prometheus/stats/timer.go

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// Copyright 2013 Prometheus Team
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package stats
import (
"bytes"
"fmt"
"sort"
"time"
)
// A Timer that can be started and stopped and accumulates the total time it
// was running (the time between Start() and Stop()).
type Timer struct {
name fmt.Stringer
created time.Time
start time.Time
duration time.Duration
}
// Start the timer.
func (t *Timer) Start() *Timer {
t.start = time.Now()
return t
}
// Stop the timer.
func (t *Timer) Stop() {
t.duration += time.Since(t.start)
}
// Return a string representation of the Timer.
func (t *Timer) String() string {
return fmt.Sprintf("%s: %s", t.name, t.duration)
}
// A TimerGroup represents a group of timers relevant to a single query.
type TimerGroup struct {
timers map[fmt.Stringer]*Timer
child *TimerGroup
}
// NewTimerGroup constructs a new TimerGroup.
func NewTimerGroup() *TimerGroup {
return &TimerGroup{timers: map[fmt.Stringer]*Timer{}}
}
// GetTimer gets (and creates, if necessary) the Timer for a given code section.
func (t *TimerGroup) GetTimer(name fmt.Stringer) *Timer {
if timer, exists := t.timers[name]; exists {
return timer
}
timer := &Timer{
name: name,
created: time.Now(),
}
t.timers[name] = timer
return timer
}
// Timers is a slice of Timer pointers that implements Len and Swap from
// sort.Interface.
type Timers []*Timer
type byCreationTimeSorter struct{ Timers }
// Len implements sort.Interface.
func (t Timers) Len() int {
return len(t)
}
// Swap implements sort.Interface.
func (t Timers) Swap(i, j int) {
t[i], t[j] = t[j], t[i]
}
func (s byCreationTimeSorter) Less(i, j int) bool {
return s.Timers[i].created.Before(s.Timers[j].created)
}
// Return a string representation of a TimerGroup.
func (t *TimerGroup) String() string {
timers := byCreationTimeSorter{}
for _, timer := range t.timers {
timers.Timers = append(timers.Timers, timer)
}
sort.Sort(timers)
result := &bytes.Buffer{}
for _, timer := range timers.Timers {
fmt.Fprintf(result, "%s\n", timer)
}
return result.String()
}