Source code for pyscaffold.log
# -*- coding: utf-8 -*-
"""
Custom logging infrastructure to provide execution information for the user.
"""
from collections import defaultdict
from contextlib import contextmanager
from logging import INFO, Formatter, LoggerAdapter, StreamHandler, getLogger
from os.path import realpath, relpath
from os.path import sep as pathsep
from . import termui
DEFAULT_LOGGER = __name__
def _are_equal_paths(path1, path2):
return realpath(path1) == realpath(path2)
def _is_current_path(path):
return _are_equal_paths(path, '.')
[docs]def configure_logger(opts):
"""Configure the default logger
Args:
opts (dict): command line parameters
"""
if 'log_level' in opts:
logger.level = opts['log_level']
# if terminal supports, use colors
stream = getattr(logger.handler, 'stream', None)
if termui.supports_color(stream):
logger.formatter = ColoredReportFormatter()
logger.handler.setFormatter(logger.formatter)
[docs]class ReportFormatter(Formatter):
"""Formatter that understands custom fields in the log record."""
ACTIVITY_MAXLEN = 12
SPACING = ' '
CONTEXT_PREFIX = 'from'
TARGET_PREFIX = 'to'
[docs] def format(self, record):
"""Compose message when a record with report information is given."""
if hasattr(record, 'activity'):
return self.format_report(record)
return self.format_default(record)
[docs] def create_padding(self, activity):
"""Create the appropriate padding in order to align activities."""
actual = len(activity)
count = max(self.ACTIVITY_MAXLEN - actual, 0)
return ' ' * count
[docs] def format_path(self, path):
"""Simplify paths to avoid wasting space in terminal."""
from .utils import is_pathname_valid # late import due to cycles
if is_pathname_valid(path) and pathsep in path:
# Heuristic to determine if subject is a file path
# that needs to be made short
abbrev = relpath(path)
if len(abbrev) < len(path):
# Ignore if not shorter
path = abbrev
return path
# Subclasses may need the activity name to choose correct format,
# so the following 3 methods accept a second parameter
# (even if they not use it)
[docs] def format_subject(self, subject, _activity=None):
"""Format the subject of the activity."""
return self.format_path(subject)
[docs] def format_target(self, target, _activity=None):
"""Format extra information about the activity target."""
if target and not _is_current_path(target):
return "{} '{}'".format(self.TARGET_PREFIX,
self.format_path(target))
return ''
[docs] def format_context(self, context, _activity=None):
"""Format extra information about the activity context."""
if context and not _is_current_path(context):
return "{} '{}'".format(self.CONTEXT_PREFIX,
self.format_path(context))
return ''
[docs] def format_default(self, record):
"""Format default log messages."""
record.msg = self.SPACING * max(record.nesting, 0) + record.msg
return super(ReportFormatter, self).format(record)
[docs] def format_report(self, record):
"""Compose message when a custom record is given."""
activity = record.activity
record.msg = (
self.create_padding(activity) +
self.format_activity(activity) +
self.SPACING * max(record.nesting + 1, 0) +
' '.join([
text for text in [
self.format_subject(record.subject, activity),
self.format_target(record.target, activity),
self.format_context(record.context, activity)
] if text # Filter empty strings
])
)
return super(ReportFormatter, self).format(record)
[docs]class ColoredReportFormatter(ReportFormatter):
"""Format logs with ANSI colors."""
ACTIVITY_STYLES = defaultdict(
lambda: ('blue', 'bold'),
create=('green', 'bold'),
move=('green', 'bold'),
remove=('red', 'bold'),
delete=('red', 'bold'),
skip=('yellow', 'bold'),
run=('magenta', 'bold'),
invoke=('bold',)
)
SUBJECT_STYLES = defaultdict(
tuple,
invoke=('blue',)
)
LOG_STYLES = defaultdict(
tuple,
debug=('green',),
info=('blue',),
warning=('yellow',),
error=('red',),
critical=('red', 'bold')
)
CONTEXT_PREFIX = termui.decorate(
ReportFormatter.CONTEXT_PREFIX, 'magenta', 'bold')
TARGET_PREFIX = termui.decorate(
ReportFormatter.TARGET_PREFIX, 'magenta', 'bold')
[docs] def format_activity(self, activity):
return termui.decorate(activity, *self.ACTIVITY_STYLES[activity])
[docs] def format_subject(self, subject, activity=None):
parent = super(ColoredReportFormatter, self)
subject = parent.format_subject(subject, activity)
return termui.decorate(subject, *self.SUBJECT_STYLES[activity])
[docs] def format_default(self, record):
record.msg = termui.decorate(
record.msg, *self.LOG_STYLES[record.levelname.lower()])
return super(ColoredReportFormatter, self).format_default(record)
[docs]class ReportLogger(LoggerAdapter):
"""Suitable wrapper for PyScaffold CLI interactive execution reports.
Args:
logger (logging.Logger): custom logger to be used. Optional: the
default logger will be used.
handlers (logging.Handler): custom logging handler to be used.
Optional: a :class:`logging.StreamHandler` is used by default.
formatter (logging.Formatter): custom formatter to be used.
Optional: by default a :class:`~.ReportFormatter` is created and
used.
extra (dict): extra attributes to be merged into the log record.
Options, empty by default.
Attributes:
wrapped (logging.Logger): underlying logger object.
handler (logging.Handler): stream handler configured for
providing user feedback in PyScaffold CLI.
formatter (logging.Formatter): formatter configured in the
default handler.
nesting (int): current nesting level of the report.
"""
def __init__(self, logger=None, handler=None, formatter=None, extra=None):
self.nesting = 0
self.wrapped = logger or getLogger(DEFAULT_LOGGER)
self.extra = extra or {}
self.handler = handler or StreamHandler()
self.formatter = formatter or ReportFormatter()
self.handler.setFormatter(self.formatter)
self.wrapped.addHandler(self.handler)
super(ReportLogger, self).__init__(self.wrapped, self.extra)
@property
def level(self):
"""Effective level of the logger"""
return self.wrapped.getEffectiveLevel()
@level.setter
def level(self, value):
"""Set the logger level"""
self.wrapped.setLevel(value)
[docs] def process(self, msg, kwargs):
"""Method overridden to augment LogRecord with the `nesting` attribute.
"""
(msg, kwargs) = super(ReportLogger, self).process(msg, kwargs)
extra = kwargs.get('extra', {})
extra['nesting'] = self.nesting
kwargs['extra'] = extra
return msg, kwargs
[docs] def report(self, activity, subject,
context=None, target=None, nesting=None, level=INFO):
"""Log that an activity has occurred during scaffold.
Args:
activity (str): usually a verb or command, e.g. ``create``,
``invoke``, ``run``, ``chdir``...
subject (str): usually a path in the file system or an action
identifier.
context (str): path where the activity take place.
target (str): path affected by the activity
nesting (int): optional nesting level. By default it is calculated
from the activity name.
level (int): log level. Defaults to :obj:`logging.INFO`.
See :mod:`logging` for more information.
Notes:
This method creates a custom log record, with additional fields:
**activity**, **subject**, **context**, **target** and **nesting**,
but an empty **msg** field. The :class:`ReportFormatter`
creates the log message from the other fields.
Often **target** and **context** complement the logs when
**subject** does not hold all the necessary information. For
example::
logger.report('copy', 'my/file', target='my/awesome/path')
logger.report('run', 'command', context='current/working/dir')
"""
return self.wrapped.log(level, '', extra={
'activity': activity,
'subject': subject,
'context': context,
'target': target,
'nesting': nesting or self.nesting
})
[docs] @contextmanager
def indent(self, count=1):
"""Temporarily adjust padding while executing a context.
Example:
.. code-block:: python
from pyscaffold.log import logger
logger.report('invoke', 'custom_action')
with logger.indent():
logger.report('create', 'some/file/path')
# Expected logs:
# --------------------------------------
# invoke custom_action
# create some/file/path
# --------------------------------------
# Note how the spacing between activity and subject in the
# second entry is greater than the equivalent in the first one.
Note:
This method is not thread-safe and should be used with care.
"""
prev = self.nesting
self.nesting += count
try:
yield
finally:
self.nesting = prev
[docs] def copy(self):
"""Produce a copy of the wrapped logger.
Sometimes, it is better to make a copy of th report logger to keep
indentation consistent.
"""
clone = self.__class__(self.wrapped, self.handler,
self.formatter, self.extra)
clone.nesting = self.nesting
return clone
logger = ReportLogger()
"""Default logger configured for PyScaffold."""