mirror of
https://github.com/prometheus/prometheus.git
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97 lines
2.9 KiB
Go
97 lines
2.9 KiB
Go
/*
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Copyright 2015 The Kubernetes Authors.
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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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http://www.apache.org/licenses/LICENSE-2.0
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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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*/
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package trace
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import (
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"bytes"
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"fmt"
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"math/rand"
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"time"
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"k8s.io/klog"
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)
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type traceStep struct {
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stepTime time.Time
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msg string
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}
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// Trace keeps track of a set of "steps" and allows us to log a specific
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// step if it took longer than its share of the total allowed time
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type Trace struct {
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name string
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startTime time.Time
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steps []traceStep
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}
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// New creates a Trace with the specified name
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func New(name string) *Trace {
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return &Trace{name, time.Now(), nil}
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}
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// Step adds a new step with a specific message
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func (t *Trace) Step(msg string) {
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if t.steps == nil {
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// traces almost always have less than 6 steps, do this to avoid more than a single allocation
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t.steps = make([]traceStep, 0, 6)
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}
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t.steps = append(t.steps, traceStep{time.Now(), msg})
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}
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// Log is used to dump all the steps in the Trace
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func (t *Trace) Log() {
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// an explicit logging request should dump all the steps out at the higher level
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t.logWithStepThreshold(0)
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}
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func (t *Trace) logWithStepThreshold(stepThreshold time.Duration) {
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var buffer bytes.Buffer
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tracenum := rand.Int31()
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endTime := time.Now()
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totalTime := endTime.Sub(t.startTime)
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buffer.WriteString(fmt.Sprintf("Trace[%d]: %q (started: %v) (total time: %v):\n", tracenum, t.name, t.startTime, totalTime))
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lastStepTime := t.startTime
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for _, step := range t.steps {
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stepDuration := step.stepTime.Sub(lastStepTime)
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if stepThreshold == 0 || stepDuration > stepThreshold || klog.V(4) {
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buffer.WriteString(fmt.Sprintf("Trace[%d]: [%v] [%v] %v\n", tracenum, step.stepTime.Sub(t.startTime), stepDuration, step.msg))
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}
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lastStepTime = step.stepTime
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}
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stepDuration := endTime.Sub(lastStepTime)
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if stepThreshold == 0 || stepDuration > stepThreshold || klog.V(4) {
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buffer.WriteString(fmt.Sprintf("Trace[%d]: [%v] [%v] END\n", tracenum, endTime.Sub(t.startTime), stepDuration))
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}
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klog.Info(buffer.String())
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}
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// LogIfLong is used to dump steps that took longer than its share
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func (t *Trace) LogIfLong(threshold time.Duration) {
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if time.Since(t.startTime) >= threshold {
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// if any step took more than it's share of the total allowed time, it deserves a higher log level
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stepThreshold := threshold / time.Duration(len(t.steps)+1)
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t.logWithStepThreshold(stepThreshold)
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}
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}
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// TotalTime can be used to figure out how long it took since the Trace was created
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func (t *Trace) TotalTime() time.Duration {
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return time.Since(t.startTime)
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}
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