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redis_exporter.go
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/
redis_exporter.go
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package main
import (
"flag"
// "fmt"
"log"
"net/http"
"strconv"
"strings"
"sync"
"time"
"github.com/garyburd/redigo/redis"
"github.com/prometheus/client_golang/prometheus"
)
var (
redisAddr = flag.String("redis.addr", "localhost:6379", "Address of one or more redis nodes, comma separated")
namespace = flag.String("namespace", "redis", "Namespace for metrics")
listenAddress = flag.String("web.listen-address", ":9121", "Address to listen on for web interface and telemetry.")
metricPath = flag.String("web.telemetry-path", "/metrics", "Path under which to expose metrics.")
)
type Exporter struct {
addrs []string
namespace string
duration prometheus.Gauge
scrapeErrors prometheus.Gauge
totalScrapes prometheus.Counter
metrics map[string]*prometheus.GaugeVec
sync.RWMutex
}
type scrapeResult struct {
Name string
Value float64
Addr string
DB string
}
func (e *Exporter) initGauges() {
e.metrics = map[string]*prometheus.GaugeVec{}
e.metrics["db_keys_total"] = prometheus.NewGaugeVec(prometheus.GaugeOpts{
Namespace: e.namespace,
Name: "db_keys_total",
Help: "Total number of keys by DB",
}, []string{"addr", "db"})
e.metrics["db_expiring_keys_total"] = prometheus.NewGaugeVec(prometheus.GaugeOpts{
Namespace: e.namespace,
Name: "db_expiring_keys_total",
Help: "Total number of expiring keys by DB",
}, []string{"addr", "db"})
e.metrics["db_avg_ttl_seconds"] = prometheus.NewGaugeVec(prometheus.GaugeOpts{
Namespace: e.namespace,
Name: "db_avg_ttl_seconds",
Help: "Avg TTL in seconds",
}, []string{"addr", "db"})
}
func NewRedisExporter(addrs []string, namespace string) *Exporter {
e := Exporter{
addrs: addrs,
namespace: namespace,
duration: prometheus.NewGauge(prometheus.GaugeOpts{
Namespace: namespace,
Name: "exporter_last_scrape_duration_seconds",
Help: "The last scrape duration.",
}),
totalScrapes: prometheus.NewCounter(prometheus.CounterOpts{
Namespace: namespace,
Name: "exporter_scrapes_total",
Help: "Current total redis scrapes.",
}),
scrapeErrors: prometheus.NewGauge(prometheus.GaugeOpts{
Namespace: namespace,
Name: "exporter_last_scrape_error",
Help: "The last scrape error status.",
}),
}
e.initGauges()
return &e
}
func (e *Exporter) Describe(ch chan<- *prometheus.Desc) {
for _, m := range e.metrics {
m.Describe(ch)
}
ch <- e.duration.Desc()
ch <- e.totalScrapes.Desc()
ch <- e.scrapeErrors.Desc()
}
func (e *Exporter) Collect(ch chan<- prometheus.Metric) {
scrapes := make(chan scrapeResult)
e.Lock()
defer e.Unlock()
e.initGauges()
go e.scrape(scrapes)
e.setMetrics(scrapes)
ch <- e.duration
ch <- e.totalScrapes
ch <- e.scrapeErrors
e.collectMetrics(ch)
}
func includeMetric(name string) bool {
incl := map[string]bool{
"uptime_in_seconds": true,
"connected_clients": true,
"blocked_clients": true,
"used_memory": true,
"used_memory_rss": true,
"used_memory_peak": true,
"used_memory_lua": true,
"mem_fragmentation_ratio": true,
"total_connections_received": true,
"total_commands_processed": true,
"instantaneous_ops_per_sec": true,
"total_net_input_bytes": true,
"total_net_output_bytes": true,
"rejected_connections": true,
"expired_keys": true,
"evicted_keys": true,
"keyspace_hits": true,
"keyspace_misses": true,
"pubsub_channels": true,
"pubsub_patterns": true,
"connected_slaves": true,
"used_cpu_sys": true,
"used_cpu_user": true,
"used_cpu_sys_children": true,
"used_cpu_user_children": true,
"repl_backlog_size": true,
}
if strings.HasPrefix(name, "db") {
return true
}
_, ok := incl[name]
return ok
}
func extractMetrics(info, addr string, scrapes chan<- scrapeResult) error {
lines := strings.Split(info, "\r\n")
for _, line := range lines {
if (len(line) < 2) || line[0] == '#' || (!strings.Contains(line, ":")) {
continue
}
split := strings.Split(line, ":")
if len(split) != 2 || !includeMetric(split[0]) {
continue
}
if strings.HasPrefix(split[0], "db") {
// example: db0:keys=1,expires=0,avg_ttl=0
db := split[0]
stats := split[1]
split := strings.Split(stats, ",")
if len(split) != 3 {
log.Printf("wtf stats: %s", stats)
continue
}
extract := func(s string) (val float64) {
split := strings.Split(s, "=")
if len(split) != 2 {
log.Printf("couldn't split %s", s)
return 0
}
val, err := strconv.ParseFloat(split[1], 64)
if err != nil {
log.Printf("couldn't parse %s, err: %s", split[1], err)
}
return
}
scrapes <- scrapeResult{Name: "db_keys_total", Addr: addr, DB: db, Value: extract(split[0])}
scrapes <- scrapeResult{Name: "db_expiring_keys_total", Addr: addr, DB: db, Value: extract(split[1])}
scrapes <- scrapeResult{Name: "db_avg_ttl_seconds", Addr: addr, DB: db, Value: (extract(split[2]) / 1000)}
continue
}
val, err := strconv.ParseFloat(split[1], 64)
if err != nil {
log.Printf("couldn't parse %s, err: %s", split[1], err)
continue
}
scrapes <- scrapeResult{Name: split[0], Addr: addr, Value: val}
}
return nil
}
func (e *Exporter) scrape(scrapes chan<- scrapeResult) {
defer close(scrapes)
now := time.Now().UnixNano()
e.totalScrapes.Inc()
//var err error
errorCount := 0
for _, addr := range e.addrs {
// log.Printf("opening connection to redis node %s", addr)
c, err := redis.Dial("tcp", addr)
if err != nil {
log.Printf("redis err: %s", err)
errorCount++
continue
}
info, err := redis.String(c.Do("INFO"))
c.Close()
if err != nil {
log.Printf("redis err: %s", err)
errorCount++
continue
}
if err := extractMetrics(info, addr, scrapes); err != nil {
log.Printf("redis err: %s", err)
errorCount++
}
}
// log.Printf("redis errors: %d err: %s", errorCount, err)
e.scrapeErrors.Set(float64(errorCount))
e.duration.Set(float64(time.Now().UnixNano()-now) / 1000000000)
}
func (e *Exporter) setMetrics(scrapes <-chan scrapeResult) {
for scr := range scrapes {
name := scr.Name
if _, ok := e.metrics[name]; !ok {
e.metrics[name] = prometheus.NewGaugeVec(prometheus.GaugeOpts{
Namespace: e.namespace,
Name: name,
}, []string{"addr"})
}
var labels prometheus.Labels = map[string]string{"addr": scr.Addr}
if len(scr.DB) > 0 {
labels["db"] = scr.DB
}
e.metrics[name].With(labels).Set(float64(scr.Value))
}
}
func (e *Exporter) collectMetrics(metrics chan<- prometheus.Metric) {
for _, m := range e.metrics {
m.Collect(metrics)
}
}
func main() {
flag.Parse()
addrs := strings.Split(*redisAddr, ",")
if len(addrs) == 0 || len(addrs[0]) == 0 {
log.Fatal("Invalid parameter --redis.addr")
}
e := NewRedisExporter(addrs, *namespace)
prometheus.MustRegister(e)
http.Handle(*metricPath, prometheus.Handler())
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
w.Write([]byte(`<html>
<head><title>Redis exporter</title></head>
<body>
<h1>Redis exporter</h1>
<p><a href='` + *metricPath + `'>Metrics</a></p>
</body>
</html>
`))
})
log.Printf("providing metrics at %s%s", *listenAddress, *metricPath)
log.Printf("Connecting to: %#v", addrs)
log.Fatal(http.ListenAndServe(*listenAddress, nil))
}