Copy keys & values from one Redis instance to another

redis-dump-restore

#!/usr/bin/env python3

import sys
import asyncio
import argparse

from redis import StrictRedis


class Async:

    def __init__(self, wrapped):
        self._wrapped = wrapped

    def __getattr__(self, attr):
        value = getattr(self._wrapped, attr)
        if callable(value):
            async def func(*args, **kwargs):
                return value(*args, **kwargs)
            return func
        else:
            return value


async def main():
    (source, destination) = parse_args()

    async def dump_restore(key):
        ttl = max(0, source.ttl(key))
        value = source.dump(key)
        destination.restore(key, ttl=ttl, value=value, replace=True)

    counter = 0
    size = source.dbsize()
    save_cursor_position = "\033[s"
    sys.stderr.write(save_cursor_position)
    scan_task = asyncio.create_task(Async(source).scan(cursor=0))
    while True:
        (cursor, keys) = await scan_task
        scan_task = asyncio.create_task(Async(source).scan(cursor=cursor))
        for task in [asyncio.create_task(dump_restore(key)) for key in keys]:
            await task
            counter += 1
            write_progress(size, counter)
        if cursor == 0: break


def parse_args():
    parser = argparse.ArgumentParser()
    parser.add_argument("source", type=StrictRedis.from_url)
    parser.add_argument("destination", type=StrictRedis.from_url)
    parsed = parser.parse_args()
    return (parsed.source, parsed.destination)


def write_progress(size, counter):
    restore_cursor_position = "\033[u"
    percent = (100.0 * counter) / size
    sys.stderr.write(
        f"{restore_cursor_position}"
        f"{counter} / {size} "
        f"({percent:.2f}%) "
        "\n"
    )
    sys.stderr.flush()


if __name__ == "__main__": asyncio.run(main(), debug=True)

setup.py

from setuptools import setup

setup(
    name='Redis Dump Restore',
    version='0.1.0',
    scripts=['redis-dump-restore'],
    install_requires=['redis>=3.3'],
    python_requires='>=3.7',
)