75 lines
2.2 KiB
Go
75 lines
2.2 KiB
Go
// Copyright The OpenTelemetry Authors
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// Copyright 2017, OpenCensus Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package zpages
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import (
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"time"
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sdktrace "go.opentelemetry.io/otel/sdk/trace"
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)
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const (
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// defaultBucketCapacity is the default capacity for every bucket (latency or error based).
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defaultBucketCapacity = 10
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// samplePeriod is the minimum time between accepting spans in a single bucket.
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samplePeriod = time.Second
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)
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// bucket is a container for a set of spans for latency buckets or errored spans.
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type bucket struct {
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nextTime time.Time // next time we can accept a span
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buffer []sdktrace.ReadOnlySpan // circular buffer of spans
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nextIndex int // location next ReadOnlySpan should be placed in buffer
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overflow bool // whether the circular buffer has wrapped around
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}
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// newBucket returns a new bucket with the given capacity.
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func newBucket(capacity uint) *bucket {
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return &bucket{
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buffer: make([]sdktrace.ReadOnlySpan, capacity),
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}
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}
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// add adds a span to the bucket, if nextTime has been reached.
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func (b *bucket) add(s sdktrace.ReadOnlySpan) {
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if s.EndTime().Before(b.nextTime) {
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return
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}
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if len(b.buffer) == 0 {
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return
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}
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b.nextTime = s.EndTime().Add(samplePeriod)
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b.buffer[b.nextIndex] = s
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b.nextIndex++
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if b.nextIndex == len(b.buffer) {
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b.nextIndex = 0
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b.overflow = true
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}
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}
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// len returns the number of spans in the bucket.
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func (b *bucket) len() int {
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if b.overflow {
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return len(b.buffer)
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}
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return b.nextIndex
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}
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// spans returns the spans in this bucket.
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func (b *bucket) spans() []sdktrace.ReadOnlySpan {
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return append([]sdktrace.ReadOnlySpan(nil), b.buffer[0:b.len()]...)
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}
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