https://blog.alswl.com/2015/07/redis-migration/ Redis Cluster Migration

migrate_redis.py

# coding=utf-8

import sys
import time
import logging

import redis

logger = logging.getLogger(__name__)
logger.setLevel(logging.DEBUG)
handler = logging.StreamHandler(sys.stderr)
formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')
handler.setFormatter(formatter)
logger.addHandler(handler)

FROM_REDIS_HOST_PORT_DB = ('192.168.172.29', 6379, 5)
TO_REDIS_HOST_PORT_DB = ('192.168.172.46', 6379, 0)

EACH_SCAN_SIZE = 1000


def migrate_keys(from_redis, to_redis, keys):
    from_pipe = from_redis.pipeline(transaction=False)
    to_pipe = to_redis.pipeline(transaction=False)
    for key in keys:
        from_pipe.pttl(key)
        from_pipe.dump(key)
    res = from_pipe.execute()
    res_map = {x: (y[0], y[1]) for x, y in zip(keys, zip(res[::2], res[1::2]))}

    for key in keys:
        if res_map[key][0] == -2:
            logger.warning('x, old not exists, key: %s' % key)
            continue
        to_pipe.delete(key)
        to_pipe.restore(key, ttl=max(res_map[key][0], 0), value=res_map[key][1])
    to_pipe.execute()

    from_pipe = from_redis.pipeline(transaction=False)
    for key in keys:
        from_pipe.delete(key)
    from_pipe.execute()


def main():
    from_redis = redis.StrictRedis(host=FROM_REDIS_HOST_PORT_DB[0], port=FROM_REDIS_HOST_PORT_DB[1],
                                   db=FROM_REDIS_HOST_PORT_DB[2])
    to_redis = redis.StrictRedis(host=TO_REDIS_HOST_PORT_DB[0], port=TO_REDIS_HOST_PORT_DB[1],
                                 db=TO_REDIS_HOST_PORT_DB[2])

    cursor = 0
    start = time.time()
    count = 0
    while True:
        cursor, keys = from_redis.scan(cursor=cursor, count=EACH_SCAN_SIZE)
        migrate_keys(from_redis, to_redis, keys)
        if cursor == 0:
            logger.info('v, dumps keys complete')
            break
        count += len(keys)
        logger.info('v, dumps keys %d/%d/..., time: %s' % (len(keys), count, time.time() - start))
        time.sleep(0.001)


def test_one():
    from_redis = redis.StrictRedis(host=FROM_REDIS_HOST_PORT_DB[0], port=FROM_REDIS_HOST_PORT_DB[1],
                                   db=FROM_REDIS_HOST_PORT_DB[2])
    to_redis = redis.StrictRedis(host=TO_REDIS_HOST_PORT_DB[0], port=TO_REDIS_HOST_PORT_DB[1],
                                 db=TO_REDIS_HOST_PORT_DB[2])
    keys = ['u:881332:alive', 'u:881332:ua', 'u:881332:fu:lts', 'u:881332:fu:ots', 'u:881332:fa:lts', 'u:881332:fa:ots',
            'u:881332:cf:p', 'u:881332:f', 'follow-mutual:881332', 'following:881332', 'follower:881332']
    migrate_keys(from_redis, to_redis, keys)


if __name__ == '__main__':
    main()
    # test_one()