riemann.go

// Copyright (c) 2014 Ashley Jeffs
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, sub to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

package metrics

import (
	"fmt"
	"sync"
	"time"

	"github.com/amir/raidman"
)

//------------------------------------------------------------------------------

func init() {
	constructors["riemann"] = typeSpec{
		constructor: NewRiemann,
		description: `
Benthos can send metrics to Riemann as events, you can set your own tags but it
is recommended that you ensure the 'meter' tag is there to ensure they are dealt
with correctly within Riemann.`,
	}
}

//------------------------------------------------------------------------------

// RiemannConfig contains configuration fields for a riemann service.
type RiemannConfig struct {
	Server        string   `json:"server" yaml:"server"`
	TTL           float32  `json:"ttl" yaml:"ttl"`
	Tags          []string `json:"tags" yaml:"tags"`
	FlushInterval string   `json:"flush_interval" yaml:"flush_interval"`
}

// NewRiemannConfig creates a new riemann config with default values.
func NewRiemannConfig() RiemannConfig {
	return RiemannConfig{
		Server:        "",
		TTL:           5,
		Tags:          []string{"service", "meter"},
		FlushInterval: "2s",
	}
}

//------------------------------------------------------------------------------

// Riemann is a Riemann client that supports the Type interface.
type Riemann struct {
	sync.Mutex

	config Config

	flatMetrics map[string]int64

	Client      *raidman.Client
	eventsCache map[string]*raidman.Event

	flushInterval time.Duration
	quit          chan bool
}

// NewRiemann creates a new riemann client.
func NewRiemann(config Config) (Type, error) {
	interval, err := time.ParseDuration(config.Riemann.FlushInterval)
	if nil != err {
		return nil, fmt.Errorf("failed to parse flush interval: %v", err)
	}

	client, err := raidman.Dial("tcp", config.Riemann.Server)
	if err != nil {
		return nil, err
	}

	r := &Riemann{
		config:        config,
		Client:        client,
		flushInterval: interval,
		eventsCache:   make(map[string]*raidman.Event),
		quit:          make(chan bool),
	}

	go r.loop()

	return r, nil
}

//------------------------------------------------------------------------------

// Incr increments a stat by a value.
func (r *Riemann) Incr(stat string, value int64) error {
	r.Lock()
	defer r.Unlock()

	total, _ := r.flatMetrics[stat]
	total += value

	r.flatMetrics[stat] = total

	service := r.config.Prefix + stat
	r.eventsCache[service] = &raidman.Event{
		Ttl:     r.config.Riemann.TTL,
		Tags:    r.config.Riemann.Tags,
		Metric:  total,
		Service: service,
	}
	return nil
}

// Decr decrements a stat by a value.
func (r *Riemann) Decr(stat string, value int64) error {
	r.Lock()
	defer r.Unlock()

	total, _ := r.flatMetrics[stat]
	total -= value

	r.flatMetrics[stat] = total

	service := r.config.Prefix + stat
	r.eventsCache[service] = &raidman.Event{
		Ttl:     r.config.Riemann.TTL,
		Tags:    r.config.Riemann.Tags,
		Metric:  total,
		Service: service,
	}
	return nil
}

// Timing sets a stat representing a duration.
func (r *Riemann) Timing(stat string, delta int64) error {
	r.Lock()
	defer r.Unlock()

	service := r.config.Prefix + stat
	r.eventsCache[service] = &raidman.Event{
		Ttl:     r.config.Riemann.TTL,
		Tags:    r.config.Riemann.Tags,
		Metric:  delta,
		Service: service,
	}
	return nil
}

// Gauge sets a stat as a gauge value.
func (r *Riemann) Gauge(stat string, value int64) error {
	r.Lock()
	defer r.Unlock()

	service := r.config.Prefix + stat
	r.eventsCache[service] = &raidman.Event{
		Ttl:     r.config.Riemann.TTL,
		Tags:    r.config.Riemann.Tags,
		Metric:  value,
		Service: service,
	}
	return nil
}

// Close will close the riemann client and stop batch uploading.
func (r *Riemann) Close() error {
	close(r.quit)
	return nil
}

//------------------------------------------------------------------------------

func (r *Riemann) loop() {
	ticker := time.NewTicker(r.flushInterval)
	for {
		select {
		case <-ticker.C:
			r.flushMetrics()
		case <-r.quit:
			r.Client.Close()
			return
		}
	}
}

func (r *Riemann) flushMetrics() {
	r.Lock()
	defer r.Unlock()

	events := make([]*raidman.Event, len(r.eventsCache))
	i := 0
	for _, event := range r.eventsCache {
		events[i] = event
		i++
	}

	if err := r.Client.SendMulti(events); err == nil {
		r.eventsCache = make(map[string]*raidman.Event)
	} else {
		var newClient *raidman.Client
		newClient, err = raidman.DialWithTimeout("tcp", r.config.Riemann.Server, r.flushInterval)
		if err == nil {
			r.Client.Close()
			r.Client = newClient
		}
	}
}

//------------------------------------------------------------------------------