Re: [PATCH 02/14] iotests.py: qemu_img*("create"): support IMGOPTS='compression_type=zstd' - Vladimir Sementsov-Ogievskiy

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
To: Max Reitz <mreitz@redhat.com>, qemu-block@nongnu.org
Cc: qemu-devel@nongnu.org, kwolf@redhat.com, den@openvz.org,
	jsnow@redhat.com
Subject: Re: [PATCH 02/14] iotests.py: qemu_img*("create"): support IMGOPTS='compression_type=zstd'
Date: Fri, 16 Jul 2021 13:34:59 +0300	[thread overview]
Message-ID: <34791223-deb6-36ec-1c97-9956da2395e2@virtuozzo.com> (raw)
In-Reply-To: <5e3574ea-2d7a-d159-3882-3e627841f368@redhat.com>

16.07.2021 13:07, Max Reitz wrote:
> On 05.07.21 11:15, Vladimir Sementsov-Ogievskiy wrote:
>> Adding support of IMGOPTS (like in bash tests) allows user to pass a
>> lot of different options. Still, some may require additional logic.
>>
>> Now we want compression_type option, so add some smart logic around it:
>> ignore compression_type=zstd in IMGOPTS, if test want qcow2 in
>> compatibility mode. As well, ignore compression_type for non-qcow2
>> formats.
>>
>> Note that we may instead add support only to qemu_img_create(), but
>> that works bad:
>>
>> 1. We'll have to update a lot of tests to use qemu_img_create instead
>>     of qemu_img('create'). (still, we may want do it anyway, but no
>>     reason to create a dependancy between task of supporting IMGOPTS and
>>     updating a lot of tests)
>>
>> 2. Some tests use qemu_img_pipe('create', ..) - even more work on
>>     updating
> 
> I feel compelled to again say that we had a series that did exactly that.  But of course, now that so much time has passed, overhauling it would require quite a bit of work.
> 
>> 3. Even if we update all tests to go through qemu_img_create, we'll
>>     need a way to avoid creating new tests using qemu_img*('create') -
>>     add assertions.. That doesn't seem good.
> 
> That almost sounds like you remember my series, because:
> 
> https://lists.nongnu.org/archive/html/qemu-block/2019-10/msg00135.html
> 
> ;)

:) No, I don't remember it.

> 
>> So, let's add support of IMGOPTS to most generic
>> qemu_img_pipe_and_status().
>>
>> Signed-off-by: Vladimir Sementsov-Ogievskiy<vsementsov@virtuozzo.com>
>> ---
>>   tests/qemu-iotests/iotests.py | 48 ++++++++++++++++++++++++++++++++++-
>>   1 file changed, 47 insertions(+), 1 deletion(-)
>>
>> diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
>> index 0d99dd841f..80f0cb4f42 100644
>> --- a/tests/qemu-iotests/iotests.py
>> +++ b/tests/qemu-iotests/iotests.py
>> @@ -16,6 +16,7 @@
>>   # along with this program.  If not, see<http://www.gnu.org/licenses/>.
>>   #
>> +import argparse
>>   import atexit
>>   import bz2
>>   from collections import OrderedDict
>> @@ -41,6 +42,19 @@
>>   from qemu.machine import qtest
>>   from qemu.qmp import QMPMessage
>> +
>> +def optstr2dict(opts: str) -> Dict[str, str]:
>> +    if not opts:
>> +        return {}
>> +
>> +    return {arr[0]: arr[1] for arr in
>> +            (opt.split('=', 1) for opt in opts.strip().split(','))}
>> +
>> +
>> +def dict2optstr(opts: Dict[str, str]) -> str:
>> +    return ','.join(f'{k}={v}' for k, v in opts.items())
>> +
>> +
>>   # Use this logger for logging messages directly from the iotests module
>>   logger = logging.getLogger('qemu.iotests')
>>   logger.addHandler(logging.NullHandler())
>> @@ -57,6 +71,8 @@
>>   if os.environ.get('QEMU_IMG_OPTIONS'):
>>       qemu_img_args += os.environ['QEMU_IMG_OPTIONS'].strip().split(' ')
>> +imgopts = optstr2dict(os.environ.get('IMGOPTS', ''))
>> +
>>   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(' ')
>> @@ -121,11 +137,41 @@ def qemu_tool_pipe_and_status(tool: str, args: Sequence[str],
>>                                  {-subp.returncode}: {cmd}\n')
>>           return (output, subp.returncode)
>> +def qemu_img_create_prepare_args(args: List[str]) -> List[str]:
>> +    if not args or args[0] != 'create':
>> +        return list(args)
>> +    args = args[1:]
>> +
>> +    p = argparse.ArgumentParser(allow_abbrev=False)
>> +    # -o option may be specified several times
>> +    p.add_argument('-o', action='append', default=[])
>> +    p.add_argument('-f')
>> +    parsed, remaining = p.parse_known_args(args)
>> +
>> +    opts = optstr2dict(','.join(parsed.o))
>> +
>> +    compat = 'compat' in opts and opts['compat'][0] == '0'
> 
> I suppose `opts['compat'][0] == '0'` is supposed to check for compat=0.10?
> 
> If so, then why not just check `opts['compat'] == '0.10'` to be clearer?  I don’t think we allow any other compat=0* values, and I have no reason to believe we ever will.
> 
> Also, I think compat=v2 is valid, too.  (And I think calling this variable “v2” would also make more sense than “compat”.)

Good for me, will do.

> 
>> +    for k, v in imgopts.items():
>> +        if k in opts:
>> +            continue
>> +        if k == 'compression_type' and (compat or parsed.f != 'qcow2'):
>> +            continue
>> +        opts[k] = v
> 
> Could also be done with something like
> 
> imgopts = os.environ.get('IMGOPTS')

imgopts is a string after it. So you don't need to join it?

> opts = optstr2dict(','.join(([imgopts] if imgopts else []) + parsed.o))

Build a string to be than parsed looks strange IMHO..

> 
> if parsed.f != 'qcow2' or (opts.get('compat') in ['v2', '0.10']):
>      opts.pop('compression_type', None)
> 
> (Never tested, of course)
> 
> Because optstr2dict() prioritizes later options over earlier ones. (Which is good, because that’s also qemu-img’s behavior.)
> 

Ok, I'll think about this all when prepare v2, and we'll see how it goes

> 
>> +
>> +    result = ['create']
>> +    if parsed.f is not None:
>> +        result += ['-f', parsed.f]
> 
> Can this even be None?  I hope none of our tests do this.

I'm afraid they do, as I first wanted to make a default to be imgfmt, but faced tests that rely on default being raw.. May be I'm wrong. Will check it.

> 
>> +    if opts:
>> +        result += ['-o', dict2optstr(opts)]
>> +    result += remaining
>> +
>> +    return result
>> +
>>   def qemu_img_pipe_and_status(*args: str) -> Tuple[str, int]:
>>       """
>>       Run qemu-img and return both its output and its exit code
>>       """
>> -    full_args = qemu_img_args + list(args)
>> +    full_args = qemu_img_args + qemu_img_create_prepare_args(list(args))
>>       return qemu_tool_pipe_and_status('qemu-img', full_args)
>>   def qemu_img(*args: str) -> int:
> 
> There’s also qemu_img_verbose() which I think should be amended the same way (even if it’s currently never used for 'create').
> 

Right, thanks. I think better is rewrite qemu_img_verbose to to call qemu_img_pipe_and_status.

Another thing to do is moving handling luks from qemu_img_create to qemu_img_create_prepare_args, so all these things be in one place.

-- 
Best regards,
Vladimir