recorders.go

/*
Copyright 2014-2016 Pinterest, Inc.

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 bender

import (
	"log"

	"github.com/pinterest/bender/hist"
)

// A Recorder records a message.
type Recorder func(interface{})

// Record records messages from a channel using the given recorders.
func Record(c chan interface{}, recorders ...Recorder) {
	for msg := range c {
		for _, recorder := range recorders {
			recorder(msg)
		}
	}
}

func logMessage(l *log.Logger, msg interface{}) {
	l.Printf("%+v", msg)
}

// NewLoggingRecorder creates a new log.Logger-based recorder.
func NewLoggingRecorder(l *log.Logger) Recorder {
	return func(msg interface{}) {
		logMessage(l, msg)
	}
}

// NewHistogramRecorder creates a new hist.Histogram-based recorder.
func NewHistogramRecorder(h *hist.Histogram) Recorder {
	return func(msg interface{}) {
		switch msg := msg.(type) {
		case *StartEvent:
			h.Start(int(msg.Start))
		case *EndEvent:
			h.End(int(msg.End))
		case *EndRequestEvent:
			elapsed := int(msg.End - msg.Start)
			if msg.Err == nil {
				h.Add(elapsed)
			} else {
				h.AddError(elapsed)
			}
		}
	}
}