blob: 68730139a73a7e25eb6e9c2b2040099a52de3a39 [file] [log] [blame]
package metrics
import (
"bufio"
"fmt"
"log"
"net"
"strings"
"time"
)
const (
// We force flush the statsite metrics after this period of
// inactivity. Prevents stats from getting stuck in a buffer
// forever.
flushInterval = 100 * time.Millisecond
)
// StatsiteSink provides a MetricSink that can be used with a
// statsite metrics server
type StatsiteSink struct {
addr string
metricQueue chan string
}
// NewStatsiteSink is used to create a new StatsiteSink
func NewStatsiteSink(addr string) (*StatsiteSink, error) {
s := &StatsiteSink{
addr: addr,
metricQueue: make(chan string, 4096),
}
go s.flushMetrics()
return s, nil
}
// Close is used to stop flushing to statsite
func (s *StatsiteSink) Shutdown() {
close(s.metricQueue)
}
func (s *StatsiteSink) SetGauge(key []string, val float32) {
flatKey := s.flattenKey(key)
s.pushMetric(fmt.Sprintf("%s:%f|g\n", flatKey, val))
}
func (s *StatsiteSink) EmitKey(key []string, val float32) {
flatKey := s.flattenKey(key)
s.pushMetric(fmt.Sprintf("%s:%f|kv\n", flatKey, val))
}
func (s *StatsiteSink) IncrCounter(key []string, val float32) {
flatKey := s.flattenKey(key)
s.pushMetric(fmt.Sprintf("%s:%f|c\n", flatKey, val))
}
func (s *StatsiteSink) AddSample(key []string, val float32) {
flatKey := s.flattenKey(key)
s.pushMetric(fmt.Sprintf("%s:%f|ms\n", flatKey, val))
}
// Flattens the key for formatting, removes spaces
func (s *StatsiteSink) flattenKey(parts []string) string {
joined := strings.Join(parts, ".")
return strings.Map(func(r rune) rune {
switch r {
case ':':
fallthrough
case ' ':
return '_'
default:
return r
}
}, joined)
}
// Does a non-blocking push to the metrics queue
func (s *StatsiteSink) pushMetric(m string) {
select {
case s.metricQueue <- m:
default:
}
}
// Flushes metrics
func (s *StatsiteSink) flushMetrics() {
var sock net.Conn
var err error
var wait <-chan time.Time
var buffered *bufio.Writer
ticker := time.NewTicker(flushInterval)
defer ticker.Stop()
CONNECT:
// Attempt to connect
sock, err = net.Dial("tcp", s.addr)
if err != nil {
log.Printf("[ERR] Error connecting to statsite! Err: %s", err)
goto WAIT
}
// Create a buffered writer
buffered = bufio.NewWriter(sock)
for {
select {
case metric, ok := <-s.metricQueue:
// Get a metric from the queue
if !ok {
goto QUIT
}
// Try to send to statsite
_, err := buffered.Write([]byte(metric))
if err != nil {
log.Printf("[ERR] Error writing to statsite! Err: %s", err)
goto WAIT
}
case <-ticker.C:
if err := buffered.Flush(); err != nil {
log.Printf("[ERR] Error flushing to statsite! Err: %s", err)
goto WAIT
}
}
}
WAIT:
// Wait for a while
wait = time.After(time.Duration(5) * time.Second)
for {
select {
// Dequeue the messages to avoid backlog
case _, ok := <-s.metricQueue:
if !ok {
goto QUIT
}
case <-wait:
goto CONNECT
}
}
QUIT:
s.metricQueue = nil
}