Moves redis list items from a source list to a target list one item at a time. Useful if you use lists as queues and can't rename the key because that would wipe out items in the target queue.

main.go

package main

import (
	"flag"
	"log"
	"menteslibres.net/gosexy/redis"
	"os"
	"os/signal"
	"time"
)

func main() {
	source := flag.String("source", "", "source redis list")
	target := flag.String("target", "", "target redis list")
	limit := flag.Int("limit", 0, "max number of items to move")
	flag.Parse()

	if *source == "" || *target == "" {
		flag.PrintDefaults()
		os.Exit(1)
	}

	// capture ctrl+c and exit (useful if we later want to ensure we don't die inbetween an op)
	c := make(chan os.Signal, 1)
	signal.Notify(c, os.Interrupt)
	go func() {
		for sig := range c {
			log.Printf("captured %v, exiting..", sig)
			os.Exit(1)
		}
	}()

	client := getClient()
	count := 0

	for {
		if *limit > 0 && count >= *limit {
			log.Printf("Limit of %d reached, exiting", *limit)
			break
		}
		if count%100 == 0 {
			log.Println(count)
		}
		data, err := client.LPop(*source)
		if err != nil {
			log.Fatalf("LPop failed %s\n", err.Error())
			os.Exit(1)
		}

		if data == "" {
			log.Println("No more data")
			break
		}

		client.LPush(*target, data)
		count = count + 1

		// sleep to throttle how fast we move from one list to the other
		time.Sleep(time.Millisecond * 2)
	}

	log.Printf("finished moving %d items from %s to %s", count, *source, *target)
}

func getClient() *redis.Client {
	client := redis.New()
	err := client.Connect("127.0.0.1", 6379)

	if err != nil {
		log.Fatalf("Connect failed: %s\n", err.Error())
		return nil
	}

	return client
}