56 lines
1.4 KiB
Go
56 lines
1.4 KiB
Go
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// Copyright (c) 2012, Matt T. Proud
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// All rights reserved.
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//
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// timer.go provides a scalar metric that times how long a given event takes.
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package metrics
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import (
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"time"
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)
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// This callback is called upon the completion of the timer—i.e., when it stops.
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type CompletionCallback func(duration time.Duration)
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// This is meant to capture a function that a StopWatch can call for purposes
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// of instrumentation.
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type InstrumentableCall func()
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type StopWatch struct {
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startTime time.Time
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endTime time.Time
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onCompletion CompletionCallback
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}
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// Return a new StopWatch that is ready for instrumentation.
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func Start(onCompletion CompletionCallback) *StopWatch {
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return &StopWatch{
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startTime: time.Now(),
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onCompletion: onCompletion,
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}
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}
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// Stop the StopWatch returning the elapsed duration of its lifetime while
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// firing an optional CompletionCallback in the background.
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func (s *StopWatch) Stop() time.Duration {
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s.endTime = time.Now()
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duration := s.endTime.Sub(s.startTime)
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if s.onCompletion != nil {
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go s.onCompletion(duration)
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}
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return duration
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}
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// Provide a quick way of instrumenting a InstrumentableCall and emitting its
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// duration.
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func InstrumentCall(instrumentable InstrumentableCall, onCompletion CompletionCallback) time.Duration {
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s := Start(onCompletion)
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instrumentable()
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return s.Stop()
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}
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