在進行多租戶架構(Multi-tenancy)實現之前,先了解一下相關的定義吧:
什么是多租戶
多租戶技術或稱多重租賃技術,簡稱SaaS
,是一種軟件架構技術,是實現如何在多用戶環境下(此處的多用戶一般是面向企業用戶)共用相同的系統或程序組件,并且可確保各用戶間數據的隔離性。
簡單講:在一臺服務器上運行單個應用實例,它為多個租戶(客戶)提供服務。從定義中我們可以理解:多租戶是一種架構,目的是為了讓多用戶環境下使用同一套程序,且保證用戶間數據隔離。那么重點就很淺顯易懂了,多租戶的重點就是同一套程序下實現多用戶數據的隔離。
數據隔離方案
多租戶在數據存儲上存在三種主要的方案,分別是:
獨立數據庫
即一個租戶一個數據庫,這種方案的用戶數據隔離級別最高,安全性最好,但成本較高。
優點:為不同的租戶提供獨立的數據庫,有助于簡化數據模型的擴展設計,滿足不同租戶的獨特需求;如果出現故障,恢復數據比較簡單。
缺點:增多了數據庫的安裝數量,隨之帶來維護成本和購置成本的增加。
共享數據庫,獨立 Schema
多個或所有租戶共享Database,但是每個租戶一個Schema(也可叫做一個user)。底層庫比如是:DB2、ORACLE等,一個數據庫下可以有多個SCHEMA。
優點:為安全性要求較高的租戶提供了一定程度的邏輯數據隔離,并不是完全隔離;每個數據庫可支持更多的租戶數量。
缺點:如果出現故障,數據恢復比較困難,因為恢復數據庫將牽涉到其他租戶的數據;
共享數據庫,共享 Schema,共享數據表
即租戶共享同一個Database、同一個Schema,但在表中增加TenantID多租戶的數據字段。這是共享程度最高、隔離級別最低的模式。
簡單來講,即每插入一條數據時都需要有一個客戶的標識。這樣才能在同一張表中區分出不同客戶的數據,這也是我們系統目前用到的(provider_id)
優點:三種方案比較,第三種方案的維護和購置成本最低,允許每個數據庫支持的租戶數量最多。
缺點:隔離級別最低,安全性最低,需要在設計開發時加大對安全的開發量;數據備份和恢復最困難,需要逐表逐條備份和還原。
利用MybatisPlus實現
這里我們選用了第三種方案(共享數據庫,共享 Schema,共享數據表
)來實現,也就意味著,每個數據表都需要有一個租戶標識(provider_id
)
現在有數據庫表(user
)如下:
將provider_id
視為租戶ID,用來隔離租戶與租戶之間的數據,如果要查詢當前服務商的用戶,SQL大致如下:
SELECT * FROM user t WHERE t.name LIKE '%Tom%' AND t.provider_id = 1;
試想一下,除了一些系統共用的表以外,其他租戶相關的表,我們都需要不厭其煩的加上AND t.provider_id = ?查詢條件,稍不注意就會導致數據越界,數據安全問題讓人擔憂。
好在有了MybatisPlus這個神器,可以極為方便的實現多租戶SQL解析器,官方文檔如下:
這里終于進入了正題,開始搭建一個極為簡單的開發環境吧!
新建SpringBoot環境
POM文件如下,主要集成了MybatisPlus以及H2數據庫(方便測試)
<?xml version="1.0" encoding="UTF-8"?>
<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>
<groupId>com.wuwenze</groupId>
<artifactId>mybatis-plus-multi-tenancy</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>mybatis-plus-multi-tenancy</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.0.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>com.google.guava</groupId>
<artifactId>guava</artifactId>
<version>19.0</version>
</dependency>
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>3.0.5</version>
</dependency>
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus</artifactId>
<version>3.0.5</version>
</dependency>
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-generator</artifactId>
<version>3.0.5</version>
</dependency>
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
數據源配置(application.yml)
spring:
datasource:
driver-class-name: org.h2.Driver
schema: classpath:db/schema.sql
data: classpath:db/data.sql
url: jdbc:h2:mem:test
username: root
password: test
logging:
level:
com.wuwenze.mybatisplusmultitenancy: debug
對應的H2數據庫初始化schema文件
#schema.sql
DROP TABLE IF EXISTS user;
CREATE TABLE user
(
id BIGINT(20) NOT NULL COMMENT '主鍵',
provider_id BIGINT(20) NOT NULL COMMENT '服務商ID',
name VARCHAR(30) NULL DEFAULT NULL COMMENT '姓名',
PRIMARY KEY (id)
);
#data.sql
INSERT INTO user (id, provider_id, name) VALUES (1, 1, 'Tony老師');
INSERT INTO user (id, provider_id, name) VALUES (2, 1, 'William老師');
INSERT INTO user (id, provider_id, name) VALUES (3, 2, '路人甲');
INSERT INTO user (id, provider_id, name) VALUES (4, 2, '路人乙');
INSERT INTO user (id, provider_id, name) VALUES (5, 2, '路人丙');
INSERT INTO user (id, provider_id, name) VALUES (6, 2, '路人丁');
MybatisPlus Config
基礎環境搭建完成,現在開始配置MybatisPlus多租戶相關的實現。
1) 核心配置:TenantSqlParser
@Configuration
@MapperScan("com.wuwenze.mybatisplusmultitenancy.mapper")
public class MybatisPlusConfig {
private static final String SYSTEM_TENANT_ID = "provider_id";
private static final List<String> IGNORE_TENANT_TABLES = Lists.newArrayList("provider");
@Autowired
private ApiContext apiContext;
@Bean
public PaginationInterceptor paginationInterceptor() {
PaginationInterceptor paginationInterceptor = new PaginationInterceptor();
// SQL解析處理攔截:增加租戶處理回調。
TenantSqlParser tenantSqlParser = new TenantSqlParser()
.setTenantHandler(new TenantHandler() {
@Override
public Expression getTenantId() {
// 從當前系統上下文中取出當前請求的服務商ID,通過解析器注入到SQL中。
Long currentProviderId = apiContext.getCurrentProviderId();
if (null == currentProviderId) {
throw new RuntimeException("#1129 getCurrentProviderId error.");
}
return new LongValue(currentProviderId);
}
@Override
public String getTenantIdColumn() {
return SYSTEM_TENANT_ID;
}
@Override
public boolean doTableFilter(String tableName) {
// 忽略掉一些表:如租戶表(provider)本身不需要執行這樣的處理。
return IGNORE_TENANT_TABLES.stream().anyMatch((e) -> e.equalsIgnoreCase(tableName));
}
});
paginationInterceptor.setSqlParserList(Lists.newArrayList(tenantSqlParser));
return paginationInterceptor;
}
@Bean(name = "performanceInterceptor")
public PerformanceInterceptor performanceInterceptor() {
return new PerformanceInterceptor();
}
}
2) ApiContext
@Component
public class ApiContext {
private static final String KEY_CURRENT_PROVIDER_ID = "KEY_CURRENT_PROVIDER_ID";
private static final Map<String, Object> mContext = Maps.newConcurrentMap();
public void setCurrentProviderId(Long providerId) {
mContext.put(KEY_CURRENT_PROVIDER_ID, providerId);
}
public Long getCurrentProviderId() {
return (Long) mContext.get(KEY_CURRENT_PROVIDER_ID);
}
}
3) Entity、Mapper
@Data
@ToString
@Accessors(chain = true)
public class User {
private Long id;
private Long providerId;
private String name;
}
public interface UserMapper extends BaseMapper<User> {
}
單元測試
com.wuwenze.mybatisplusmultitenancy.MybatisPlusMultiTenancyApplicationTests
@Slf4j
@RunWith(SpringRunner.class)
@FixMethodOrder(MethodSorters.JVM)
@SpringBootTest(classes = MybatisPlusMultiTenancyApplication.class)
public class MybatisPlusMultiTenancyApplicationTests {
@Autowired
private ApiContext apiContext;
@Autowired
private UserMapper userMapper;
@Before
public void before() {
// 在上下文中設置當前服務商的ID
apiContext.setCurrentProviderId(1L);
}
@Test
public void insert() {
User user = new User().setName("新來的Tom老師");
Assert.assertTrue(userMapper.insert(user) > 0);
user = userMapper.selectById(user.getId());
log.info("#insert user={}", user);
// 檢查插入的數據是否自動填充了租戶ID
Assert.assertEquals(apiContext.getCurrentProviderId(), user.getProviderId());
}
@Test
public void selectList() {
userMapper.selectList(null).forEach((e) -> {
log.info("#selectList, e={}", e);
// 驗證查詢的數據是否超出范圍
Assert.assertEquals(apiContext.getCurrentProviderId(), e.getProviderId());
});
}
}
運行結果
2018-11-29 21:07:14.262 INFO 18688 --- [ main] .MybatisPlusMultiTenancyApplicationTests : Started MybatisPlusMultiTenancyApplicationTests in 2.629 seconds (JVM running for 3.904)
2018-11-29 21:07:14.554 DEBUG 18688 --- [ main] c.w.m.mapper.UserMapper.insert : ==> Preparing: INSERT INTO user (id, name, provider_id) VALUES (?, ?, 1)
2018-11-29 21:07:14.577 DEBUG 18688 --- [ main] c.w.m.mapper.UserMapper.insert : ==> Parameters: 1068129257418178562(Long), 新來的Tom老師(String)
2018-11-29 21:07:14.577 DEBUG 18688 --- [ main] c.w.m.mapper.UserMapper.insert : <== Updates: 1
Time:0 ms - ID:com.wuwenze.mybatisplusmultitenancy.mapper.UserMapper.insert
Execute SQL:INSERT INTO user (id, name, provider_id) VALUES (?, ?, 1) {1: 1068129257418178562, 2: STRINGDECODE('\u65b0\u6765\u7684Tom\u8001\u5e08')}
2018-11-29 21:07:14.585 DEBUG 18688 --- [ main] c.w.m.mapper.UserMapper.selectById : ==> Preparing: SELECT id, provider_id, name FROM user WHERE user.provider_id = 1 AND id = ?
2018-11-29 21:07:14.595 DEBUG 18688 --- [ main] c.w.m.mapper.UserMapper.selectById : ==> Parameters: 1068129257418178562(Long)
2018-11-29 21:07:14.614 DEBUG 18688 --- [ main] c.w.m.mapper.UserMapper.selectById : <== Total: 1
2018-11-29 21:07:14.615 INFO 18688 --- [ main] .MybatisPlusMultiTenancyApplicationTests : #insert user=User(id=1068129257418178562, providerId=1, name=新來的Tom老師)
Time:19 ms - ID:com.wuwenze.mybatisplusmultitenancy.mapper.UserMapper.selectById
Execute SQL:SELECT id, provider_id, name FROM user WHERE user.provider_id = 1 AND id = ? {1: 1068129257418178562}
2018-11-29 21:07:14.626 DEBUG 18688 --- [ main] c.w.m.mapper.UserMapper.selectList : ==> Preparing: SELECT id, provider_id, name FROM user WHERE user.provider_id = 1
Time:0 ms - ID:com.wuwenze.mybatisplusmultitenancy.mapper.UserMapper.selectList
Execute SQL:SELECT id, provider_id, name FROM user WHERE user.provider_id = 1
2018-11-29 21:07:14.629 DEBUG 18688 --- [ main] c.w.m.mapper.UserMapper.selectList : ==> Parameters:
2018-11-29 21:07:14.630 DEBUG 18688 --- [ main] c.w.m.mapper.UserMapper.selectList : <== Total: 3
2018-11-29 21:07:14.632 INFO 18688 --- [ main] .MybatisPlusMultiTenancyApplicationTests : #selectList, e=User(id=1, providerId=1, name=Tony老師)
2018-11-29 21:07:14.632 INFO 18688 --- [ main] .MybatisPlusMultiTenancyApplicationTests : #selectList, e=User(id=2, providerId=1, name=William老師)
2018-11-29 21:07:14.632 INFO 18688 --- [ main] .MybatisPlusMultiTenancyApplicationTests : #selectList, e=User(id=1068129257418178562, providerId=1, name=新來的Tom老師)
從打印的日志不難看出,這個方案相當完美,僅需簡單的配置,讓開發者完全忽略了(provider_id)字段的存在,同時又最大程度的保證了數據的安全性,可謂是一舉兩得!