rocketmq-streams的ILeaseService使用示例详解

Vera ·
更新时间:2024-11-13
· 1971 次阅读

目录

ILeaseService

BasedLesaseImpl

ApplyTask

tryGetLease

LeaseServiceImpl

ILeaseStorage

DBLeaseStorage

小结

本文主要研究一下rocketmq-streams的ILeaseService

ILeaseService /** * 通过db实现租约和锁,可以更轻量级,减少其他中间件的依赖 使用主备场景,只有一个实例运行,当当前实例挂掉,在一定时间内,会被其他实例接手 也可以用于全局锁 */ public interface ILeaseService { /** * 默认锁定时间 */ static final int DEFALUT_LOCK_TIME = 60 * 5; /** * 检查某用户当前时间是否具有租约。这个方法是纯内存操作,无性能开销 * * @return true,租约有效;false,租约无效 */ boolean hasLease(String name); /** * 申请租约,会启动一个线程,不停申请租约,直到申请成功。 申请成功后,每 租期/2 续约。 如果目前被其他租户获取租约,只有在对方租约失效,后才允许新的租户获取租约 * * @param name 租约名称,无特殊要求,相同名称会竞争租约 */ void startLeaseTask(String name); /** * 申请租约,会启动一个线程,不停申请租约,直到申请成功。 申请成功后,每 租期/2 续约。 如果目前被其他租户获取租约,只有在对方租约失效,后才允许新的租户获取租约 * * @param name 租约名称,无特殊要求,相同名称会竞争租约 * @param callback 当第一获取租约时,回调此函数 */ void startLeaseTask(final String name, ILeaseGetCallback callback); /** * 申请租约,会启动一个线程,不停申请租约,直到申请成功。 申请成功后,每 租期/2 续约。 如果目前被其他租户获取租约,只有在对方租约失效,后才允许新的租户获取租约 * * @param name 租约名称,无特殊要求,相同名称会竞争租约 * @param leaseTermSecond 租期,在租期内可以做业务处理,单位是秒 * @param callback 当第一获取租约时,回调此函数 */ void startLeaseTask(final String name, int leaseTermSecond, ILeaseGetCallback callback); /** * 申请锁,无论成功与否,立刻返回。如果不释放,最大锁定时间是5分钟 * * @param name 业务名称 * @param lockerName 锁名称 * @return 是否枷锁成功 */ boolean lock(String name, String lockerName); /** * 申请锁,无论成功与否,立刻返回。默认锁定时间是5分钟 * * @param name 业务名称 * @param lockerName 锁名称 * @param lockTimeSecond 如果不释放,锁定的最大时间,单位是秒 * @return 是否枷锁成功 * @return */ boolean lock(String name, String lockerName, int lockTimeSecond); /** * 申请锁,如果没有则等待,等待时间可以指定,如果是-1 则无限等待。如果不释放,最大锁定时间是5分钟 * * @param name 业务名称 * @param lockerName 锁名称 * @param waitTime 没获取锁时,最大等待多长时间,如果是-1 则无限等待 * @return 是否枷锁成功 */ boolean tryLocker(String name, String lockerName, long waitTime); /** * 申请锁,如果没有则等待,等待时间可以指定,如果是-1 则无限等待。如果不释放,最大锁定时间是lockTimeSecond * * @param name 业务名称 * @param lockerName 锁名称 * @param waitTime 没获取锁时,最大等待多长时间,如果是-1 则无限等待 * @param lockTimeSecond 如果不释放,锁定的最大时间,单位是秒 * @return 是否枷锁成功 */ boolean tryLocker(String name, String lockerName, long waitTime, int lockTimeSecond); /** * 释放锁 * * @param name * @param lockerName * @return */ boolean unlock(String name, String lockerName); /** * 对于已经获取锁的,可以通过这个方法,一直持有锁。 和租约的区别是,当释放锁后,无其他实例抢占。无法实现主备模式 * * @param name 业务名称 * @param lockerName 锁名称 * @param lockTimeSecond 租期,这个方法会自动续约,如果不主动释放,会一直持有锁 * @return 是否成功获取锁 */ boolean holdLock(String name, String lockerName, int lockTimeSecond); /** * 是否持有锁,不会申请锁。如果以前申请过,且未过期,返回true,否则返回false * * @param name 业务名称 * @param lockerName 锁名称 * @return */ boolean hasHoldLock(String name, String lockerName); List<LeaseInfo> queryLockedInstanceByNamePrefix(String name, String lockerNamePrefix); }

ILeaseService接口定义了hasLease、startLeaseTask、lock、tryLocker、unlock、holdLock、hasHoldLock、queryLockedInstanceByNamePrefix方法

BasedLesaseImpl public abstract class BasedLesaseImpl implements ILeaseService { private static final Log LOG = LogFactory.getLog(BasedLesaseImpl.class); private static final String CONSISTENT_HASH_PREFIX = "consistent_hash_"; private static final AtomicBoolean syncStart = new AtomicBoolean(false); private static final int synTime = 120; // 5分钟的一致性hash同步时间太久了,改为2分钟 protected ScheduledExecutorService taskExecutor = null; protected int leaseTerm = 300 * 2; // 租约时间 // protected transient JDBCDriver jdbcDataSource = null; protected ILeaseStorage leaseStorage; protected volatile Map<String, Date> leaseName2Date = new ConcurrentHashMap<>(); // 每个lease name对应的租约到期时间 public BasedLesaseImpl() { taskExecutor = new ScheduledThreadPoolExecutor(10); } /** * lease_name: consistent_hash_ip, lease_user_ip: ip,定时刷新lease_info表,检查一致性hash环的节点情况 * * @param name * @return */ @Override public boolean hasLease(String name) { // 内存中没有租约信息则表示 没有租约 Date leaseEndTime = leaseName2Date.get(name); if (leaseEndTime == null) { // LOG.info("内存中根据 " + name + "没有查询到租约信息,表示没有租约"); return false; } // LOG.info("查询是否有租约 name:" + name + " ,当前时间:" + new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()) // + " 租约到期时间 " + new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(leaseEndTime)); // 有租约时间,并且租约时间大于当前时间,表示有租约信息 if (new Date().before(leaseEndTime)) { return true; } return false; } private final Map<String, AtomicBoolean> startLeaseMap = new HashMap<>(); @Override public void startLeaseTask(final String name) { startLeaseTask(name, this.leaseTerm, null); } @Override public void startLeaseTask(final String name, ILeaseGetCallback callback) { startLeaseTask(name, this.leaseTerm, callback); } @Override public void startLeaseTask(final String name, int leaseTerm, ILeaseGetCallback callback) { ApplyTask applyTask = new ApplyTask(leaseTerm, name, callback); startLeaseTask(name, applyTask, leaseTerm / 2, true); } /** * 启动定时器,定时执行任务,确保任务可重入 * * @param name * @param runnable 具体任务 * @param scheduleTime 调度时间 * @param startNow 是否立刻启动一次 */ protected void startLeaseTask(final String name, Runnable runnable, int scheduleTime, boolean startNow) { AtomicBoolean isStartLease = startLeaseMap.get(name);//多次调用,只启动一次定时任务 if (isStartLease == null) { synchronized (this) { isStartLease = startLeaseMap.get(name); if (isStartLease == null) { isStartLease = new AtomicBoolean(false); startLeaseMap.put(name, isStartLease); } } } if (isStartLease.compareAndSet(false, true)) { if (startNow) { runnable.run(); } taskExecutor.scheduleWithFixedDelay(runnable, 0, scheduleTime, TimeUnit.SECONDS); } } //...... }

BasedLesaseImpl声明实现了ILeaseService,它依赖ILeaseStorage,startLeaseTask方法会创建ApplyTask,然后以固定间隔调度执行

ApplyTask /** * 续约任务 */ protected class ApplyTask implements Runnable { protected String name; protected int leaseTerm; protected ILeaseGetCallback callback; public ApplyTask(int leaseTerm, String name) { this(leaseTerm, name, null); } public ApplyTask(int leaseTerm, String name, ILeaseGetCallback callback) { this.name = name; this.leaseTerm = leaseTerm; this.callback = callback; } @Override public void run() { try { // LOG.info("LeaseServiceImpl name: " + name + "开始获取租约..."); AtomicBoolean newApplyLease = new AtomicBoolean(false); Date leaseDate = applyLeaseTask(leaseTerm, name, newApplyLease); if (leaseDate != null) { leaseName2Date.put(name, leaseDate); LOG.info("LeaseServiceImpl, name: " + name + " " + getSelfUser() + " 获取租约成功, 租约到期时间为 " + new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(leaseDate)); } else { // fix.2020.08.13 这时name对应的租约可能还在有效期内,或者本机还持有租约,需要remove // leaseName2Date.remove(name); LOG.info("LeaseServiceImpl name: " + name + " " + getSelfUser() + " 获取租约失败 "); } if (newApplyLease.get() &amp;&amp; callback != null) { callback.callback(leaseDate); } } catch (Exception e) { LOG.error(" LeaseServiceImpl name: " + name + " " + getSelfUser() + " 获取租约出现异常 ", e); } } } /** * 申请租约,如果当期租约有效,直接更新一个租约周期,如果当前租约无效,先查询是否有有效的租约,如果有申请失败,否则直接申请租约 */ protected Date applyLeaseTask(int leaseTerm, String name, AtomicBoolean newApplyLease) { // 计算下一次租约时间 = 当前时间 + 租约时长 Date nextLeaseDate = DateUtil.addSecond(new Date(), leaseTerm); // 1 如果已经有租约,则更新租约时间(内存和数据库)即可 if (hasLease(name)) { // LOG.info("用户已有租约,更新数据库和内存中的租约信息"); // 更新数据库 LeaseInfo leaseInfo = queryValidateLease(name); if (leaseInfo == null) { LOG.error("LeaseServiceImpl applyLeaseTask leaseInfo is null"); return null; } // fix.2020.08.13,与本机ip相等且满足一致性hash分配策略,才续约,其他情况为null String leaseUserIp = leaseInfo.getLeaseUserIp(); if (!leaseUserIp.equals(getSelfUser())) { return null; } leaseInfo.setLeaseEndDate(nextLeaseDate); updateLeaseInfo(leaseInfo); return nextLeaseDate; } // 2 没有租约情况 判断是否可以获取租约,只要租约没有被其他人获取,则说明有有效租约 boolean success = canGetLease(name); if (!success) { // 表示被其他机器获取到了有效的租约 // LOG.info("其他机器获取到了有效的租约"); return null; } // 3 没有租约而且可以获取租约的情况,则尝试使用数据库原子更新的方式获取租约,保证只有一台机器成功获取租约,而且可以运行 boolean flag = tryGetLease(name, nextLeaseDate); if (flag) { // 获取租约成功 newApplyLease.set(true); return nextLeaseDate; } return null; }

ApplyTask内部调用applyLeaseTask,如果已有租约则更新租约时间,没有租约则判断是否可以获取租约,可以则执行tryGetLease

tryGetLease /** * 更新数据库,占用租期并更新租期时间 * * @param time */ protected boolean tryGetLease(String name, Date time) { // LOG.info("尝试获取租约 lease name is : " + name + " 下次到期时间: " // + new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(time)); LeaseInfo validateLeaseInfo = queryValidateLease(name); if (validateLeaseInfo == null) {// 这里有两种情况 1 数据库里面没有租约信息 2 数据库里面有租约信息但是已经过期 Integer count = countLeaseInfo(name); if (count == null || count == 0) {// 表示现在数据库里面没有任何租约信息,插入租约成功则表示获取成功,失败表示在这一时刻其他机器获取了租约 // LOG.info("数据库中暂时没有租约信息,尝试原子插入租约:" + name); // fix.2020.08.13,经过一致性hash计算,该名字的任务不应该在本机执行,直接返回,无需插入。只有分配到hash执行权限的机器才可以插入并获取租约 if (!getSelfUser().equals(getConsistentHashHost(name))) { return false; } validateLeaseInfo = new LeaseInfo(); validateLeaseInfo.setLeaseName(name); validateLeaseInfo.setLeaseUserIp(getSelfUser()); validateLeaseInfo.setLeaseEndDate(time); validateLeaseInfo.setStatus(1); validateLeaseInfo.setVersion(1); if (insert(validateLeaseInfo)) { LOG.info("数据库中暂时没有租约信息,原子插入成功,获取租约成功:" + name); return true; } else { LOG.info("数据库中暂时没有租约信息,原子插入失败,已经被其他机器获取租约:" + name); return false; } } else { // 表示数据库里面有一条但是无效,这里需要两台机器按照version进行原子更新,更新成功的获取租约 // LOG.info("数据库中有一条无效的租约信息,尝试根据版本号去原子更新租约信息:" + name); LeaseInfo inValidateLeaseInfo = queryInValidateLease(name); if (inValidateLeaseInfo == null) {// 说明这个时候另外一台机器获取成功了 LOG.info("另外一台机器获取成功了租约:" + name); return false; } // fix.2020.08.13,机器重启之后,该名字的任务已经不分配在此机器上执行,直接返回,无需更新数据库 if (!getSelfUser().equals(getConsistentHashHost(name))) { return false; } inValidateLeaseInfo.setLeaseName(name); inValidateLeaseInfo.setLeaseUserIp(getSelfUser()); inValidateLeaseInfo.setLeaseEndDate(time); inValidateLeaseInfo.setStatus(1); boolean success = updateDBLeaseInfo(inValidateLeaseInfo); if (success) { LOG.info("LeaseServiceImpl 原子更新租约成功,当前机器获取到了租约信息:" + name); } else { LOG.info("LeaseServiceImpl 原子更新租约失败,租约被其他机器获取:" + name); } return success; } } else { // 判断是否是自己获取了租约,如果是自己获取了租约则更新时间(内存和数据库), // 这里是为了解决机器重启的情况,机器重启,内存中没有租约信息,但是实际上该用户是有租约权限的 // fix.2020.08.13,租约的ip与本机ip相等,且满足一致性hash策略,才会被本机执行 String leaseUserIp = validateLeaseInfo.getLeaseUserIp(); if (leaseUserIp.equals(getSelfUser())) { // 如果当期用户有租约信息,则更新数据库 validateLeaseInfo.setLeaseEndDate(time); boolean hasUpdate = updateLeaseInfo(validateLeaseInfo); if (hasUpdate) { LOG.info( "LeaseServiceImpl机器重启情况,当前用户有租约信息,并且更新数据库成功,租约信息为 name :" + validateLeaseInfo.getLeaseName() + " ip : " + validateLeaseInfo.getLeaseUserIp() + " 到期时间 : " + new SimpleDateFormat( "yyyy-MM-dd HH:mm:ss").format(validateLeaseInfo.getLeaseEndDate())); return true; } else { LOG.info("LeaseServiceImpl 机器重启情况,当前用户有租约信息,并且更新数据库失败,表示失去租约:" + name); return false; } } // LOG.info("LeaseServiceImpl 租约被其他机器获取,租约信息为 name :" + validateLeaseInfo.getLeaseName() + " ip : " // + validateLeaseInfo.getLeaseUserIp() + " 到期时间 : " // + new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(validateLeaseInfo.getLeaseEndDate())); return false; } } protected LeaseInfo queryValidateLease(String name) { //String sql = "SELECT * FROM lease_info WHERE lease_name ='" + name + "' and status=1 and lease_end_time>now()"; //// LOG.info("LeaseServiceImpl query validate lease sql:" + sql); //return queryLease(name, sql); return leaseStorage.queryValidateLease(name); }

tryGetLease先通过queryValidateLease查询租约信息,若没有租约则插入,若过期则根据版本号更新,若已有租约则判断是否是自己获取了租约,是则更新租约信息

LeaseServiceImpl public class LeaseServiceImpl extends BasedLesaseImpl { private static final Log LOG = LogFactory.getLog(LeaseServiceImpl.class); private transient ConcurrentHashMap<String, HoldLockTask> holdLockTasks = new ConcurrentHashMap(); protected ConcurrentHashMap<String, HoldLockFunture> seizeLockingFuntures = new ConcurrentHashMap<>(); //如果是抢占锁状态中,则不允许申请锁 public LeaseServiceImpl() { super(); } /** * 尝试获取锁,可以等待waitTime,如果到点未返回,则直接返回。如果是-1,则一直等待 * * @param name 业务名称 * @param lockerName 锁名称 * @param waitTime 等待时间,是微秒单位 * @return */ @Override public boolean tryLocker(String name, String lockerName, long waitTime) { return tryLocker(name, lockerName, waitTime, ILeaseService.DEFALUT_LOCK_TIME); } @Override public boolean tryLocker(String name, String lockerName, long waitTime, int lockTimeSecond) { long now = System.currentTimeMillis(); boolean success = lock(name, lockerName, lockTimeSecond); while (!success) { if (waitTime > -1 && (System.currentTimeMillis() - now > waitTime)) { break; } success = lock(name, lockerName, lockTimeSecond); if (success) { return success; } try { Thread.sleep(100); } catch (InterruptedException e) { LOG.error("LeaseServiceImpl try locker error", e); } } return success; } @Override public boolean lock(String name, String lockerName) { return lock(name, lockerName, ILeaseService.DEFALUT_LOCK_TIME); } @Override public boolean lock(String name, String lockerName, int leaseSecond) { lockerName = createLockName(name, lockerName); Future future = seizeLockingFuntures.get(lockerName); if (future != null && ((HoldLockFunture)future).isDone == false) { return false; } Date nextLeaseDate = DateUtil.addSecond(new Date(), leaseSecond);// 默认锁定5分钟,用完需要立刻释放.如果时间不同步,可能导致锁失败 return tryGetLease(lockerName, nextLeaseDate); } @Override public boolean unlock(String name, String lockerName) { // LOG.info("LeaseServiceImpl unlock,name:" + name); lockerName = createLockName(name, lockerName); LeaseInfo validateLeaseInfo = queryValidateLease(lockerName); if (validateLeaseInfo == null) { LOG.warn("LeaseServiceImpl unlock,validateLeaseInfo is null,lockerName:" + lockerName); } if (validateLeaseInfo != null && validateLeaseInfo.getLeaseUserIp().equals(getSelfUser())) { validateLeaseInfo.setStatus(0); updateDBLeaseInfo(validateLeaseInfo); } HoldLockTask holdLockTask = holdLockTasks.remove(lockerName); if (holdLockTask != null) { holdLockTask.close(); } leaseName2Date.remove(lockerName); return false; } /** * 如果有锁,则一直持有,如果不能获取,则结束。和租约不同,租约是没有也会尝试重试,一备对方挂机,自己可以接手工作 * * @param name * @param secondeName * @param lockTimeSecond 获取锁的时间 * @return */ @Override public boolean holdLock(String name, String secondeName, int lockTimeSecond) { if (hasHoldLock(name, secondeName)) { return true; } synchronized (this) { if (hasHoldLock(name, secondeName)) { return true; } String lockerName = createLockName(name, secondeName); Date nextLeaseDate = DateUtil.addSecond(new Date(), lockTimeSecond); boolean success = tryGetLease(lockerName, nextLeaseDate);// 申请锁,锁的时间是leaseTerm if (!success) { return false; } leaseName2Date.put(lockerName, nextLeaseDate); if (!holdLockTasks.containsKey(lockerName)) { HoldLockTask holdLockTask = new HoldLockTask(lockTimeSecond, lockerName, this); holdLockTask.start(); holdLockTasks.putIfAbsent(lockerName, holdLockTask); } } return true; } /** * 是否持有锁,不访问数据库,直接看本地 * * @param name * @param secondeName * @return */ @Override public boolean hasHoldLock(String name, String secondeName) { String lockerName = createLockName(name, secondeName); return hasLease(lockerName); } @Override public List<LeaseInfo> queryLockedInstanceByNamePrefix(String name, String lockerNamePrefix) { String leaseNamePrefix = MapKeyUtil.createKey(name, lockerNamePrefix); return queryValidateLeaseByNamePrefix(leaseNamePrefix); } //...... }

LeaseServiceImpl继承了BasedLesaseImpl,tryLocker方法会根据等待时间循环执行lock,lock方法则执行tryGetLease,unlock方法则更新租约信息,同时移除内存记录;holdLock则通过hasHoldLock判断是否持有锁,若有则返回,没有则执行tryGetLease

ILeaseStorage public interface ILeaseStorage { /** * 更新lease info,需要是原子操作,存储保障多线程操作的原子性 * * @param leaseInfo 租约表数据 * @return */ boolean updateLeaseInfo(LeaseInfo leaseInfo); /** * 统计这个租约名称下,LeaseInfo对象个数 * * @param leaseName 租约名称,无特殊要求,相同名称会竞争租约 * @return */ Integer countLeaseInfo(String leaseName); /** * 查询无效的的租约 * * @param leaseName 租约名称,无特殊要求,相同名称会竞争租约 * @return */ LeaseInfo queryInValidateLease(String leaseName); /** * 查询有效的的租约 * * @param leaseName 租约名称,无特殊要求,相同名称会竞争租约 * @return */ LeaseInfo queryValidateLease(String leaseName); /** * 按前缀查询有效的租约信息 * * @param namePrefix * @return */ List<LeaseInfo> queryValidateLeaseByNamePrefix(String namePrefix); /** * 增加租约 * * @param leaseInfo 租约名称,无特殊要求,相同名称会竞争租约 */ void addLeaseInfo(LeaseInfo leaseInfo); }

ILeaseStorage接口定义了updateLeaseInfo、countLeaseInfo、queryInValidateLease、queryValidateLease、queryValidateLeaseByNamePrefix、addLeaseInfo方法

DBLeaseStorage public class DBLeaseStorage implements ILeaseStorage { private static final Log LOG = LogFactory.getLog(DBLeaseStorage.class); protected JDBCDriver jdbcDataSource; private String url; protected String userName; protected String password; protected String jdbc; public DBLeaseStorage(String jdbc, String url, String userName, String password) { this.jdbc = jdbc; this.url = url; this.userName = userName; this.password = password; jdbcDataSource = DriverBuilder.createDriver(jdbc, url, userName, password); } @Override public boolean updateLeaseInfo(LeaseInfo leaseInfo) { String sql = "UPDATE lease_info SET version=version+1,status=#{status},gmt_modified=now()"; String whereSQL = " WHERE id=#{id} and version=#{version}"; if (StringUtil.isNotEmpty(leaseInfo.getLeaseName())) { sql += ",lease_name=#{leaseName}"; } if (StringUtil.isNotEmpty(leaseInfo.getLeaseUserIp())) { sql += ",lease_user_ip=#{leaseUserIp}"; } if (leaseInfo.getLeaseEndDate() != null) { sql += ",lease_end_time=#{leaseEndDate}"; } sql += whereSQL; sql = SQLUtil.parseIbatisSQL(leaseInfo, sql); try { int count = getOrCreateJDBCDataSource().update(sql); boolean success = count > 0; if (success) { synchronized (this) { leaseInfo.setVersion(leaseInfo.getVersion() + 1); } } else { System.out.println(count); } return success; } catch (Exception e) { LOG.error("LeaseServiceImpl updateLeaseInfo excuteUpdate error", e); throw new RuntimeException("execute sql error " + sql, e); } } @Override public Integer countLeaseInfo(String leaseName) { String sql = "SELECT count(*) as c FROM lease_info WHERE lease_name = '" + leaseName + "' and status = 1"; try { List<Map<String, Object>> rows = getOrCreateJDBCDataSource().queryForList(sql); if (rows == null || rows.size() == 0) { return null; } Long value = (Long) rows.get(0).get("c"); return value.intValue(); } catch (Exception e) { throw new RuntimeException("execute sql error " + sql, e); } } @Override public LeaseInfo queryInValidateLease(String leaseName) { String sql = "SELECT * FROM lease_info WHERE lease_name ='" + leaseName + "' and status=1 and lease_end_time<'" + DateUtil.getCurrentTimeString() + "'"; LOG.info("LeaseServiceImpl queryInValidateLease builder:" + sql); return queryLease(leaseName, sql); } @Override public LeaseInfo queryValidateLease(String leaseName) { String sql = "SELECT * FROM lease_info WHERE lease_name ='" + leaseName + "' and status=1 and lease_end_time>now()"; return queryLease(leaseName, sql); } @Override public List<LeaseInfo> queryValidateLeaseByNamePrefix(String namePrefix) { String sql = "SELECT * FROM lease_info WHERE lease_name like '" + namePrefix + "%' and status=1 and lease_end_time>now()"; try { List<LeaseInfo> leaseInfos = new ArrayList<>(); List<Map<String, Object>> rows = getOrCreateJDBCDataSource().queryForList(sql); if (rows == null || rows.size() == 0) { return null; } for (Map<String, Object> row : rows) { LeaseInfo leaseInfo = convert(row); leaseInfos.add(leaseInfo); } return leaseInfos; } catch (Exception e) { throw new RuntimeException("execute sql error " + sql, e); } } @Override public void addLeaseInfo(LeaseInfo leaseInfo) { String sql = " REPLACE INTO lease_info(lease_name,lease_user_ip,lease_end_time,status,version,gmt_create,gmt_modified)" + " VALUES (#{leaseName},#{leaseUserIp},#{leaseEndDate},#{status},#{version},now(),now())"; sql = SQLUtil.parseIbatisSQL(leaseInfo, sql); try { getOrCreateJDBCDataSource().execute(sql); } catch (Exception e) { LOG.error("LeaseServiceImpl execute sql error,sql:" + sql, e); throw new RuntimeException("execute sql error " + sql, e); } } protected JDBCDriver getOrCreateJDBCDataSource() { if (this.jdbcDataSource == null || !this.jdbcDataSource.isValidate()) { synchronized (this) { if (this.jdbcDataSource == null || !this.jdbcDataSource.isValidate()) { this.jdbcDataSource = DriverBuilder.createDriver(this.jdbc, this.url, this.userName, this.password); } } } return jdbcDataSource; } protected LeaseInfo queryLease(String name, String sql) { try { List<Map<String, Object>> rows = getOrCreateJDBCDataSource().queryForList(sql); if (rows == null || rows.size() == 0) { return null; } return convert(rows.get(0)); } catch (Exception e) { throw new RuntimeException("execute sql error " + sql, e); } } protected LeaseInfo convert(Map<String, Object> map) { LeaseInfo leaseInfo = new LeaseInfo(); leaseInfo.setId(getMapLongValue("id", map)); leaseInfo.setCreateTime(getMapDateValue("gmt_create", map)); leaseInfo.setLeaseEndDate(getMapDateValue("lease_end_time", map)); leaseInfo.setLeaseName(getMapValue("lease_name", map, String.class)); leaseInfo.setLeaseUserIp(getMapValue("lease_user_ip", map, String.class)); Integer status = getMapValue("status", map, Integer.class); if (status != null) { leaseInfo.setStatus(status); } leaseInfo.setUpdateTime(getMapDateValue("gmt_modified", map)); Long version = getMapLongValue("version", map); if (version != null) { leaseInfo.setVersion(version); } return leaseInfo; } @SuppressWarnings("unchecked") private <T> T getMapValue(String fieldName, Map<String, Object> map, Class<T> integerClass) { Object value = map.get(fieldName); if (value == null) { return null; } return (T) value; } private Long getMapLongValue(String fieldName, Map<String, Object> map) { Object value = map.get(fieldName); if (value == null) { return null; } if (value instanceof Long) { return (Long) value; } if (value instanceof BigInteger) { return ((BigInteger) value).longValue(); } return null; } private Date getMapDateValue(String fieldName, Map<String, Object> map) { Object value = map.get(fieldName); if (value == null) { return null; } if (value instanceof Date) { return (Date) value; } if (value instanceof String) { return DateUtil.parseTime(((String) value)); } return null; } }

DBLeaseStorage实现了ILeaseStorage接口,使用jdbc实现了其方法

小结

rocketmq-streams的LeaseService基于db实现了租约和锁,可用于主备场景切换。

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