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本文次要钻研一下 jedis 的 return 行为
spring-data-redis
RedisTemplate
org/springframework/data/redis/core/RedisTemplate.java
@Nullable
public <T> T execute(RedisCallback<T> action, boolean exposeConnection, boolean pipeline) {Assert.isTrue(initialized, "template not initialized; call afterPropertiesSet() before using it");
Assert.notNull(action, "Callback object must not be null");
RedisConnectionFactory factory = getRequiredConnectionFactory();
RedisConnection conn = RedisConnectionUtils.getConnection(factory, enableTransactionSupport);
try {boolean existingConnection = TransactionSynchronizationManager.hasResource(factory);
RedisConnection connToUse = preProcessConnection(conn, existingConnection);
boolean pipelineStatus = connToUse.isPipelined();
if (pipeline && !pipelineStatus) {connToUse.openPipeline();
}
RedisConnection connToExpose = (exposeConnection ? connToUse : createRedisConnectionProxy(connToUse));
T result = action.doInRedis(connToExpose);
// close pipeline
if (pipeline && !pipelineStatus) {connToUse.closePipeline();
}
return postProcessResult(result, connToUse, existingConnection);
} finally {RedisConnectionUtils.releaseConnection(conn, factory, enableTransactionSupport);
}
}RedisTemplate 的 execute 办法先通过 RedisConnectionUtils.getConnection 获取连贯，最初通过 RedisConnectionUtils.releaseConnection 来偿还连贯
RedisConnectionUtils
org/springframework/data/redis/core/RedisConnectionUtils.java
public static void releaseConnection(@Nullable RedisConnection conn, RedisConnectionFactory factory,
boolean transactionSupport) {releaseConnection(conn, factory);
}
public static void releaseConnection(@Nullable RedisConnection conn, RedisConnectionFactory factory) {if (conn == null) {return;}
RedisConnectionHolder conHolder = (RedisConnectionHolder) TransactionSynchronizationManager.getResource(factory);
if (conHolder != null) {if (conHolder.isTransactionActive()) {if (connectionEquals(conHolder, conn)) {if (log.isDebugEnabled()) {log.debug("RedisConnection will be closed when transaction finished.");
}
// It's the transactional Connection: Don't close it.
conHolder.released();}
return;
}
// release transactional/read-only and non-transactional/non-bound connections.
// transactional connections for read-only transactions get no synchronizer registered
unbindConnection(factory);
return;
}
doCloseConnection(conn);
}
private static void doCloseConnection(@Nullable RedisConnection connection) {if (connection == null) {return;}
if (log.isDebugEnabled()) {log.debug("Closing Redis Connection.");
}
try {connection.close();
} catch (DataAccessException ex) {log.debug("Could not close Redis Connection", ex);
} catch (Throwable ex) {log.debug("Unexpected exception on closing Redis Connection", ex);
}
}releaseConnection 办法次要是解决了事务相干的操作，最初执行 doCloseConnection，它最初执行的是 connection.close()
connection.close()
org/springframework/data/redis/connection/jedis/JedisConnection.java
@Override
public void close() throws DataAccessException {super.close();
JedisSubscription subscription = this.subscription;
try {if (subscription != null) {subscription.close();
}
} catch (Exception ex) {LOGGER.debug("Cannot terminate subscription", ex);
} finally {this.subscription = null;}
// return the connection to the pool
if (pool != null) {jedis.close();
return;
}
// else close the connection normally (doing the try/catch dance)
try {jedis.quit();
} catch (Exception ex) {LOGGER.debug("Failed to QUIT during close", ex);
}
try {jedis.disconnect();
} catch (Exception ex) {LOGGER.debug("Failed to disconnect during close", ex);
}
}connection 的 close 办法针对应用连接池的会执行 jedis.close，否则执行 jedis.quit
jedis.close()
redis/clients/jedis/Jedis.java
@Override
public void close() {if (dataSource != null) {
JedisPoolAbstract pool = this.dataSource;
this.dataSource = null;
if (isBroken()) {pool.returnBrokenResource(this);
} else {pool.returnResource(this);
}
} else {super.close();
}
}jedis 的 close 办法会先判断 isBroken(
取的 redis.clients.jedis.Connection.broken 属性)，如果是则执行 returnBrokenResource，否则执行 returnResource
pool
redis/clients/jedis/util/Pool.java
public void returnBrokenResource(final T resource) {if (resource != null) {returnBrokenResourceObject(resource);
}
}
public void returnResource(final T resource) {if (resource != null) {returnResourceObject(resource);
}
}
protected void returnBrokenResourceObject(final T resource) {
try {internalPool.invalidateObject(resource);
} catch (Exception e) {throw new JedisException("Could not return the broken resource to the pool", e);
}
}
protected void returnResourceObject(final T resource) {
try {internalPool.returnObject(resource);
} catch (RuntimeException e) {throw new JedisException("Could not return the resource to the pool", e);
}
}returnBrokenResource 执行的是 internalPool.invalidateObject(resource)，而 returnResourceObject 执行的是 internalPool.returnObject(resource)
invalidateObject
org/apache/commons/pool2/impl/GenericObjectPool.java
public void invalidateObject(final T obj, final DestroyMode destroyMode) throws Exception {final PooledObject<T> p = getPooledObject(obj);
if (p == null) {if (isAbandonedConfig()) {return;}
throw new IllegalStateException("Invalidated object not currently part of this pool");
}
synchronized (p) {if (p.getState() != PooledObjectState.INVALID) {destroy(p, destroyMode);
}
}
ensureIdle(1, false);
}
private void destroy(final PooledObject<T> toDestroy, final DestroyMode destroyMode) throws Exception {toDestroy.invalidate();
idleObjects.remove(toDestroy);
allObjects.remove(new IdentityWrapper<>(toDestroy.getObject()));
try {factory.destroyObject(toDestroy, destroyMode);
} finally {destroyedCount.incrementAndGet();
createCount.decrementAndGet();}
}invalidateObject 办法执行的是 destroy 办法，该办法会回调 factory.destroyObject
destroyObject
redis/clients/jedis/JedisFactory.java
public void destroyObject(PooledObject<Jedis> pooledJedis) throws Exception {final BinaryJedis jedis = pooledJedis.getObject();
if (jedis.isConnected()) {
try {
// need a proper test, probably with mock
if (!jedis.isBroken()) {jedis.quit();
}
} catch (RuntimeException e) {logger.warn("Error while QUIT", e);
}
try {jedis.close();
} catch (RuntimeException e) {logger.warn("Error while close", e);
}
}
}destroyObject 办法则执行 jedis.close()敞开 client 连贯
returnObject
org/apache/commons/pool2/impl/GenericObjectPool.java
public void returnObject(final T obj) {final PooledObject<T> p = getPooledObject(obj);
if (p == null) {if (!isAbandonedConfig()) {
throw new IllegalStateException("Returned object not currently part of this pool");
}
return; // Object was abandoned and removed
}
markReturningState(p);
final Duration activeTime = p.getActiveDuration();
if (getTestOnReturn() && !factory.validateObject(p)) {
try {destroy(p, DestroyMode.NORMAL);
} catch (final Exception e) {swallowException(e);
}
try {ensureIdle(1, false);
} catch (final Exception e) {swallowException(e);
}
updateStatsReturn(activeTime);
return;
}
try {factory.passivateObject(p);
} catch (final Exception e1) {swallowException(e1);
try {destroy(p, DestroyMode.NORMAL);
} catch (final Exception e) {swallowException(e);
}
try {ensureIdle(1, false);
} catch (final Exception e) {swallowException(e);
}
updateStatsReturn(activeTime);
return;
}
if (!p.deallocate()) {
throw new IllegalStateException("Object has already been returned to this pool or is invalid");
}
final int maxIdleSave = getMaxIdle();
if (isClosed() || maxIdleSave > -1 && maxIdleSave <= idleObjects.size()) {
try {destroy(p, DestroyMode.NORMAL);
} catch (final Exception e) {swallowException(e);
}
try {ensureIdle(1, false);
} catch (final Exception e) {swallowException(e);
}
} else {if (getLifo()) {idleObjects.addFirst(p);
} else {idleObjects.addLast(p);
}
if (isClosed()) {
// Pool closed while object was being added to idle objects.
// Make sure the returned object is destroyed rather than left
// in the idle object pool (which would effectively be a leak)
clear();}
}
updateStatsReturn(activeTime);
}returnObject 针对 testOnReturn 的会执行 validateObject 办法，之后执行 factory.passivateObject(p)，最初依据 maxIdle 的参数来判断，超出的则执行 destroy，否则依据是否 Lifo 放回到连接池 (
idleObjects) 中
小结
spring-data-redis 的 return 次要是执行 connection 的 close 办法，对应到 jedis 就是 jedis.close()，它会先判断 isBroken(取的 redis.clients.jedis.Connection.broken 属性)，如果是则执行 returnBrokenResource，否则执行 returnResource。
- returnBrokenResource 执行的是 internalPool.invalidateObject(resource)，invalidateObject 办法执行的是 destroy 办法，该办法会回调 factory.destroyObject 办法，即执行 jedis.close()敞开 client 连贯
- returnObject 针对 testOnReturn 的会执行 validateObject 办法，之后执行 factory.passivateObject(p)，最初依据 maxIdle 的参数来判断，超出的则执行 destroy，否则依据是否 Lifo 放回到连接池 (
idleObjects) 中 - 也就说假如获取连贯之后，执行的时候 redis 挂了，redis.clients.jedis.Connection 会标记 broken 为 true，同时抛出 JedisConnectionException；而 RedisTemplate 是在 finally 中进行 releaseConnection，因此偿还的时候会触发 returnBrokenResource 从而敞开坏掉的连贯，间接实现
testOnReturn的成果 - 如果在获取连贯的时候，redis 挂了，然而连接池依然有连贯，若没有 testOnBorrow 则返回而后应用，然而应用的时候会报错，即 redis.clients.jedis.Connection 会标记 broken 为 true，同时抛出 JedisConnectionException，偿还的时候间接销毁；若有 testOnBorrow 则 validate 的时候能验证进去连贯有问题，则会执行 destory 而后持续循环获取连接池的连贯，直到连接池连贯没有了；若获取连贯的时候连接池没有闲暇连贯了，则走 create 的逻辑，这个时候 create 间接抛出 redis.clients.jedis.exceptions.JedisConnectionException: Failed to create socket.
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