remove member from data directory

main.go

package main

import (
	"encoding/binary"
	"flag"
	"fmt"
	"log"
	"os"
	"path/filepath"
	"strings"
	"time"

	bolt "go.etcd.io/bbolt"
	"go.etcd.io/etcd/mvcc/mvccpb"
)

func snapDir(dataDir string) string {
	return filepath.Join(dataDir, "member", "snap")
}

func existFileOrDir(name string) bool {
	_, err := os.Stat(name)
	return err == nil
}

type decoder func(k, v []byte)

var decoders = map[string]decoder{
	"key": keyDecoder,
}

type revision struct {
	main int64
	sub  int64
}

func bytesToRev(bytes []byte) revision {
	return revision{
		main: int64(binary.BigEndian.Uint64(bytes[0:8])),
		sub:  int64(binary.BigEndian.Uint64(bytes[9:])),
	}
}

func keyDecoder(k, v []byte) {
	rev := bytesToRev(k)
	var kv mvccpb.KeyValue
	if err := kv.Unmarshal(v); err != nil {
		panic(err)
	}
	fmt.Printf("rev=%+v, value=[key %q | val %q | created %d | mod %d | ver %d]\n", rev, string(kv.Key), string(kv.Value), kv.CreateRevision, kv.ModRevision, kv.Version)
}

func iterateBucket(dbPath, bucket string, limit uint64, decode bool) (err error) {
	db, err := bolt.Open(dbPath, 0600, &bolt.Options{Timeout: 10 * time.Second})
	if err != nil {
		return fmt.Errorf("failed to open bolt DB %v", err)
	}
	defer db.Close()

	err = db.View(func(tx *bolt.Tx) error {
		b := tx.Bucket([]byte(bucket))
		if b == nil {
			return fmt.Errorf("got nil bucket for %s", bucket)
		}

		c := b.Cursor()

		// iterate in reverse order (use First() and Next() for ascending order)
		for k, v := c.Last(); k != nil; k, v = c.Prev() {
			// TODO: remove sensitive information
			// (https://github.com/etcd-io/etcd/issues/7620)
			if dec, ok := decoders[bucket]; decode && ok {
				dec(k, v)
			} else {
				fmt.Printf("key=%q, value=%q\n", k, v)
			}

			limit--
			if limit == 0 {
				break
			}
		}

		return nil
	})
	return err
}

// Find returns the smallest index i at which x == a[i],
// or len(a) if there is no such index.
func Find(a []string, x string) int {
	fmt.Println(x)
	for i, n := range a {
		if x == n {
			return i
		}
	}
	return len(a)
}

func removeIDs(dbPath, bucket string, ids []string) error {
	db, err := bolt.Open(dbPath, 0600, &bolt.Options{Timeout: 10 * time.Second})
	if err != nil {
		return fmt.Errorf("failed to open bolt DB %v", err)
	}
	defer db.Close()

	if bucket != "members" {
		return fmt.Errorf("can not remove member if this is not a member bucket")
	}

	tx, err := db.Begin(true)
	if err != nil {
		log.Printf("unable to open a writable transaction %v", err)
	}

	c := tx.Bucket([]byte(bucket)).Cursor()
	defer tx.Commit()

	// iterate in reverse order (use First() and Next() for ascending order)
	for k, v := c.First(); k != nil; k, v = c.Next() {
		// TODO: remove sensitive information
		// (https://github.com/etcd-io/etcd/issues/7620)
		index := Find(ids, string(k))
		fmt.Printf("Index %v\n", index)
		if index >= len(ids) {
			fmt.Printf("ignoring key %q: not to be deleted\n", k)
		}
		if index < len(ids) {
			fmt.Printf("deleteing key %v with value %v\n", k, v)
			if err := c.Delete(); err != nil {
				log.Printf("unable to delete %v: %v", k, err)
			}
		}
	}


	return err
}

var dataDir string
var remove_ids string

func main() {

	flag.StringVar(&dataDir, "data-dir", "/var/etcd/data", "Enter the filepath to etcd data directory")
	flag.StringVar(&remove_ids, "remove-ids", "", "[OPTIONAL] Enter the ids to be removed separated by ','")

	flag.Parse()

	if !strings.HasSuffix(dataDir, "db") {
		dataDir = filepath.Join(snapDir(dataDir), "db")
	}
	if !existFileOrDir(dataDir) {
		log.Fatalf("%q does not exist", dataDir)
	}

	err := iterateBucket(dataDir, "members", 0, true)
	if err != nil {
		log.Fatal(err)
	}
	err = iterateBucket(dataDir, "members_removed", 0, true)
	if err != nil {
		log.Fatal(err)
	}
	err = iterateBucket(dataDir, "cluster", 0, true)
	if err != nil {
		log.Fatal(err)
	}
	if remove_ids != "" {
		ids := strings.Split(remove_ids, ",")
		fmt.Printf("ids to be removed %v\n", ids)
		err := removeIDs(dataDir, "members", ids)
		if err != nil {
			log.Println(err)
		}
	}
}