Re: [PATCH v3] iotests: Test NBD client reconnection

[Vladimir Sementsov-Ogievskiy]

01.11.2019 19:54, Andrey Shinkevich wrote:
> The test for an NBD client. The NBD server is disconnected after the
> client write request. The NBD client should reconnect and complete
> the write operation.
> 
> Suggested-by: Denis V. Lunev <address@hidden>
> Suggested-by: Vladimir Sementsov-Ogievskiy <address@hidden>
> Signed-off-by: Andrey Shinkevich <address@hidden>
> ---
>   tests/qemu-iotests/277                   | 102 
> +++++++++++++++++++++++++++++++
>   tests/qemu-iotests/277.out               |   6 ++
>   tests/qemu-iotests/group                 |   1 +
>   tests/qemu-iotests/iotests.py            |   5 ++
>   tests/qemu-iotests/nbd-fault-injector.py |   3 +-
>   5 files changed, 116 insertions(+), 1 deletion(-)
>   create mode 100755 tests/qemu-iotests/277
>   create mode 100644 tests/qemu-iotests/277.out
> 
> diff --git a/tests/qemu-iotests/277 b/tests/qemu-iotests/277
> new file mode 100755
> index 0000000..e4e6730
> --- /dev/null
> +++ b/tests/qemu-iotests/277
> @@ -0,0 +1,102 @@
> +#!/usr/bin/env python
> +#
> +# Test NBD client reconnection
> +#
> +# Copyright (c) 2019 Virtuozzo International GmbH
> +#
> +# This program is free software; you can redistribute it and/or modify
> +# it under the terms of the GNU General Public License as published by
> +# the Free Software Foundation; either version 2 of the License, or
> +# (at your option) any later version.
> +#
> +# This program is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +# GNU General Public License for more details.
> +#
> +# You should have received a copy of the GNU General Public License
> +# along with this program.  If not, see <http://www.gnu.org/licenses/>.
> +#
> +
> +import os
> +import subprocess
> +import iotests
> +from iotests import file_path, log
> +
> +
> +def make_conf_file(event):
> +    """
> +    Create configuration file for the nbd-fault-injector.py
> +
> +    :param event: which event the server should close a connection on
> +    """
> +    if os.path.exists(conf_file):
> +        os.remove(conf_file)

a bit strange for my eyes to see global variable not defined higher in the file 
than used..

> +
> +    with open(conf_file, "w+") as conff:
> +        conff.write("[inject-error]\nevent={}\nwhen=after".format(event))

better open with "w" and don't need to remove file before it.

> +
> +
> +def start_server_NBD(event):
> +    make_conf_file(event)
> +
> +    srv = subprocess.Popen(["nbd-fault-injector.py", "--classic-negotiation",
> +                           nbd_sock, conf_file], stdout=subprocess.PIPE,
> +                           stderr=subprocess.STDOUT, universal_newlines=True)
> +    line = srv.stdout.readline()
> +    if "Listening on " in line:
> +        log('NBD server: started')
> +    else:
> +        log('NBD server: ' + line.rstrip())
> +
> +    return srv
> +
> +
> +def start_client_NBD():
> +    log('NBD client: QEMU-IO write')
> +    args = iotests.qemu_io_args_no_fmt + \
> +        ['-c', 'write -P 0x7 0 3M', '--image-opts',
> +         'driver=nbd,server.type=unix,server.path={},'
> +         'reconnect-delay=7'.format(nbd_sock)]
> +    clt = subprocess.Popen(args, stdout=subprocess.PIPE,
> +                           stderr=subprocess.STDOUT,
> +                           universal_newlines=True)
> +    return clt

Could you reuse QemuIoInteractive as a client?

> +
> +
> +def check_proc_NBD(proc, connector):
> +    try:
> +        exitcode = proc.wait(timeout=10)
> +
> +        if exitcode < 0:
> +            log('NBD {}: EXIT SIGNAL {}\n'.format(connector, -exitcode))
> +            log(proc.communicate()[0])
> +        else:
> +            line = proc.stdout.readline()


could we use proc.communicate() for both cases, what is the difference?

> +            log('NBD {}: {}'.format(connector, line.rstrip()))
> +
> +    except subprocess.TimeoutExpired:
> +        proc.kill()
> +        log('NBD {}: ERROR timeout expired'.format(connector))
> +    finally:
> +        if connector == 'server':
> +            os.remove(nbd_sock)
> +            os.remove(conf_file)
> +
> +
> +conf_file = os.path.join(iotests.test_dir, "nbd-fault-injector.conf")

use file_path here too.

> +nbd_sock = file_path('nbd-sock')
> +nbd_uri = 'nbd+unix:///?socket=' + nbd_sock

unused variable

> +if os.path.exists(nbd_sock):
> +    os.remove(nbd_sock)

I don't think we need this

> +
> +srv = start_server_NBD('data')
> +clt = start_client_NBD()
> +# The server should close the connection after a client write request
> +check_proc_NBD(srv, 'server')
> +# Start the NBD server again
> +srv = start_server_NBD('reply')
> +# The client should reconnect and complete the write operation
> +check_proc_NBD(clt, 'client')
> +# Make it sure that server terminated
> +check_proc_NBD(srv, 'server')
> diff --git a/tests/qemu-iotests/277.out b/tests/qemu-iotests/277.out
> new file mode 100644
> index 0000000..45404b3
> --- /dev/null
> +++ b/tests/qemu-iotests/277.out
> @@ -0,0 +1,6 @@
> +NBD server: started
> +NBD client: QEMU-IO write
> +NBD server: Closing connection on rule match inject-error
> +NBD server: started
> +NBD client: wrote 3145728/3145728 bytes at offset 0
> +NBD server: Closing connection on rule match inject-error
> diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
> index af322af..22ef1b8 100644
> --- a/tests/qemu-iotests/group
> +++ b/tests/qemu-iotests/group
> @@ -282,3 +282,4 @@
>   267 rw auto quick snapshot
>   268 rw auto quick
>   270 rw backing quick
> +277 rw
> diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
> index 709def4..0d16303 100644
> --- a/tests/qemu-iotests/iotests.py
> +++ b/tests/qemu-iotests/iotests.py
> @@ -47,6 +47,11 @@ qemu_io_args = [os.environ.get('QEMU_IO_PROG', 'qemu-io')]
>   if os.environ.get('QEMU_IO_OPTIONS'):
>       qemu_io_args += os.environ['QEMU_IO_OPTIONS'].strip().split(' ')
>   
> +qemu_io_args_no_fmt = [os.environ.get('QEMU_IO_PROG', 'qemu-io')]
> +if os.environ.get('QEMU_IO_OPTIONS_NO_FMT'):
> +    qemu_io_args_no_fmt += \
> +        os.environ['QEMU_IO_OPTIONS_NO_FMT'].strip().split(' ')
> +
>   qemu_nbd_args = [os.environ.get('QEMU_NBD_PROG', 'qemu-nbd')]
>   if os.environ.get('QEMU_NBD_OPTIONS'):
>       qemu_nbd_args += os.environ['QEMU_NBD_OPTIONS'].strip().split(' ')
> diff --git a/tests/qemu-iotests/nbd-fault-injector.py 
> b/tests/qemu-iotests/nbd-fault-injector.py
> index 6b2d659..7e2dab6 100755
> --- a/tests/qemu-iotests/nbd-fault-injector.py
> +++ b/tests/qemu-iotests/nbd-fault-injector.py
> @@ -115,7 +115,8 @@ class FaultInjectionSocket(object):
>               if rule.match(event, io):
>                   if rule.when == 0 or bufsize is None:
>                       print('Closing connection on rule match %s' % rule.name)
> -                    self.sock.flush()
> +                    self.sock.close()
> +                    sys.stdout.flush()

Why do you need this? It should be mentioned in commit message I think.

>                       sys.exit(0)
>                   if rule.when != -1:
>                       return rule.when
> 


-- 
Best regards,
Vladimir