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Merge "objectcache: fix race conditions in RedisBagOStuff::incr()"

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jenkins-bot 2019-07-13 23:57:32 +00:00 committed by Gerrit Code Review
commit 76f5c309ad
1 changed files with 59 additions and 37 deletions
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96
includes/libs/objectcache/RedisBagOStuff.php
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@ -116,7 +116,6 @@ class RedisBagOStuff extends BagOStuff {
if ( $ttl ) {
$result = $conn->setex( $key, $ttl, $this->serialize( $value ) );
} else {
// No expiry, that is very different from zero expiry in Redis
$result = $conn->set( $key, $this->serialize( $value ) );
}
} catch ( RedisException $e ) {
@ -215,11 +214,7 @@ class RedisBagOStuff extends BagOStuff {
$this->debug( "setMulti request to $server failed" );
continue;
}
foreach ( $batchResult as $value ) {
if ( $value === false ) {
$result = false;
}
}
$result = $result && !in_array( false, $batchResult, true );
} catch ( RedisException $e ) {
$this->handleException( $conn, $e );
$result = false;
@ -254,11 +249,7 @@ class RedisBagOStuff extends BagOStuff {
$this->debug( "deleteMulti request to $server failed" );
continue;
}
foreach ( $batchResult as $value ) {
if ( $value === false ) {
$result = false;
}
}
$result = $result && !in_array( false, $batchResult, true );
} catch ( RedisException $e ) {
$this->handleException( $conn, $e );
$result = false;
@ -273,55 +264,86 @@ class RedisBagOStuff extends BagOStuff {
if ( !$conn ) {
return false;
}
$expiry = $this->convertToRelative( $expiry );
$ttl = $this->convertToRelative( $expiry );
try {
if ( $expiry ) {
$result = $conn->set(
$key,
$this->serialize( $value ),
[ 'nx', 'ex' => $expiry ]
);
} else {
$result = $conn->setnx( $key, $this->serialize( $value ) );
}
$result = $conn->set(
$key,
$this->serialize( $value ),
$ttl ? [ 'nx', 'ex' => $ttl ] : [ 'nx' ]
);
} catch ( RedisException $e ) {
$result = false;
$this->handleException( $conn, $e );
}
$this->logRequest( 'add', $key, $server, $result );
return $result;
}
/**
* Non-atomic implementation of incr().
*
* Probably all callers actually want incr() to atomically initialise
* values to zero if they don't exist, as provided by the Redis INCR
* command. But we are constrained by the memcached-like interface to
* return null in that case. Once the key exists, further increments are
* atomic.
* @param string $key Key to increase
* @param int $value Value to add to $key (Default 1)
* @return int|bool New value or false on failure
*/
public function incr( $key, $value = 1 ) {
list( $server, $conn ) = $this->getConnection( $key );
if ( !$conn ) {
return false;
}
try {
if ( !$conn->exists( $key ) ) {
return false;
$conn->watch( $key );
if ( $conn->exists( $key ) ) {
$conn->multi( Redis::MULTI );
$conn->incrBy( $key, $value );
$batchResult = $conn->exec();
if ( $batchResult === false ) {
$result = false;
} else {
$result = end( $batchResult );
}
} else {
$result = false;
$conn->unwatch();
}
} catch ( RedisException $e ) {
try {
$conn->unwatch(); // sanity
} catch ( RedisException $ex ) {
// already errored
}
$result = false;
$this->handleException( $conn, $e );
}
$this->logRequest( 'incr', $key, $server, $result );
return $result;
}
public function incrWithInit( $key, $exptime, $value = 1, $init = 1 ) {
list( $server, $conn ) = $this->getConnection( $key );
if ( !$conn ) {
return false;
}
$ttl = $this->convertToRelative( $exptime );
$preIncrInit = $init - $value;
try {
$conn->multi( Redis::MULTI );
$conn->set( $key, $preIncrInit, $ttl ? [ 'nx', 'ex' => $ttl ] : [ 'nx' ] );
$conn->incrBy( $key, $value );
$batchResult = $conn->exec();
if ( $batchResult === false ) {
$result = false;
$this->debug( "incrWithInit request to $server failed" );
} else {
$result = end( $batchResult );
}
// @FIXME: on races, the key may have a 0 TTL
$result = $conn->incrBy( $key, $value );
} catch ( RedisException $e ) {
$result = false;
$this->handleException( $conn, $e );
}
$this->logRequest( 'incr', $key, $server, $result );
return $result;
}