bpo-34844: logging.Formatter enhancement - Ensure style and format string matches in logging.Formatter (GH-9703)
diff --git a/Lib/logging/__init__.py b/Lib/logging/__init__.py
index 7aeff45..58afcd2 100644
--- a/Lib/logging/__init__.py
+++ b/Lib/logging/__init__.py
@@ -23,9 +23,11 @@
To use, simply 'import logging' and log away!
"""
-import sys, os, time, io, traceback, warnings, weakref, collections.abc
+import sys, os, time, io, re, traceback, warnings, weakref, collections.abc
from string import Template
+from string import Formatter as StrFormatter
+
__all__ = ['BASIC_FORMAT', 'BufferingFormatter', 'CRITICAL', 'DEBUG', 'ERROR',
'FATAL', 'FileHandler', 'Filter', 'Formatter', 'Handler', 'INFO',
@@ -413,15 +415,20 @@
rv.__dict__.update(dict)
return rv
+
#---------------------------------------------------------------------------
# Formatter classes and functions
#---------------------------------------------------------------------------
+_str_formatter = StrFormatter()
+del StrFormatter
+
class PercentStyle(object):
default_format = '%(message)s'
asctime_format = '%(asctime)s'
asctime_search = '%(asctime)'
+ validation_pattern = re.compile(r'%\(\w+\)[#0+ -]*(\*|\d+)?(\.(\*|\d+))?[diouxefgcrsa%]', re.I)
def __init__(self, fmt):
self._fmt = fmt or self.default_format
@@ -429,17 +436,50 @@
def usesTime(self):
return self._fmt.find(self.asctime_search) >= 0
- def format(self, record):
+ def validate(self):
+ """Validate the input format, ensure it matches the correct style"""
+ if not self.validation_pattern.search(self._fmt):
+ raise ValueError("Invalid format '%s' for '%s' style" % (self._fmt, self.default_format[0]))
+
+ def _format(self, record):
return self._fmt % record.__dict__
+ def format(self, record):
+ try:
+ return self._format(record)
+ except KeyError as e:
+ raise ValueError('Formatting field not found in record: %s' % e)
+
+
class StrFormatStyle(PercentStyle):
default_format = '{message}'
asctime_format = '{asctime}'
asctime_search = '{asctime'
- def format(self, record):
+ fmt_spec = re.compile(r'^(.?[<>=^])?[+ -]?#?0?(\d+|{\w+})?[,_]?(\.(\d+|{\w+}))?[bcdefgnosx%]?$', re.I)
+ field_spec = re.compile(r'^(\d+|\w+)(\.\w+|\[[^]]+\])*$')
+
+ def _format(self, record):
return self._fmt.format(**record.__dict__)
+ def validate(self):
+ """Validate the input format, ensure it is the correct string formatting style"""
+ fields = set()
+ try:
+ for _, fieldname, spec, conversion in _str_formatter.parse(self._fmt):
+ if fieldname:
+ if not self.field_spec.match(fieldname):
+ raise ValueError('invalid field name/expression: %r' % fieldname)
+ fields.add(fieldname)
+ if conversion and conversion not in 'rsa':
+ raise ValueError('invalid conversion: %r' % conversion)
+ if spec and not self.fmt_spec.match(spec):
+ raise ValueError('bad specifier: %r' % spec)
+ except ValueError as e:
+ raise ValueError('invalid format: %s' % e)
+ if not fields:
+ raise ValueError('invalid format: no fields')
+
class StringTemplateStyle(PercentStyle):
default_format = '${message}'
@@ -454,9 +494,24 @@
fmt = self._fmt
return fmt.find('$asctime') >= 0 or fmt.find(self.asctime_format) >= 0
- def format(self, record):
+ def validate(self):
+ pattern = Template.pattern
+ fields = set()
+ for m in pattern.finditer(self._fmt):
+ d = m.groupdict()
+ if d['named']:
+ fields.add(d['named'])
+ elif d['braced']:
+ fields.add(d['braced'])
+ elif m.group(0) == '$':
+ raise ValueError('invalid format: bare \'$\' not allowed')
+ if not fields:
+ raise ValueError('invalid format: no fields')
+
+ def _format(self, record):
return self._tpl.substitute(**record.__dict__)
+
BASIC_FORMAT = "%(levelname)s:%(name)s:%(message)s"
_STYLES = {
@@ -510,7 +565,7 @@
converter = time.localtime
- def __init__(self, fmt=None, datefmt=None, style='%'):
+ def __init__(self, fmt=None, datefmt=None, style='%', validate=True):
"""
Initialize the formatter with specified format strings.
@@ -530,6 +585,9 @@
raise ValueError('Style must be one of: %s' % ','.join(
_STYLES.keys()))
self._style = _STYLES[style][0](fmt)
+ if validate:
+ self._style.validate()
+
self._fmt = self._style._fmt
self.datefmt = datefmt
diff --git a/Lib/logging/config.py b/Lib/logging/config.py
index fa1a398..cfd9311 100644
--- a/Lib/logging/config.py
+++ b/Lib/logging/config.py
@@ -666,11 +666,19 @@
dfmt = config.get('datefmt', None)
style = config.get('style', '%')
cname = config.get('class', None)
+
if not cname:
c = logging.Formatter
else:
c = _resolve(cname)
- result = c(fmt, dfmt, style)
+
+ # A TypeError would be raised if "validate" key is passed in with a formatter callable
+ # that does not accept "validate" as a parameter
+ if 'validate' in config: # if user hasn't mentioned it, the default will be fine
+ result = c(fmt, dfmt, style, config['validate'])
+ else:
+ result = c(fmt, dfmt, style)
+
return result
def configure_filter(self, config):