/**
* Switch to the given node and map the cluster from its HELLO
*
* @param Node $node
*/
private function switchToNode(Node $node)
{
$nodeId = $node->getId();
// Return early if we're trying to switch to the current node.
if ($this->nodeId === $nodeId) {
// But return early only if the current node is connected to Disque.
// If it is disconnected, we want to overwrite it with the node
// from the method argument, because that one is connected.
if ($this->getCurrentNode()->isConnected()) {
return;
}
// Copy the stats from the now-disconnected node object
$this->copyNodeStats($this->getCurrentNode(), $node);
}
$this->resetNodeCounters();
$this->nodeId = $nodeId;
$this->nodes[$nodeId] = $node;
$this->revealClusterFromHello($node);
}
/**
* Calculate the node priority from its job count, stick to the current node
*
* As the priority is based on the number of jobs, higher is better.
*
* @param Node $node
* @param string $currentNodeId
*
* @return float Node priority
*/
private function calculateNodePriority(Node $node, $currentNodeId)
{
$priority = $node->getJobCount();
if ($node->getId() === $currentNodeId) {
$margin = 1 + $this->marginToSwitch;
$priority = $priority * $margin;
}
// Apply a weight determined by the node priority as assigned by Disque.
// Priority 1 means the node is healthy.
// Priority 10 to 100 means the node is probably failing, or has failed
$disquePriority = $node->getPriority();
// Disque node priority should never be lower than 1, but let's be sure
if ($disquePriority < Node::PRIORITY_OK) {
$disquePriorityWeight = 1;
} elseif (Node::PRIORITY_OK <= $disquePriority && $disquePriority < Node::PRIORITY_POSSIBLE_FAILURE) {
// Node is OK, but Disque may have assigned a lower priority to it
// We use the base-10 logarithm in the formula, so priorities
// 1 to 10 transform into a weight of 1 to 0.5. When Disque starts
// using more priority steps, priority 9 will discount about a half
// of the job count.
$disquePriorityWeight = 1 / (1 + log10($disquePriority));
} else {
// Node is failing, or it has failed
$disquePriorityWeight = 0;
}
$priority = $priority * $disquePriorityWeight;
return (double) $priority;
}
/**
* Switch to the given node and map the cluster from its HELLO
*
* @param Node $node
*/
private function switchToNode(Node $node)
{
$nodeId = $node->getId();
if ($this->nodeId === $nodeId) {
return;
}
$this->resetNodeCounters();
$this->nodeId = $nodeId;
$this->nodes[$nodeId] = $node;
$this->revealClusterFromHello($node);
}
