[Piglit] [Patch v5 1/4] framework/dmesg: Adds a new module for dmesg

Dylan Baker baker.dylan.c at gmail.com
Tue Feb 4 10:12:14 PST 2014


On Tuesday, February 04, 2014 12:43:42 PM Ilia Mirkin wrote:
> On Tue, Feb 4, 2014 at 12:35 PM, Dylan Baker <baker.dylan.c at gmail.com> 
wrote:
> > This modules implements two classes and a helper function. The two
> > classes are both dmesg wrapper classes, one, PosixDmesg is used on posix
> > systems when requested to actually do checks on dmesg. The second class,
> > DummyDmesg, is used to reduce code complexity by providing dummy
> > versions of the methods in PosixDmesg. This means that we don't need
> > separate code paths for Posix systems wanting to check dmesg, Posix
> > systems not wanting to check dmesg, and non-posix systems which lack
> > dmesg.
> > 
> > Beyond reducing complexity this module also gives better isolation,
> > dmesg is only used in Test.execute(), no where else. Additional classes
> > don't need to worry about dmesg that way, it's just available.
> > 
> > v2: - Remove unnecessary assert from PosixDmesg.update_result()
> > 
> >     - simplify replace helper in PoixDmesg.update_result()
> >     - replace try/except with if check
> >     - Change PosixDmesg.update_dmesg() to work even if dmesg 'wraps'
> > 
> > v3: - Try/Except assignment of PosixDmesg._last_message in update_dmesg()
> > 
> >     - Set the dmesg levels the same as the previous implementation
> >     - Change PosixDmesg into LinuxDmesg and enforce that dmesg has
> >     
> >       timestamps
> > 
> > v4: - Add check in LinuxDmesg.__init__ to ensure there is something in
> > 
> >       dmesg before doing the timestamp check. This should make problems
> >       clearer
> >     
> >     - Refactor some code in LinuxDmesg.update_result()
> > 
> > v5: - Replace exception with warning.
> > 
> >     - add break to loop in dmesg.update_dmesg
> > 
> > Signed-off-by: Dylan Baker <baker.dylan.c at gmail.com>
> > ---
> > 
> >  framework/dmesg.py | 175
> >  +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed,
> >  175 insertions(+)
> >  create mode 100644 framework/dmesg.py
> > 
> > diff --git a/framework/dmesg.py b/framework/dmesg.py
> > new file mode 100644
> > index 0000000..feb05ad
> > --- /dev/null
> > +++ b/framework/dmesg.py
> > @@ -0,0 +1,175 @@
> > +# Copyright (c) 2013-2014 Intel Corporation
> > +#
> > +# Permission is hereby granted, free of charge, to any person obtaining a
> > +# copy of this software and associated documentation files (the
> > "Software"), +# to deal in the Software without restriction, including
> > without limitation +# the rights to use, copy, modify, merge, publish,
> > distribute, sublicense, +# and/or sell copies of the Software, and to
> > permit persons to whom the +# Software is furnished to do so, subject to
> > the following conditions: +#
> > +# The above copyright notice and this permission notice (including the
> > next +# paragraph) shall be included in all copies or substantial
> > portions of the +# Software.
> > +#
> > +# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
> > OR +# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
> > MERCHANTABILITY, +# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
> >  IN NO EVENT SHALL +# THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
> > CLAIM, DAMAGES OR OTHER +# LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
> > TORT OR OTHERWISE, ARISING +# FROM, OUT OF OR IN CONNECTION WITH THE
> > SOFTWARE OR THE USE OR OTHER DEALINGS +# IN THE SOFTWARE.
> > +
> > +""" Module implementing classes for reading posix dmesg
> > +
> > +Currently this module only has the default DummyDmesg, and a LinuxDmesg.
> > +The method used on Linux requires that timetamps are enabled, and no
> > other
> > +posix system has timestamps.
> > +
> > +On OSX and *BSD one would likely want to implement a system that reads
> > the
> > +sysloger, since timestamps can be added by the sysloger, and are not
> > inserted +by dmesg.
> > +
> > +"""
> > +
> > +import re
> > +import sys
> > +import subprocess
> > +import warnings
> > +
> > +__all__ = ['LinuxDmesg', 'DummyDmesg', 'get_dmesg']
> > +
> > +
> > +class LinuxDmesg(object):
> > +    """ Read dmesg on posix systems
> > +
> > +    This reads the dmesg ring buffer, stores the contents of the buffer,
> > and +    then compares it whenever called, returning the difference
> > between the +    calls. It requires timestamps to be enabled.
> > +
> > +    """
> > +    DMESG_COMMAND = ['dmesg', '--level',
> > 'emerg,alert,crit,err,warn,notice'] +
> > +    def __init__(self):
> > +        """ Create a dmesg instance """
> > +        self._last_message = None
> > +        self._new_messages = []
> > +
> > +        # Populate self.dmesg initially, otherwise the first test will
> > always +        # be full of dmesg crud.
> > +        self.update_dmesg()
> > +
> > +        if not self._last_message:
> > +            # We need to ensure that there is something in dmesg to check
> > +            # timestamps.
> > +            warnings.warn("Cannot check dmesg for timestamp support. If
> > you " +                          "do not have timestamps enabled in your
> > kernel you " +                          "get incomplete dmesg captures",
> > RuntimeWarning) +        elif not re.match(r'\[\s*\d+\.\d+\]',
> > self._last_message): +            # Do an initial check to ensure that
> > dmesg has timestamps, we need +            # timestamps to work
> > correctly. A proper linux dmesg timestamp +            # looks like this:
> > [    0.00000]
> > +            raise DmesgError(
> > +                "Your kernel does not seem to support timestamps, which "
> > +                "are required by the --dmesg option")
> 
> Consider also making this a warning.
> 
> Either way, Reviewed-by: Ilia Mirkin <imirkin at alum.mit.edu>
> 
> > +
> > +    def update_result(self, result):
> > +        """ Takes a TestResult object and updates it with dmesg statuses
> > +
> > +        If dmesg is enabled, and if dmesg has been updated, then replace
> > pass +        with dmesg-warn and warn and fail with dmesg-fail. If dmesg
> > has not +        been updated, it will return the original result passed
> > in. +
> > +        Arguments:
> > +        result -- A TestResult instance
> > +
> > +        """
> > +
> > +        def replace(res):
> > +            """ helper to replace statuses with the new dmesg status
> > +
> > +            Replaces pass with dmesg-warn, and warn and fail with
> > dmesg-fail, +            otherwise returns the input
> > +
> > +            """
> > +            return {"pass": "dmesg-warn",
> > +                    "warn": "dmesg-fail",
> > +                    "fail": "dmesg-fail"}.get(res, res)
> > +
> > +        # Get a new snapshot of dmesg
> > +        self.update_dmesg()
> > +
> > +        # if update_dmesg() found new entries replace the results of the
> > test +        # and subtests
> > +        if self._new_messages:
> > +            result['result'] = replace(result['result'])
> > +
> > +            # Replace any subtests
> > +            if 'subtest' in result:
> > +                for key, value in result['subtest'].iteritems():
> > +                    result['subtest'][key] = replace(value)
> > +
> > +            # Add the dmesg values to the result
> > +            result['dmesg'] = self._new_messages
> > +
> > +        return result
> > +
> > +    def update_dmesg(self):
> > +        """ Call dmesg using subprocess.check_output
> > +
> > +        Get the contents of dmesg, then calculate new messages, finally
> > set +        self.dmesg equal to the just read contents of dmesg.
> > +
> > +        """
> > +        dmesg =
> > subprocess.check_output(self.DMESG_COMMAND).strip().splitlines() +
> > +        # Find all new entries, do this by slicing the list of dmesg to
> > only +        # returns elements after the last element stored. If there
> > are not +        # matches a value error is raised, that means all of
> > dmesg is new +        l = 0
> > +        for index, item in enumerate(reversed(dmesg)):
> > +            if item == self._last_message:
> > +                l = len(dmesg) - index  # don't include the matched
> > element +                break
> > +        self._new_messages = dmesg[l:]
> > +
> > +        # Attempt to store the last element of dmesg, unless there was no
> > dmesg +        self._last_message = dmesg[-1] if dmesg else None
> > +
> > +
> > +class DummyDmesg(object):
> > +    """ An dummy class for dmesg on non unix-like systems
> > +
> > +    This implements a dummy version of the LinuxDmesg, and can be used
> > anytime +    it is not desirable to actually read dmesg, such as
> > non-posix systems, or +    when the contents of dmesg don't matter.
> > +
> > +    """
> > +    DMESG_COMMAND = []
> > +
> > +    def __init__(self):
> > +        pass
> > +
> > +    def update_dmesg(self):
> > +        """ Dummy version of update_dmesg """
> > +        pass
> > +
> > +    def update_result(self, result):
> > +        """ Dummy version of update_result """
> > +        return result
> > +
> > +
> > +class DmesgError(EnvironmentError):
> > +    pass
> > +
> > +
> > +def get_dmesg(not_dummy=True):
> > +    """ Return a Dmesg type instance
> > +
> > +    Normally this does a system check, and returns the type that proper
> > for +    your system. However, if Dummy is True then it will always
> > return a +    DummyDmesg instance.
> > +
> > +    """
> > +    if sys.platform.startswith('linux') and not_dummy:
> > +        return LinuxDmesg()
> > +    return DummyDmesg()
> > --
> > 1.8.5.3
> > 
> > _______________________________________________
> > Piglit mailing list
> > Piglit at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/piglit

Is that review for the series?
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