:8500/v1/kv/config/key?cas=200"

7.2 事务 API

curl -X PUT http://localhost:8500/v1/txn \
  -d '[
    {
      "KV": {
        "Verb": "set",
        "Key": "config/key1",
        "Value": "dmFsdWUx"
      }
    },
    {
      "KV": {
        "Verb": "set",
        "Key": "config/key2",
        "Value": "dmFsdWUy"
      }
    }
  ]'

7.3 事务操作类型

Verb说明
set设置键值
get获取键值
delete删除键
cas条件设置
lock获取锁
unlock释放锁

八、分布式锁

8.1 获取锁

# 创建 Session
SESSION=$(curl -X PUT -d '{"Name": "my-lock", "TTL": "30s"}' \
  http://localhost:8500/v1/session/create | jq -r '.ID')

# 获取锁
curl -X PUT "http://localhost:8500/v1/kv/locks/my-resource?acquire=$SESSION"

8.2 释放锁

# 释放锁
curl -X PUT "http://localhost:8500/v1/kv/locks/my-resource?release=$SESSION"

# 销毁 Session
curl -X PUT "http://localhost:8500/v1/session/destroy/$SESSION"

8.3 Java 分布式锁

@Component
public class ConsulDistributedLock {
    
    private final ConsulClient consulClient;
    
    public ConsulDistributedLock(ConsulClient consulClient) {
        this.consulClient = consulClient;
    }
    
    public String acquireLock(String lockKey, int ttlSeconds) {
        // 创建 Session
        NewSession session = new NewSession();
        session.setName(lockKey);
        session.setTtl(ttlSeconds + "s");
        session.setBehavior(Session.Behavior.DELETE);
        
        String sessionId = consulClient.sessionCreate(session, null)
            .getValue();
        
        // 尝试获取锁
        boolean acquired = consulClient.setKVValue(
            "locks/" + lockKey,
            "locked",
            new PutParams().setAcquireSession(sessionId)
        ).getValue();
        
        if (acquired) {
            return sessionId;
        }
        
        // 获取失败，销毁 Session
        consulClient.sessionDestroy(sessionId, null);
        return null;
    }
    
    public void releaseLock(String lockKey, String sessionId) {
        consulClient.setKVValue(
            "locks/" + lockKey,
            "unlocked",
            new PutParams().setReleaseSession(sessionId)
        );
        consulClient.sessionDestroy(sessionId, null);
    }
}

九、特性开关

9.1 配置特性开关

consul kv put config/features/new-checkout true
consul kv put config/features/dark-mode false
consul kv put config/features/beta-users '["user1","user2"]'

9.2 Java 实现

@Component
@RefreshScope
public class FeatureFlags {
    
    @Value("${features.new-checkout:false}")
    private boolean newCheckout;
    
    @Value("${features.dark-mode:false}")
    private boolean darkMode;
    
    public boolean isNewCheckoutEnabled() {
        return newCheckout;
    }
    
    public boolean isDarkModeEnabled() {
        return darkMode;
    }
}

@RestController
public class FeatureController {
    
    @Autowired
    private FeatureFlags featureFlags;
    
    @GetMapping("/checkout")
    public String checkout() {
        if (featureFlags.isNewCheckoutEnabled()) {
            return "New checkout flow";
        }
        return "Legacy checkout flow";
    }
}

十、最佳实践

10.1 键命名规范

{环境}/{服务名}/{配置类型}/{配置项}

示例：
prod/user-service/database/host
dev/order-service/redis/port

10.2 配置版本管理

# 带版本的配置
consul kv put config/user-service/v1/data @config-v1.yml
consul kv put config/user-service/v2/data @config-v2.yml

# 当前版本指针
consul kv put config/user-service/current v2

10.3 敏感配置加密

@Configuration
public class EncryptedConfigProcessor {
    
    @Value("${encryption.key}")
    private String encryptionKey;
    
    public String decrypt(String encryptedValue) {
        // 使用 AES 解密
        return AESUtil.decrypt(encryptedValue, encryptionKey);
    }
}

十一、总结

最近更新:
贡献者: Salmon