多租户适配

需要从产品底层进行尽量少的改造，能够满足上云之后多租户的数据、缓存、定时任务等隔离

多租户适配条目

1. 持久层适配

考虑到产品业务的实际情况，要求数据源同时支持schema隔离和字段隔离，持久层的多租户适配业务代码需要零感知、无侵入，适配实现过程如下：

STEP-1. 表结构改造，追加租户字段、有预置脚本的表，需要跟租户字段建立联合主键；
STEP-2. 引入动态数据源，动态数据源查询租户信息，切换schema实现租户按schema隔离；
STEP-3. 改造dao，采用cglib加入Interceptor，在dao层方法的执> 行前加入拦截；
STEP-4. 用jsqlParser编写sql解析类，第3步拦截到的sql追加租户ID的条件；

动态数据源关键代码

获取租户信息中的schema信息，根据schema信息切换，租户信息通过rest接口获取，考虑了到性能已加ThreadLocal和redis两重缓存

protected Connection changeCatalog(Connection con) throws SQLException {
        String tenantId = InvocationInfoProxy.getTenantid();
        if (StringUtils.isBlank(tenantId)) {
            tenantId = "tenant";
        }
        String catalog = this.getCatalog(tenantId);
        if (StringUtils.isNotBlank(catalog)) {
            try {
                con.setCatalog(catalog);
            } catch (SQLException e) {
                logger.error("Error occurred when setting catalog for connection, Tenant ID is {}", tenantId);
                con.close();
                throw e;
            }
        } else {
//            logger.error("Switching catalog failed, check tenant ID -> {}!", tenantId);
            String defaultCatalog = PropertyUtil.getPropertyByKey("jdbc.catalog");
            if (StringUtils.isNotBlank(defaultCatalog) && !defaultCatalog.equals(con.getCatalog())) {
                con.setCatalog(defaultCatalog);
                logger.info("reset catalog for connection success!");
            }
        }
        return con;
    }

dao层改造关键代码

通过cglib代理的方式改造dao层，业务代码对租户隔离零感知

protected MdmJdbcPersistenceManager createPersistenceManager() throws DbException {
        if (this.manager == null) {
            try {
                this.lock.lock();
                if (this.manager == null) {
                    MdmJdbcSession jdbcSession = ProxyFactory.getProxy(
                            MdmJdbcSession.class,
                        new Class[]{JdbcTemplate.class, DBMetaHelper.class},
                        new Object[] {jdbcTemplate, dbMetaHelper},
                        new MdmJdbcPersistenceFilter(),
                        //0 无操作
                        NoOp.INSTANCE,
                        // 执行SQL
                        new ExecuteInterceptor(jdbcTemplate, dbMetaHelper));
                    manager = new MdmJdbcPersistenceManager(jdbcTemplate, dbMetaHelper, jdbcSession);
                }
            } finally {
                this.lock.unlock();
            }
        }
        return (MdmJdbcPersistenceManager) this.manager;
    }

Interceptor 关键代码

@Override
    public Object intercept(Object o, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable {
        List<String> sqlList = new ArrayList<>();
        try {
            if (objects[SQL_INDEX] instanceof String) {
                sqlList = Collections.singletonList(String.valueOf(objects[SQL_INDEX]));
            } else if (objects[SQL_INDEX] instanceof List) {
                sqlList = (List<String>) objects[SQL_INDEX];
            }
        } catch (Exception e) {
            logger.error("Errors occurred when extract sql from jdbc session, details:" + e.getMessage(), e);
        }
        if (CollectionUtils.isNotEmpty(sqlList)) {
            List<String> processedSqlList = MdmSQLParser.process(sqlList);
            if (CollectionUtils.isNotEmpty(processedSqlList)) {
                if (objects[SQL_INDEX] instanceof String) {
                    objects[SQL_INDEX] = processedSqlList.get(0);
                } else if (objects[SQL_INDEX] instanceof List) {
                    objects[SQL_INDEX] = processedSqlList;
                }
            }
        }
        return methodProxy.invokeSuper(o, objects);

    }

sqlParser关键代码

采用jSqlParser解析sql语句,并拼接租户id的条件,sql语法解析会消耗部分性能,为了提高性能加入了缓存

public static String parseAndProcess(String oldSql) throws Exception {
        String cacheSql = getCache(oldSql);
        if(!CommonUtils.isNULL(cacheSql)) {
            return cacheSql;
        }
        Statement stmt = CCJSqlParserUtil.parse(oldSql);
        if (stmt instanceof Select) {
            Select select = (Select) stmt;
            logger.debug("select-sql处理前：" + select);
            //检查、处理select
            checkAndHandleSelectBody(select.getSelectBody());
            logger.debug("select-sql处理后：" + select);

        } else if (stmt instanceof Insert){
            Insert insert = (Insert) stmt;
            logger.debug("insert-sql处理前：" + stmt);
            processInsert(insert);
            logger.debug("insert-sql处理后：" + stmt);
        } else if (stmt instanceof Update) {
            Update update = (Update) stmt;
            logger.debug("update-sql处理前：" + stmt);
            processUpdate(update);
            logger.debug("update-sql处理后：" + stmt);
        } else if (stmt instanceof Delete) {
            Delete delete = (Delete) stmt;
            logger.debug("delete-sql处理前：" + stmt);
            processDelete(delete);
            logger.debug("delete-sql处理后：" + stmt);
        }
        //其他形式语句暂不处理
        putCache(oldSql, stmt.toString());
        return stmt.toString();
    }

2. 定时任务适配

通过租户开通的回调函数，在其中通过消息驱动的方式，在主数据实例中通过消费方式，来给租户启动定时任务，租户的id即为定时任务的JobGroup，这样job在执行业务逻辑时，可以通过JobGroup获取租户信息，以下代码是通过redis发布订阅方式实现，也可以通过mq实现

final JedisPubSub jedisPubSub = new JedisPubSub() {
            @SuppressWarnings("unchecked")
            @Override
            public void onMessage(String channel, String message) {
                try {
                    if (CHANNEL.equals(channel) && StringUtils.isNotBlank(message.trim())) {
                        channelMessage[0] = message;
                        InvocationInfoProxy.setTenantid(message);
                        //数据统计的定时任务
                        String statisticJobGroup = STATISTIC_ANALYSIS_JOB_GROUP;
                        String statisticIdleJobName = "jobDetailStatisticAnalysisBgJob";
                        String statisticIdleJobNameByDayJobName = "jobDetailStatisticAnalysisByDayBgJob";
                        if (!QuartzManager.checkExists(statisticJobGroup, statisticIdleJobName)) {
                            Class idleClazz = Class.forName("com.yonyou.iuapmdm.scheduleJob.task.StatisticAnalysisBgJob");
                            //"0 30 1,12 * * ?"
                            String idleCronExp = AppUtils.getPropertyValue(APPLICATION_PROPERTIES, "idleCronExp");
                            QuartzManager.addJob(statisticJobGroup, statisticIdleJobName, idleClazz, null, idleCronExp);
                        }
                        if (!QuartzManager.checkExists(statisticJobGroup, statisticIdleJobNameByDayJobName)) {
                            Class byDayClazz = Class.forName("com.yonyou.iuapmdm.scheduleJob.task.StatisticAnalysisByDayBgJob");
                            //"0 0 1 * * ?"
                            String byDayCronExp = AppUtils.getPropertyValue(APPLICATION_PROPERTIES, "byDayCronExp");
                            QuartzManager.addJob(statisticJobGroup, statisticIdleJobNameByDayJobName, byDayClazz, null, byDayCronExp);
                        }
                        //标签过期扫描定时任务
                        String tagExpireScanJobGroup = TAG_EXPIRE_SCAN_JOB_GROUP;
                        String tagExpireScanJobName = "jobDetailTagExpireScanBgJob";
                        if (!QuartzManager.checkExists(tagExpireScanJobGroup, tagExpireScanJobName)) {
                            Class expireScanClz = Class.forName("com.yonyou.iuapmdm.scheduleJob.task.TagExpireScanBgJob");
                            //"0 0 * * * ?" 每一小时执行一次
                            String expireScanCronExp = AppUtils.getPropertyValue(APPLICATION_PROPERTIES, "tagExpireScanCronExp");
                            QuartzManager.addJob(tagExpireScanJobGroup, tagExpireScanJobName, expireScanClz, null, expireScanCronExp);
                        }
                    }
                } catch (Exception e) {
                    logger.error("Error occurred adding statistic analysis job, details:" + e.getMessage(), e);
                }
            }
        };
        Thread daemon = new Thread(() -> {
            MdmCacheManager.getInstance().subscribe(jedisPubSub, CHANNEL);
        });

3.redis缓存适配

比较简单，构造key的时候体现tenantId即可

private String buildKey(String key) {
        String tenantId = InvocationInfoProxy.getTenantid();
        if (StringUtils.isBlank(tenantId)) {
            tenantId = "tenant";
        }
        return StringUtils.join(new String[]{tenantId, key}, ":");
    }

4.websocket场景

从WebSocketSession中获取cookie信息，设置上下文即可

• 参考：https://www.jianshu.com/p/8beb7247b074