GoStats

Simple Stats for Go Services

At Green Man Gaming we have a large number of services that run and we have a requirement to monitor them all.

To do this we rely on have stats we can cURL out. We have this for Scala via Ostrich from the guys over at Twitter. However, for Google Go we needed something similar and couldn't find something suitable.

GoStats was born.

go get github.com/greenmangaming/gostats

Three types of metrics are supported:

1. Counters
2. Labels
3. Timers (count, sum, averages and percentiles)

Usage

Let's take the default example from Writing Web Applications of a very simple Go Http Server:

package main

import (
  "fmt"
  "net/http"
)

func handler(w http.ResponseWriter, r *http.Request) {
  fmt.Fprintf(w, "Hi there, I love %s!", r.URL.Path[1:])
}

func main() {
  http.HandleFunc("/", handler)
  http.ListenAndServe(":8080", nil)
}

Let's do the same things with Stats:

package main

import (
  "fmt"
  "net/http"

  "github.com/greenmangaming/gostats"
)

func handler(w http.ResponseWriter, r *http.Request) {
  gostats.Stats.Time("root", func() {
    fmt.Fprintf(w, "Hi there, I love %s!", r.URL.Path[1:])
  })
}

func main() {
  gostats.Stats.Addr = ":8081"
  go gostats.Stats.ListenAndServe()

  http.HandleFunc("/", handler)
  http.ListenAndServe(":8080", nil)
}

That's it!

Compile/run and do curl http://localhost:8080/Lee and then curl http://localhost:8081/stats:

➜  ~  curl http://localhost:8080/Lee
Hi there, I love Lee!%
➜  ~  curl http://localhost:8081/stats
{"counters":{},"labels":{},"metrics":{"root":{"avg":19959,"count":1,"p25":19959,
"p5":19959,"p75":19959,"p9":19959,"p95":19959,"p99":19959,"p999":19959,"p9999":19959,
"sum":19959}}}%

Timings are reported in Nanoseconds.

Counters

Counters are just that. They count every call. I recommend using this as a goroutine:

go gostats.Stats.IncrementCounter("gophers")

Labels

Labels are very basic and just allow you to set the current status of something:

go gostats.Stats.Label("groundhog_day", "yes")

Timers

Timers are a little bit more involved than the other types. An example of the usage of it is above.