import paramiko
import sys


# connect to remote server
def connect_to_server(server_name, user_name):
    client = paramiko.SSHClient()
    client.set_missing_host_key_policy(paramiko.AutoAddPolicy)
    client.load_system_host_keys()
    client.connect(server_name, username=user_name, password=None)
    return client


# transfer file from remote host to local machine.
def copy_remote_file(client, remote_file, local_file):
        sftp = client.open_sftp()
        sftp.get(remote_file, local_file)


# run command on remote machine.
def run_remote_command(client, cmd):
    stdin, stdout, stderr = client.exec_command(cmd)
    return stdin, stdout, stderr


if __name__ == '__main__':

    server = sys.argv[1]
    user = sys.argv[2]
    command = sys.argv[3]
    remotefile = sys.argv[4]
    localfile = sys.argv[5]
    conn = connect_to_server(server, user)
    std_in, std_out, std_err = run_remote_command(conn, command)
    for line in std_err:
        print(' --> ' + line)

    print('copying remote file: %s\n' % remotefile)
    copy_remote_file(conn, remotefile, localfile)

    conn.close()