/**
* Notify the ChronologyProtector that the LBFactory is done calling shutdownLB() for now.
* May commit chronology data to persistent storage.
*
* @return array Empty on success; returns the (db name => position) map on failure
*/
public function shutdown()
{
if (!$this->enabled || !count($this->shutdownPositions)) {
return true;
// nothing to save
}
wfDebugLog('replication', __METHOD__ . ": saving master pos for " . implode(', ', array_keys($this->shutdownPositions)) . "\n");
$shutdownPositions = $this->shutdownPositions;
$ok = $this->store->merge($this->key, function ($store, $key, $curValue) use($shutdownPositions) {
/** @var $curPositions DBMasterPos[] */
if ($curValue === false) {
$curPositions = $shutdownPositions;
} else {
$curPositions = $curValue['positions'];
// Use the newest positions for each DB master
foreach ($shutdownPositions as $db => $pos) {
if (!isset($curPositions[$db]) || $pos->asOfTime() > $curPositions[$db]->asOfTime()) {
$curPositions[$db] = $pos;
}
}
}
return array('positions' => $curPositions);
}, BagOStuff::TTL_MINUTE, 10, BagOStuff::WRITE_SYNC);
if (!$ok) {
// Raced out too many times or stash is down
wfDebugLog('replication', __METHOD__ . ": failed to save master pos for " . implode(', ', array_keys($this->shutdownPositions)) . "\n");
return $this->shutdownPositions;
}
return array();
}
/**
* Set the cached stat info for a file path.
* Negatives (404s) are not cached. By not caching negatives, we can skip cache
* salting for the case when a file is created at a path were there was none before.
*
* @param string $path Storage path
* @param array $val Stat information to cache
*/
protected final function setFileCache($path, array $val)
{
$path = FileBackend::normalizeStoragePath($path);
if ($path === null) {
return;
// invalid storage path
}
$age = time() - wfTimestamp(TS_UNIX, $val['mtime']);
$ttl = min(7 * 86400, max(300, floor(0.1 * $age)));
$key = $this->fileCacheKey($path);
// Set the cache unless it is currently salted with the value "PURGED".
// Using add() handles this except it also is a no-op in that case where
// the current value is not "latest" but $val is, so use CAS in that case.
if (!$this->memCache->add($key, $val, $ttl) && !empty($val['latest'])) {
$this->memCache->merge($key, function (BagOStuff $cache, $key, $cValue) use($val) {
return is_array($cValue) && empty($cValue['latest']) ? $val : false;
// do nothing (cache is salted or some error happened)
}, $ttl, 1);
}
}
/**
* @covers BagOStuff::merge
* @covers BagOStuff::mergeViaLock
*/
public function testMerge()
{
$key = wfMemcKey('test');
$usleep = 0;
/**
* Callback method: append "merged" to whatever is in cache.
*
* @param BagOStuff $cache
* @param string $key
* @param int $existingValue
* @use int $usleep
* @return int
*/
$callback = function (BagOStuff $cache, $key, $existingValue) use(&$usleep) {
// let's pretend this is an expensive callback to test concurrent merge attempts
usleep($usleep);
if ($existingValue === false) {
return 'merged';
}
return $existingValue . 'merged';
};
// merge on non-existing value
$merged = $this->cache->merge($key, $callback, 0);
$this->assertTrue($merged);
$this->assertEquals($this->cache->get($key), 'merged');
// merge on existing value
$merged = $this->cache->merge($key, $callback, 0);
$this->assertTrue($merged);
$this->assertEquals($this->cache->get($key), 'mergedmerged');
/*
* Test concurrent merges by forking this process, if:
* - not manually called with --use-bagostuff
* - pcntl_fork is supported by the system
* - cache type will correctly support calls over forks
*/
$fork = (bool) $this->getCliArg('use-bagostuff');
$fork &= function_exists('pcntl_fork');
$fork &= !$this->cache instanceof HashBagOStuff;
$fork &= !$this->cache instanceof EmptyBagOStuff;
$fork &= !$this->cache instanceof MultiWriteBagOStuff;
if ($fork) {
// callback should take awhile now so that we can test concurrent merge attempts
$pid = pcntl_fork();
if ($pid == -1) {
// can't fork, ignore this test...
} elseif ($pid) {
// wait a little, making sure that the child process is calling merge
usleep(3000);
// attempt a merge - this should fail
$merged = $this->cache->merge($key, $callback, 0, 1);
// merge has failed because child process was merging (and we only attempted once)
$this->assertFalse($merged);
// make sure the child's merge is completed and verify
usleep(3000);
$this->assertEquals($this->cache->get($key), 'mergedmergedmerged');
} else {
$this->cache->merge($key, $callback, 0, 1);
// Note: I'm not even going to check if the merge worked, I'll
// compare values in the parent process to test if this merge worked.
// I'm just going to exit this child process, since I don't want the
// child to output any test results (would be rather confusing to
// have test output twice)
exit;
}
}
}
public function merge($key, $callback, $exptime = 0, $attempts = 10)
{
return $this->writeStore->merge($key, $callback, $exptime, $attempts);
}
