-
- function getBucketMemcache()
- {
- static $m;
-
- if (!CONST_ConnectionBucket_MemcacheServerAddress) return null;
- if (!isset($m))
- {
- $m = new Memcached();
- $m->addServer(CONST_ConnectionBucket_MemcacheServerAddress, CONST_ConnectionBucket_MemcacheServerPort);
- }
- return $m;
- }
-
- function doBucket($asKey, $iRequestCost, $iLeakPerSecond, $iThreshold)
- {
- $m = getBucketMemcache();
- if (!$m) return 0;
-
- $iMaxVal = 0;
- $t = time();
-
- foreach($asKey as $sKey)
- {
- $aCurrentBlock = $m->get($sKey);
- if (!$aCurrentBlock)
- {
- $aCurrentBlock = array($iRequestCost, $t);
- }
- else
- {
- // add RequestCost
- // remove leak * the time since the last request
- $aCurrentBlock[0] += $iRequestCost - ($t - $aCurrentBlock[1])*$iLeakPerSecond;
- $aCurrentBlock[1] = $t;
- }
-
- if ($aCurrentBlock[0] <= 0)
- {
- $m->delete($sKey);
- }
- else
- {
- // If we have hit the threshold stop and record this to the block list
- if ($aCurrentBlock[0] >= $iThreshold)
- {
- $aCurrentBlock[0] = $iThreshold;
-
- // Make up to 10 attempts to record this to memcache (with locking to prevent conflicts)
- $i = 10;
- for($i = 0; $i < 10; $i++)
- {
- $aBlockedList = $m->get('blockedList', null, $hCasToken);
- if (!$aBlockedList)
- {
- $aBlockedList = array();
- $m->add('blockedList', $aBlockedList);
- $aBlockedList = $m->get('blockedList', null, $hCasToken);
- }
- if (!isset($aBlockedList[$sKey]))
- {
- $aBlockedList[$sKey] = array(1, $t);
- }
- else
- {
- $aBlockedList[$sKey][0]++;
- $aBlockedList[$sKey][1] = $t;
- }
- $x = $m->cas($hCasToken, 'blockedList', $aBlockedList);
- if ($x) break;
- }
- }
- // Only keep in memcache until the time it would have expired (to avoid clutering memcache)
- $m->set($sKey, $aCurrentBlock, $t + 1 + $aCurrentBlock[0]/$iLeakPerSecond);
- }
-
- // Bucket result in the largest bucket we find
- $iMaxVal = max($iMaxVal, $aCurrentBlock[0]);
- }
-
- return $iMaxVal;
- }
-
- function byLastBlockTime($a, $b)
- {
- if ($a['lastBlockTimestamp'] == $b['lastBlockTimestamp'])
- {
- return 0;
- }
- return ($a['lastBlockTimestamp'] > $b['lastBlockTimestamp']) ? -1 : 1;
- }
-
- function getBucketBlocks()
- {
- $m = getBucketMemcache();
- if (!$m) return null;
- $t = time();
- $aBlockedList = $m->get('blockedList', null, $hCasToken);
- if (!$aBlockedList) $aBlockedList = array();
- foreach($aBlockedList as $sKey => $aDetails)
- {
- $aCurrentBlock = $m->get($sKey);
- if (!$aCurrentBlock) $aCurrentBlock = array(0, $t);
- $iCurrentBucketSize = max(0, $aCurrentBlock[0] - ($t - $aCurrentBlock[1])*CONST_ConnectionBucket_LeakRate);
- $aBlockedList[$sKey] = array(
- 'totalBlocks' => $aDetails[0],
- 'lastBlockTimestamp' => $aDetails[1],
- 'currentBucketSize' => $iCurrentBucketSize,
- 'lastRequestBlocked' => $aCurrentBlock[0] >= CONST_ConnectionBucket_BlockLimit,
- 'currentlyBlocked' => $iCurrentBucketSize + (CONST_ConnectionBucket_Cost_Reverse) >= CONST_ConnectionBucket_BlockLimit,
- );
- }
- uasort($aBlockedList, 'byLastBlockTime');
- return $aBlockedList;
- }
-
- function clearBucketBlocks()
- {
- $m = getBucketMemcache();
- if (!$m) return false;
- $m->delete('blockedList');
- return true;
- }