Etherpad Migration from Redis to MySQL

redis_to_mysql.go

package main

import (
	"database/sql"
	"flag"
	"fmt"
	"log"
	"strings"

	"github.com/go-redis/redis"
	_ "github.com/go-sql-driver/mysql"
	"gopkg.in/cheggaaa/pb.v1"
)

var (
	redisHost string
	redisPort string
	mysqlUser string
	mysqlPass string
	mysqlDb   string
	mysqlHost string
	mysqlPort string
	dryRun    bool
)

func main() {
	flag.StringVar(&redisHost, "redis-host", "localhost", "redis host")
	flag.StringVar(&redisPort, "redis-port", "6379", "redis port")
	flag.StringVar(&mysqlUser, "mysql-user", "etherpad", "mysql user")
	flag.StringVar(&mysqlPass, "mysql-pass", "etherpad", "mysql password")
	flag.StringVar(&mysqlDb, "mysql-db", "etherpad", "mysql database")
	flag.StringVar(&mysqlHost, "mysql-host", "127.0.0.1", "mysql host")
	flag.StringVar(&mysqlPort, "mysql-port", "3306", "mysql port")
	flag.BoolVar(&dryRun, "dry-run", false, "dry-run")
	flag.Parse()

	db := redis.NewClient(&redis.Options{
		Addr: fmt.Sprintf("%s:%s", redisHost, redisPort),
		DB:   0,
	})
	defer db.Close()

	my, err := sql.Open("mysql", fmt.Sprintf("%s:%s@tcp(%s:%s)/%s", mysqlUser, mysqlPass, mysqlHost, mysqlPort, mysqlDb))
	if err != nil {
		panic(err)
	}
	defer my.Close()

	val, err := db.DbSize().Result()
	if err != nil {
		panic(err)
	}

	fmt.Printf("Total keys to process: %d\n", val)
	bar := pb.StartNew(int(val))
	bar.ShowTimeLeft = true
	bar.ShowSpeed = true

	var c uint64
	var keys []string

	for ok := true; ok; {
		keys, c, err = db.Scan(c, "", 0).Result()
		if err != nil {
			panic(err)
		}

		for _, key := range keys {
			bar.Increment()
			// Ignore keys prefixed with ueberDB (not needed in MySQL)
			if strings.HasPrefix(key, "ueberDB") {
				continue
			}

			// Ignore keys prefixed with mylist (not needed in MySQL)
			if strings.HasPrefix(key, "mylist") {
				continue
			}

			val, err := db.Get(key).Result()
			if err != nil {
				log.Printf("Error: %s is not valid key for scalar value. Message: %s\n", key, err)
				continue
			}

			if !dryRun {
				stmt, err := my.Prepare("INSERT INTO store VALUES (?,?)")
				if err != nil {
					panic(err)
				}

				_, err = stmt.Exec(key, val)
				if err != nil {
					panic(err)
				}

				err = stmt.Close()
				if err != nil {
					panic(err)
				}
			}
		}

		if c == 0 {
			ok = false
		}
	}

	bar.Finish()
}