redis migrate

migrate-redis.py

#!/usr/bin/env python3
import argparse
import redis


def connect(conn_dict, tls):
    return redis.Redis(
        host=conn_dict['host'],
        password=conn_dict['password'],
        port=conn_dict['port'],
        db=conn_dict['db'],
        ssl=tls
    )


def conn_string_type(string):
    conn_format = '<host>:<port>:<db>:<password>'
    try:
        host, port, database, password = string.split(':')
        database = int(database)
    except ValueError:
        raise argparse.ArgumentTypeError(f'incorrect format, should be: {conn_format}')
    return {
        'host': host,
        'port': port,
        'db': database,
        'password': password
    }


def migrate_redis(source, destination):
    src = connect(source, None)
    dst = connect(destination, True) # elasticache has encryptionssrc
    for key in src.keys('*'):
        ttl = src.ttl(key)
        # handle TTL command returning -1 (no expire) or -2 (no key)
        if ttl < 0:
            ttl = 0
        print(f"Dumping key: {key.decode('UTF-8')}")
        value = src.dump(key)
        print(f"Restoring key: {key.decode('UTF-8')}")
        try:
            # the ttl key is stored in seconds
            # but restore expects milliseconds, so * 1000
            dst.restore(key, ttl * 1000, value, replace=True)
        except redis.exceptions.ResponseError:
            print(f"Failed to restore key: {key.decode('UTF-8')}")


def run():
    parser = argparse.ArgumentParser()
    parser.add_argument('source', type=conn_string_type)
    parser.add_argument('destination', type=conn_string_type)
    options = parser.parse_args()
    migrate_redis(options.source, options.destination)

if __name__ == '__main__':
    run()