| // 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" |
| |
| // 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. The observed |
| // duration is also returned. ObserveDuration is usually called with a defer |
| // statement. |
| // |
| // Note that this method is only guaranteed to never observe negative durations |
| // if used with Go1.9+. |
| func (t *Timer) ObserveDuration() time.Duration { |
| d := time.Since(t.begin) |
| if t.observer != nil { |
| t.observer.Observe(d.Seconds()) |
| } |
| return d |
| } |