Running redis-server using knc and a proxy

redis_knc_proxy.py

"""
knc proxy for redis

Created by iyerrah on 29-July-2017
"""
from __future__ import print_function
import os
import multiprocessing
import socket


BUFFER_SIZE = 32 * 1024

def main():
    """
    Driver of the program
    """
    if os.path.exists('/tmp/redis.knc.sock'):
        os.unlink('/tmp/redis.knc.sock')

    knc = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
    knc.bind('/tmp/redis.knc.sock')
    knc.listen(1)

    redis = socket.socket(socket.AF_UNIX)
    redis.connect('/tmp/redis.sock')

    while True:
        conn, addr = knc.accept()
        print('Accepted connection from', addr)
        handler = multiprocessing.Process(target=handle_client, args=(conn, redis))
        # handler.daemon = True
        handler.start()


def handle_client(client, redis):
    """
    Handle the connection from a client and redirect it to redis

    :param client: the client connection object
    :param redis: socket connection to redis
    """
    while True: # Read till connection is alive
        data = read_till_no_data(client)
        if not data:
            break
        print('Received from client', data)
        # Strip knc's END\n
        try:
            idx = data.index('END\n')
            data = data[idx:]
        except ValueError:
            pass
        redis.sendall(data)
        data = read_till_no_data(redis)
        if not data:
            break
        print('Received from redis', data)
        client.sendall(data)
    client.close()


def read_till_no_data(conn, timeout=0.01):
    """
    Read from the socket connection till there is a timeout

    :param conn: socket connection to be read from
    :param timeout: time in seconds to wait before a timeout. Default is `0.01`
    :return: the data read from the socket
    """
    conn.settimeout(timeout)
    data = None
    while True: # Read till no more data
        try:
            new_data = conn.recv(BUFFER_SIZE)
            if data:
                data += new_data
            else:
                data = new_data
        except socket.timeout, e:
            if not data:
                continue
            break
        except socket.error, e:
            print(e)
            break
    return data


if __name__ == '__main__':
    main()

run.sh

#!/bin/sh

redis-server \
  --unixsocket /tmp/redis.sock \
  --unixsocketperm 700 \
  > redis_server.log 2>&1 &
# Wait for the server to start
sleep 1
# Start the proxy
python redis_knc_proxy.py > redis_knc_proxy.log 2>&1 &
# Wait for the proxy to start up
sleep 1
exec redis-cli -s /tmp/redis.knc.sock