forked from mirror/client_golang
75 lines
2.4 KiB
Go
75 lines
2.4 KiB
Go
// Copyright 2016 The Prometheus Authors
|
|
// 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 prometheus
|
|
|
|
import "time"
|
|
|
|
// Observer is the interface that wraps the Observe method, which is used by
|
|
// Histogram and Summary to add observations.
|
|
type Observer interface {
|
|
Observe(float64)
|
|
}
|
|
|
|
// The ObserverFunc type is an adapter to allow the use of ordinary
|
|
// functions as Observers. If f is a function with the appropriate
|
|
// signature, ObserverFunc(f) is an Observer that calls f.
|
|
//
|
|
// This adapter is usually used in connection with the Timer type, and there are
|
|
// two general use cases:
|
|
//
|
|
// The most common one is to use a Gauge as the Observer for a Timer.
|
|
// See the "Gauge" Timer example.
|
|
//
|
|
// The more advanced use case is to create a function that dynamically decides
|
|
// which Observer to use for observing the duration. See the "Complex" Timer
|
|
// example.
|
|
type ObserverFunc func(float64)
|
|
|
|
// Observe calls f(value). It implements Observer.
|
|
func (f ObserverFunc) Observe(value float64) {
|
|
f(value)
|
|
}
|
|
|
|
// Timer is a helper type to time functions. Use NewTimer to create new
|
|
// instances.
|
|
type Timer struct {
|
|
begin time.Time
|
|
observer Observer
|
|
}
|
|
|
|
// NewTimer creates a new Timer. The provided Observer is used to observe a
|
|
// duration in seconds. Timer is usually used to time a function call in the
|
|
// following way:
|
|
// func TimeMe() {
|
|
// timer := NewTimer(myHistogram)
|
|
// defer timer.ObserveDuration()
|
|
// // Do actual work.
|
|
// }
|
|
func NewTimer(o Observer) *Timer {
|
|
return &Timer{
|
|
begin: time.Now(),
|
|
observer: o,
|
|
}
|
|
}
|
|
|
|
// ObserveDuration records the duration passed since the Timer was created with
|
|
// NewTimer. It calls the Observe method of the Observer provided during
|
|
// construction with the duration in seconds as an argument. ObserveDuration is
|
|
// usually called with a defer statement.
|
|
func (t *Timer) ObserveDuration() {
|
|
if t.observer != nil {
|
|
t.observer.Observe(time.Since(t.begin).Seconds())
|
|
}
|
|
}
|