telegraf/internal/buffer/buffer.go

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package buffer
import (
"sync"
"github.com/influxdata/telegraf"
"github.com/influxdata/telegraf/selfstat"
)
var (
MetricsWritten = selfstat.Register("agent", "metrics_written", map[string]string{})
MetricsDropped = selfstat.Register("agent", "metrics_dropped", map[string]string{})
)
// Buffer is an object for storing metrics in a circular buffer.
type Buffer struct {
buf chan telegraf.Metric
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mu sync.Mutex
}
// NewBuffer returns a Buffer
// size is the maximum number of metrics that Buffer will cache. If Add is
// called when the buffer is full, then the oldest metric(s) will be dropped.
func NewBuffer(size int) *Buffer {
return &Buffer{
buf: make(chan telegraf.Metric, size),
}
}
// IsEmpty returns true if Buffer is empty.
func (b *Buffer) IsEmpty() bool {
return len(b.buf) == 0
}
// Len returns the current length of the buffer.
func (b *Buffer) Len() int {
return len(b.buf)
}
// Add adds metrics to the buffer.
func (b *Buffer) Add(metrics ...telegraf.Metric) {
b.mu.Lock()
for i, _ := range metrics {
MetricsWritten.Incr(1)
select {
case b.buf <- metrics[i]:
default:
MetricsDropped.Incr(1)
<-b.buf
b.buf <- metrics[i]
}
}
b.mu.Unlock()
}
// Batch returns a batch of metrics of size batchSize.
// the batch will be of maximum length batchSize. It can be less than batchSize,
// if the length of Buffer is less than batchSize.
func (b *Buffer) Batch(batchSize int) []telegraf.Metric {
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b.mu.Lock()
n := min(len(b.buf), batchSize)
out := make([]telegraf.Metric, n)
for i := 0; i < n; i++ {
out[i] = <-b.buf
}
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b.mu.Unlock()
return out
}
func min(a, b int) int {
if b < a {
return b
}
return a
}