Re: [PATCH 10/22] Python: add utility function for retrieving port redirection

[Wainer dos Santos Moschetta <wainersm@redhat.com>]

Hi,

On 2/3/21 2:23 PM, Cleber Rosa wrote:
> Slightly different versions for the same utility code are currently
> present on different locations.  This unifies them all, giving
> preference to the version from virtiofs_submounts.py, because of the
> last tweaks added to it.
>
> While at it, this adds a "qemu.util" module to host the utility
> function and a test.
>
> Signed-off-by: Cleber Rosa <crosa@redhat.com>
> ---
>   python/qemu/utils.py                     | 35 ++++++++++++++++++++++++
>   tests/acceptance/info_usernet.py         | 29 ++++++++++++++++++++
>   tests/acceptance/linux_ssh_mips_malta.py | 16 +++++------
>   tests/acceptance/virtiofs_submounts.py   | 20 +++-----------
>   tests/vm/basevm.py                       |  7 ++---
>   5 files changed, 77 insertions(+), 30 deletions(-)
>   create mode 100644 python/qemu/utils.py
>   create mode 100644 tests/acceptance/info_usernet.py

I've a few suggestions:

- IMHO "utils" is too broad, people may start throwing random stuffs 
there. Maybe call it "net". I am sure there will be more net-related 
code to be clustered on that module in the future.

- Rename the method to "get_hostfwd_port()" because the parameter's name 
already implies it is expected an "info usernet" output.

- Drop the InfoUsernet Test. It is too simple, and the same 
functionality is tested indirectly by other tests.

>
> diff --git a/python/qemu/utils.py b/python/qemu/utils.py
> new file mode 100644
> index 0000000000..89a246ab30
> --- /dev/null
> +++ b/python/qemu/utils.py
> @@ -0,0 +1,35 @@
> +"""
> +QEMU utility library
> +
> +This offers miscellaneous utility functions, which may not be easily
> +distinguishable or numerous to be in their own module.
> +"""
> +
> +# Copyright (C) 2021 Red Hat Inc.
> +#
> +# Authors:
> +#  Cleber Rosa <crosa@redhat.com>
> +#
> +# This work is licensed under the terms of the GNU GPL, version 2.  See
> +# the COPYING file in the top-level directory.
> +#
> +
> +import re
> +from typing import Optional
> +
> +
> +def get_info_usernet_hostfwd_port(info_usernet_output: str) -> Optional[int]:
> +    """
> +    Returns the port given to the hostfwd parameter via info usernet
> +
> +    :param info_usernet_output: output generated by hmp command "info usernet"
> +    :param info_usernet_output: str
> +    :return: the port number allocated by the hostfwd option
> +    :rtype: int
> +    """
> +    for line in info_usernet_output.split('\r\n'):
> +        regex = r'TCP.HOST_FORWARD.*127\.0\.0\.1\s+(\d+)\s+10\.'
> +        match = re.search(regex, line)
> +        if match is not None:
> +            return int(match[1])
> +    return None
> diff --git a/tests/acceptance/info_usernet.py b/tests/acceptance/info_usernet.py
> new file mode 100644
> index 0000000000..9c1fd903a0
> --- /dev/null
> +++ b/tests/acceptance/info_usernet.py
> @@ -0,0 +1,29 @@
> +# Test for the hmp command "info usernet"
> +#
> +# Copyright (c) 2021 Red Hat, Inc.
> +#
> +# Author:
> +#  Cleber Rosa <crosa@redhat.com>
> +#
> +# This work is licensed under the terms of the GNU GPL, version 2 or
> +# later.  See the COPYING file in the top-level directory.
> +
> +from avocado_qemu import Test
> +
> +from qemu.utils import get_info_usernet_hostfwd_port
> +
> +
> +class InfoUsernet(Test):
> +
> +    def test_hostfwd(self):
> +        self.vm.add_args('-netdev', 'user,id=vnet,hostfwd=:127.0.0.1:0-:22')
> +        self.vm.launch()
> +        res = self.vm.command('human-monitor-command',
> +                              command_line='info usernet')
> +        port = get_info_usernet_hostfwd_port(res)
> +        self.assertIsNotNone(port,
> +                             ('"info usernet" output content does not seem to '
> +                              'contain the redirected port'))
> +        self.assertGreater(port, 0,
> +                           ('Found a redirected port that is not greater than'
> +                            ' zero'))
> diff --git a/tests/acceptance/linux_ssh_mips_malta.py b/tests/acceptance/linux_ssh_mips_malta.py
> index 25c5c5f741..275659c785 100644
> --- a/tests/acceptance/linux_ssh_mips_malta.py
> +++ b/tests/acceptance/linux_ssh_mips_malta.py
> @@ -18,6 +18,8 @@ from avocado.utils import process
>   from avocado.utils import archive
>   from avocado.utils import ssh
>   
> +from qemu.utils import get_info_usernet_hostfwd_port
> +
>   
>   class LinuxSSH(Test):
>   
> @@ -70,18 +72,14 @@ class LinuxSSH(Test):
>       def setUp(self):
>           super(LinuxSSH, self).setUp()
>   
> -    def get_portfwd(self):
> +    def ssh_connect(self, username, password):
> +        self.ssh_logger = logging.getLogger('ssh')
>           res = self.vm.command('human-monitor-command',
>                                 command_line='info usernet')
> -        line = res.split('\r\n')[2]
> -        port = re.split(r'.*TCP.HOST_FORWARD.*127\.0\.0\.1 (\d+)\s+10\..*',
> -                        line)[1]
> +        port = get_info_usernet_hostfwd_port(res)
> +        if not port:
> +            self.cancel("Failed to retrieve SSH port")

Here I think it should assert not none, otherwise there is a bug somewhere.

- Wainer

>           self.log.debug("sshd listening on port:" + port)
> -        return port
> -
> -    def ssh_connect(self, username, password):
> -        self.ssh_logger = logging.getLogger('ssh')
> -        port = self.get_portfwd()
>           self.ssh_session = ssh.Session(self.VM_IP, port=int(port),
>                                          user=username, password=password)
>           for i in range(10):
> diff --git a/tests/acceptance/virtiofs_submounts.py b/tests/acceptance/virtiofs_submounts.py
> index 0f9d7a5d9c..bf99164fcb 100644
> --- a/tests/acceptance/virtiofs_submounts.py
> +++ b/tests/acceptance/virtiofs_submounts.py
> @@ -10,6 +10,7 @@ from avocado_qemu import wait_for_console_pattern
>   from avocado.utils import ssh
>   
>   from qemu.accel import kvm_available
> +from qemu.utils import get_info_usernet_hostfwd_port
>   
>   from boot_linux import BootLinux
>   
> @@ -76,27 +77,14 @@ class VirtiofsSubmountsTest(BootLinux):
>       :avocado: tags=arch:x86_64
>       """
>   
> -    def get_portfwd(self):
> -        port = None
> -
> +    def ssh_connect(self, username, keyfile):
> +        self.ssh_logger = logging.getLogger('ssh')
>           res = self.vm.command('human-monitor-command',
>                                 command_line='info usernet')
> -        for line in res.split('\r\n'):
> -            match = \
> -                re.search(r'TCP.HOST_FORWARD.*127\.0\.0\.1\s+(\d+)\s+10\.',
> -                          line)
> -            if match is not None:
> -                port = int(match[1])
> -                break
> -
> +        port = get_info_usernet_hostfwd_port(res)
>           self.assertIsNotNone(port)
>           self.assertGreater(port, 0)
>           self.log.debug('sshd listening on port: %d', port)
> -        return port
> -
> -    def ssh_connect(self, username, keyfile):
> -        self.ssh_logger = logging.getLogger('ssh')
> -        port = self.get_portfwd()
>           self.ssh_session = ssh.Session('127.0.0.1', port=port,
>                                          user=username, key=keyfile)
>           for i in range(10):
> diff --git a/tests/vm/basevm.py b/tests/vm/basevm.py
> index 00f1d5ca8d..75ce07df36 100644
> --- a/tests/vm/basevm.py
> +++ b/tests/vm/basevm.py
> @@ -21,6 +21,7 @@ import datetime
>   sys.path.append(os.path.join(os.path.dirname(__file__), '..', '..', 'python'))
>   from qemu.accel import kvm_available
>   from qemu.machine import QEMUMachine
> +from qemu.utils import get_info_usernet_hostfwd_port
>   import subprocess
>   import hashlib
>   import argparse
> @@ -306,11 +307,7 @@ class BaseVM(object):
>           self.console_init()
>           usernet_info = guest.qmp("human-monitor-command",
>                                    command_line="info usernet")
> -        self.ssh_port = None
> -        for l in usernet_info["return"].splitlines():
> -            fields = l.split()
> -            if "TCP[HOST_FORWARD]" in fields and "22" in fields:
> -                self.ssh_port = l.split()[3]
> +        self.ssh_port = get_info_usernet_hostfwd_port(usernet_info)
>           if not self.ssh_port:
>               raise Exception("Cannot find ssh port from 'info usernet':\n%s" % \
>                               usernet_info)