nose / nose / plugins /

This plugin captures logging statements issued during test
execution, appending any output captured to the error or failure
output, should the test fail or raise an error. It is enabled by
default but may be disabled with the options --nologcapture.

To remove any other installed logging handlers, use the
--logging-clear-handlers option.

When an error or failure occurs, captures log messages are attached to
the running test in the test.capturedLogging attribute, and added to
the error failure output.

You can filter logging statements captured with the --logging-filter option. 
If set, it specifies which logger(s) will be captured; loggers that do not match
will be passed. Example: specifying --logging-filter=sqlalchemy,myapp 
will ensure that only statements logged via sqlalchemy.engine or myapp
or logger will be logged.

import logging
from logging.handlers import BufferingHandler

from nose.plugins.base import Plugin
from nose.util import ln, safe_str

    from cStringIO import StringIO
except ImportError:
    from StringIO import StringIO

log = logging.getLogger(__name__)

class MyMemoryHandler(BufferingHandler):
    def __init__(self, capacity, logformat, logdatefmt, filters):
        BufferingHandler.__init__(self, capacity)
        fmt = logging.Formatter(logformat, logdatefmt)
        self.filters = filters
    def flush(self):
        pass # do nothing
    def truncate(self):
        self.buffer = []
    def filter(self, record):
        """Our custom record filtering logic.

        Built-in filtering logic (via logging.Filter) is too limiting.
        if not self.filters:
            return True
        matched = False
        rname = # shortcut
        for name in self.filters:
            if rname == name or rname.startswith(name+'.'):
                matched = True
        return matched

class LogCapture(Plugin):
    Log capture plugin. Enabled by default. Disable with --nologcapture.
    This plugin captures logging statement issued during test execution,
    appending any output captured to the error or failure output,
    should the test fail or raise an error.    
    enabled = True
    env_opt = 'NOSE_NOLOGCAPTURE'
    name = 'logcapture'
    score = 500
    logformat = '%(name)s: %(levelname)s: %(message)s'
    logdatefmt = None
    clear = False
    filters = []
    def options(self, parser, env):
        """Register commandline options.
            "--nologcapture", action="store_false",
            default=not env.get(self.env_opt), dest="logcapture",
            help="Disable logging capture plugin. "
                 "Logging configurtion will be left intact."
                 " [NOSE_NOLOGCAPTURE]")
            "--logging-format", action="store", dest="logcapture_format",
            default=env.get('NOSE_LOGFORMAT') or self.logformat,
            help="Specify custom format to print statements. "
                 "Uses the same format as used by standard logging handlers."
                 " [NOSE_LOGFORMAT]")
            "--logging-datefmt", action="store", dest="logcapture_datefmt",
            default=env.get('NOSE_LOGDATEFMT') or self.logdatefmt,
            help="Specify custom date/time format to print statements. "
                 "Uses the same format as used by standard logging handlers."
                 " [NOSE_LOGDATEFMT]")
            "--logging-filter", action="store", dest="logcapture_filters",
            help="Specify which statements to filter in/out. "
                 "By default everything is captured. If the output is too"
                 " verbose,\nuse this option to filter out needless output\n"
                 "Example: filter=foo will capture statements issued ONLY to\n"
                 " foo or foo.what.ever.sub but not foobar or other logger.\n"
                 "Specify multiple loggers with comma: filter=foo,bar,baz."
                 " [NOSE_LOGFILTER]\n")
            "--logging-clear-handlers", action="store_true",
            default=False, dest="logcapture_clear",
            help="Clear all other logging handlers")

    def configure(self, options, conf):
        """Configure plugin.
        self.conf = conf
        # Disable if explicitly disabled, or if logging is
        # configured via logging config file
        if not options.logcapture or conf.loggingConfig:
            self.enabled = False        
        self.logformat = options.logcapture_format
        self.logdatefmt = options.logcapture_datefmt
        self.clear = options.logcapture_clear
        if options.logcapture_filters:
            self.filters = options.logcapture_filters.split(',')
    def setupLoghandler(self):
        # setup our handler with root logger
        root_logger = logging.getLogger()
        if self.clear:
            for logger in logging.Logger.manager.loggerDict.values():
                if hasattr(logger, "handlers"):
                    for handler in logger.handlers:
        # make sure there isn't one already
        # you can't simply use "if self.handler not in root_logger.handlers"
        # since at least in unit tests this doesn't work --
        # LogCapture() is instantiated for each test case while root_logger
        # is module global
        # so we always add new MyMemoryHandler instance
        for handler in root_logger.handlers[:]:
            if isinstance(handler, MyMemoryHandler):
        # to make sure everything gets captured

    def begin(self):
        """Set up logging handler before test run begins.

    def start(self):
        self.handler = MyMemoryHandler(1000, self.logformat, self.logdatefmt,

    def end(self):

    def beforeTest(self, test):
        """Clear buffers and handlers before test.

    def afterTest(self, test):
        """Clear buffers after test.

    def formatFailure(self, test, err):
        """Add captured log messages to failure output.
        return self.formatError(test, err)

    def formatError(self, test, err):
        """Add captured log messages to error output.
        # logic flow copied from Capture.formatError
        test.capturedLogging = records = self.formatLogRecords()
        if not records:
            return err 
        ec, ev, tb = err
        return (ec, self.addCaptureToErr(ev, records), tb)

    def formatLogRecords(self):
        format = self.handler.format
        return [safe_str(format(r)) for r in self.handler.buffer]

    def addCaptureToErr(self, ev, records):
        return '\n'.join([safe_str(ev), ln('>> begin captured logging <<')] + \
                          records + \
                          [ln('>> end captured logging <<')])