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本文主要研究一下tempo的ExclusiveQueues
ExclusiveQueues
tempo/pkg/flushqueues/exclusivequeues.go
type ExclusiveQueues struct {
queues []*util.PriorityQueue
index *atomic.Int32
activeKeys sync.Map
}
ExclusiveQueues定義了queues、index、activeKeys屬性
New
tempo/pkg/flushqueues/exclusivequeues.go
// New creates a new set of flush queues with a prom gauge to track current depth
func New(queues int, metric prometheus.Gauge) *ExclusiveQueues {
f := &ExclusiveQueues{
queues: make([]*util.PriorityQueue, queues),
index: atomic.NewInt32(0),
}
for j := 0; j < queues; j++ {
f.queues[j] = util.NewPriorityQueue(metric)
}
return f
}
New方法先創建ExclusiveQueues,然後根據指定的queue個數通過util.NewPriorityQueue(metric)創建PriorityQueue
Enqueue
tempo/pkg/flushqueues/exclusivequeues.go
// Enqueue adds the op to the next queue and prevents any other items to be added with this key
func (f *ExclusiveQueues) Enqueue(op util.Op) {
_, ok := f.activeKeys.Load(op.Key())
if ok {
return
}
f.activeKeys.Store(op.Key(), struct{}{})
f.Requeue(op)
}
Enqueue方法先從activeKeys查找指定的key,若已經存在則提前返回,不存在則放入activeKeys中,然後執行f.Requeue(op)
Requeue
tempo/pkg/flushqueues/exclusivequeues.go
// Requeue adds an op that is presumed to already be covered by activeKeys
func (f *ExclusiveQueues) Requeue(op util.Op) {
flushQueueIndex := int(f.index.Inc()) % len(f.queues)
f.queues[flushQueueIndex].Enqueue(op)
}
Requeue方法首先通過
int(f.index.Inc()) % len(f.queues)
計算flushQueueIndex,然後找到對應的queue,執行Enqueue方法
Dequeue
tempo/pkg/flushqueues/exclusivequeues.go
// Dequeue removes the next op from the requested queue. After dequeueing the calling
// process either needs to call ClearKey or Requeue
func (f *ExclusiveQueues) Dequeue(q int) util.Op {
return f.queues[q].Dequeue()
}
Dequeue方法執行f.queues[q]對應queue的Dequeue
Clear
tempo/pkg/flushqueues/exclusivequeues.go
// Clear unblocks the requested op. This should be called only after a flush has been successful
func (f *ExclusiveQueues) Clear(op util.Op) {
f.activeKeys.Delete(op.Key())
}
Clear方法將指定key從activeKeys中移除
Stop
tempo/pkg/flushqueues/exclusivequeues.go
// Stop closes all queues
func (f *ExclusiveQueues) Stop() {
for _, q := range f.queues {
q.Close()
}
}
Stop方法遍歷f.queues,挨個執行q.Close()
小結
tempo的ExclusiveQueues定義了queues、index、activeKeys屬性;它提供了Enqueue、Requeue、Dequeue、Clear、Stop方法。