Script that runs in the background and tells you when ElasticSearch migration/cluster has stabilised. Requires the "say" command that exists on MaxOSX.

tell-me-when-elasticsearch-is-done.go

package main

import (
	"encoding/json"
	"fmt"
	"log"
	"net/http"
	"os"
	"os/exec"
	"time"
)

func say(s string) {
	exec.Command("say", s).Run()
}

type Health struct {
	Status             string `json:"status"`
	RelocatingShards   int    `json:"relocating_shards"`
	InitializingShards int    `json:"initializing_shards"`
}

func (h Health) String() string {
	return fmt.Sprintf("{Status: %s, RelocatingShards: %d, InitializingShards: %d}", h.Status, h.RelocatingShards, h.InitializingShards)
}

func getHealth(ip string) Health {
	s := &Health{}
	resp, err := http.Get(fmt.Sprintf("http://%s:9200/_cluster/health?pretty", ip))
	if err != nil {
		log.Fatalln(err)
	}
	defer resp.Body.Close()

	d := json.NewDecoder(resp.Body)
	err = d.Decode(s)
	if err != nil {
		log.Fatalln(err)
	}

	return *s
}

func main() {
	if len(os.Args) != 2 {
		log.Fatalln("Usage: ./tell-me-when-elasticsearch-is-done <ip>")
	}
	ip := os.Args[1]

	say("Starting to poll elastic search. I'll let you know when status is red or green.")

	for {
		health := getHealth(ip)

		log.Println(health)

		toSay := "Elastic search "

		switch health.Status {
		case "red":
			toSay = "status is red"
		case "green":
			toSay = "status is green"
		}

		if health.RelocatingShards > 0 {
			if toSay != "" {
				toSay += " and it "
			}
			toSay += "is still relocating"
		}
		if health.InitializingShards > 0 {
			if toSay != "" {
				toSay += " and it "
			}
			toSay += "is still initializing"
		}

		say(toSay)

		time.Sleep(5 * time.Minute)
	}

}