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83 lines
2.6 KiB
Go
83 lines
2.6 KiB
Go
package pub_balancer
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import (
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cmap "github.com/orcaman/concurrent-map/v2"
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"github.com/seaweedfs/seaweedfs/weed/glog"
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"github.com/seaweedfs/seaweedfs/weed/pb/mq_pb"
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"math/rand"
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"time"
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)
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func AllocateTopicPartitions(brokers cmap.ConcurrentMap[string, *BrokerStats], partitionCount int32) (assignments []*mq_pb.BrokerPartitionAssignment) {
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// divide the ring into partitions
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now := time.Now().UnixNano()
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rangeSize := MaxPartitionCount / partitionCount
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for i := int32(0); i < partitionCount; i++ {
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assignment := &mq_pb.BrokerPartitionAssignment{
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Partition: &mq_pb.Partition{
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RingSize: MaxPartitionCount,
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RangeStart: int32(i * rangeSize),
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RangeStop: int32((i + 1) * rangeSize),
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UnixTimeNs: now,
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},
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}
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if i == partitionCount-1 {
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assignment.Partition.RangeStop = MaxPartitionCount
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}
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assignments = append(assignments, assignment)
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}
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// pick the brokers
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pickedBrokers := pickBrokers(brokers, partitionCount)
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// assign the partitions to brokers
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for i, assignment := range assignments {
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assignment.LeaderBroker = pickedBrokers[i]
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}
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glog.V(0).Infof("allocate topic partitions %d: %v", len(assignments), assignments)
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return
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}
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// for now: randomly pick brokers
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// TODO pick brokers based on the broker stats
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func pickBrokers(brokers cmap.ConcurrentMap[string, *BrokerStats], count int32) []string {
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candidates := make([]string, 0, brokers.Count())
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for brokerStatsItem := range brokers.IterBuffered() {
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candidates = append(candidates, brokerStatsItem.Key)
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}
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pickedBrokers := make([]string, 0, count)
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for i := int32(0); i < count; i++ {
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p := rand.Int() % len(candidates)
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if p < 0 {
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p = -p
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}
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pickedBrokers = append(pickedBrokers, candidates[p])
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}
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return pickedBrokers
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}
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func EnsureAssignmentsToActiveBrokers(activeBrokers cmap.ConcurrentMap[string,*BrokerStats], assignments []*mq_pb.BrokerPartitionAssignment) (addedAssignments, updatedAssignments []*mq_pb.BrokerPartitionAssignment) {
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for _, assignment := range assignments {
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if assignment.LeaderBroker == "" {
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addedAssignments = append(addedAssignments, assignment)
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continue
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}
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if _, found := activeBrokers.Get(assignment.LeaderBroker); !found {
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updatedAssignments = append(updatedAssignments, assignment)
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continue
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}
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}
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// pick the brokers with the least number of partitions
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pickedBrokers := pickBrokers(activeBrokers, int32(len(addedAssignments)))
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for i, assignment := range addedAssignments {
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assignment.LeaderBroker = pickedBrokers[i]
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}
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pickedBrokers = pickBrokers(activeBrokers, int32(len(updatedAssignments)))
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for i, assignment := range updatedAssignments {
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assignment.LeaderBroker = pickedBrokers[i]
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}
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return
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}
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