123 lines
3.0 KiB
Go
123 lines
3.0 KiB
Go
package internal
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import (
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"bytes"
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"container/heap"
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"github.com/newrelic/go-agent/internal/jsonx"
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)
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// eventStamp allows for uniform random sampling of events. When an event is
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// created it is given an eventStamp. Whenever an event pool is full and events
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// need to be dropped, the events with the lowest stamps are dropped.
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type eventStamp float32
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func eventStampCmp(a, b eventStamp) bool {
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return a < b
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}
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type analyticsEvent struct {
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stamp eventStamp
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jsonWriter
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}
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type analyticsEventHeap []analyticsEvent
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type analyticsEvents struct {
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numSeen int
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events analyticsEventHeap
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failedHarvests int
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}
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func (events *analyticsEvents) NumSeen() float64 { return float64(events.numSeen) }
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func (events *analyticsEvents) NumSaved() float64 { return float64(len(events.events)) }
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func (h analyticsEventHeap) Len() int { return len(h) }
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func (h analyticsEventHeap) Less(i, j int) bool { return eventStampCmp(h[i].stamp, h[j].stamp) }
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func (h analyticsEventHeap) Swap(i, j int) { h[i], h[j] = h[j], h[i] }
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// Push and Pop are unused: only heap.Init and heap.Fix are used.
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func (h analyticsEventHeap) Push(x interface{}) {}
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func (h analyticsEventHeap) Pop() interface{} { return nil }
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func newAnalyticsEvents(max int) *analyticsEvents {
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return &analyticsEvents{
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numSeen: 0,
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events: make(analyticsEventHeap, 0, max),
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failedHarvests: 0,
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}
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}
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func (events *analyticsEvents) addEvent(e analyticsEvent) {
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events.numSeen++
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if len(events.events) < cap(events.events) {
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events.events = append(events.events, e)
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if len(events.events) == cap(events.events) {
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// Delay heap initialization so that we can have
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// deterministic ordering for integration tests (the max
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// is not being reached).
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heap.Init(events.events)
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}
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return
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}
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if eventStampCmp(e.stamp, events.events[0].stamp) {
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return
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}
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events.events[0] = e
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heap.Fix(events.events, 0)
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}
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func (events *analyticsEvents) mergeFailed(other *analyticsEvents) {
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fails := other.failedHarvests + 1
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if fails >= failedEventsAttemptsLimit {
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return
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}
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events.failedHarvests = fails
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events.Merge(other)
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}
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func (events *analyticsEvents) Merge(other *analyticsEvents) {
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allSeen := events.numSeen + other.numSeen
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for _, e := range other.events {
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events.addEvent(e)
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}
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events.numSeen = allSeen
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}
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func (events *analyticsEvents) CollectorJSON(agentRunID string) ([]byte, error) {
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if 0 == events.numSeen {
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return nil, nil
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}
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estimate := 256 * len(events.events)
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buf := bytes.NewBuffer(make([]byte, 0, estimate))
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buf.WriteByte('[')
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jsonx.AppendString(buf, agentRunID)
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buf.WriteByte(',')
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buf.WriteByte('{')
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buf.WriteString(`"reservoir_size":`)
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jsonx.AppendUint(buf, uint64(cap(events.events)))
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buf.WriteByte(',')
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buf.WriteString(`"events_seen":`)
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jsonx.AppendUint(buf, uint64(events.numSeen))
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buf.WriteByte('}')
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buf.WriteByte(',')
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buf.WriteByte('[')
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for i, e := range events.events {
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if i > 0 {
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buf.WriteByte(',')
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}
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e.WriteJSON(buf)
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}
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buf.WriteByte(']')
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buf.WriteByte(']')
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return buf.Bytes(), nil
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}
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