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本文次要钻研一下tempo的ExclusiveQueues

ExclusiveQueues

tempo/pkg/flushqueues/exclusivequeues.go

type ExclusiveQueues struct {    queues     []*util.PriorityQueue    index      *atomic.Int32    activeKeys sync.Map}
ExclusiveQueues定义了queues、index、activeKeys属性

New

tempo/pkg/flushqueues/exclusivequeues.go

// New creates a new set of flush queues with a prom gauge to track current depthfunc 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办法先创立ExclusiveQueues，而后依据指定的queue个数通过util.NewPriorityQueue(metric)创立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 keyfunc (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办法先从activeKeys查找指定的key，若曾经存在则提前返回，不存在则放入activeKeys中，而后执行f.Requeue(op)

Requeue

tempo/pkg/flushqueues/exclusivequeues.go

// Requeue adds an op that is presumed to already be covered by activeKeysfunc (f *ExclusiveQueues) Requeue(op util.Op) {    flushQueueIndex := int(f.index.Inc()) % len(f.queues)    f.queues[flushQueueIndex].Enqueue(op)}
Requeue办法首先通过int(f.index.Inc()) % len(f.queues)计算flushQueueIndex，而后找到对应的queue，执行Enqueue办法

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 Requeuefunc (f *ExclusiveQueues) Dequeue(q int) util.Op {    return f.queues[q].Dequeue()}
Dequeue办法执行f.queues[q]对应queue的Dequeue

Clear

tempo/pkg/flushqueues/exclusivequeues.go

// Clear unblocks the requested op.  This should be called only after a flush has been successfulfunc (f *ExclusiveQueues) Clear(op util.Op) {    f.activeKeys.Delete(op.Key())}
Clear办法将指定key从activeKeys中移除

Stop

tempo/pkg/flushqueues/exclusivequeues.go

// Stop closes all queuesfunc (f *ExclusiveQueues) Stop() {    for _, q := range f.queues {        q.Close()    }}
Stop办法遍历f.queues，挨个执行q.Close()

小结

tempo的ExclusiveQueues定义了queues、index、activeKeys属性；它提供了Enqueue、Requeue、Dequeue、Clear、Stop办法。

doc

  • tempo