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92 lines
2.3 KiB
92 lines
2.3 KiB
package coordinator
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import (
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"github.com/seaweedfs/seaweedfs/weed/mq/topic"
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"sync"
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)
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func (cg *ConsumerGroup) SetMinMaxActiveInstances(min, max int32) {
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cg.MinimumActiveInstances = min
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cg.MaximumActiveInstances = max
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}
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func (cg *ConsumerGroup) AddConsumerGroupInstance(clientId string) *ConsumerGroupInstance {
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cgi := &ConsumerGroupInstance{
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ClientId: clientId,
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}
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cg.ConsumerGroupInstances.Set(clientId, cgi)
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return cgi
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}
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func (cg *ConsumerGroup) RemoveConsumerGroupInstance(clientId string) {
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cg.ConsumerGroupInstances.Remove(clientId)
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}
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func (cg *ConsumerGroup) CoordinateIfNeeded() {
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emptyInstanceCount, activeInstanceCount := int32(0), int32(0)
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for cgi := range cg.ConsumerGroupInstances.IterBuffered() {
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if cgi.Val.Partition == nil {
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// this consumer group instance is not assigned a partition
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// need to assign one
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emptyInstanceCount++
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} else {
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activeInstanceCount++
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}
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}
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var delta int32
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if emptyInstanceCount > 0 {
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if cg.MinimumActiveInstances <= 0 {
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// need to assign more partitions
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delta = emptyInstanceCount
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} else if activeInstanceCount < cg.MinimumActiveInstances && activeInstanceCount+emptyInstanceCount >= cg.MinimumActiveInstances {
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// need to assign more partitions
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delta = cg.MinimumActiveInstances - activeInstanceCount
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}
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}
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if cg.MaximumActiveInstances > 0 {
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if activeInstanceCount > cg.MaximumActiveInstances {
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// need to remove some partitions
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delta = cg.MaximumActiveInstances - activeInstanceCount
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}
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}
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if delta == 0 {
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return
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}
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cg.doCoordinate(activeInstanceCount + delta)
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}
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func (cg *ConsumerGroup) doCoordinate(target int32) {
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// stop existing instances from processing
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var wg sync.WaitGroup
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for cgi := range cg.ConsumerGroupInstances.IterBuffered() {
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if cgi.Val.Partition != nil {
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wg.Add(1)
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go func(cgi *ConsumerGroupInstance) {
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defer wg.Done()
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// stop processing
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// flush internal state
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// wait for all messages to be processed
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// close the connection
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}(cgi.Val)
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}
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}
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wg.Wait()
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partitions := topic.SplitPartitions(target)
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// assign partitions to new instances
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i := 0
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for cgi := range cg.ConsumerGroupInstances.IterBuffered() {
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cgi.Val.Partition = partitions[i]
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i++
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wg.Add(1)
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go func(cgi *ConsumerGroupInstance) {
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defer wg.Done()
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// start processing
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// start consuming from the last offset
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}(cgi.Val)
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}
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wg.Wait()
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}
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