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| 1 # Copyright (c) 2009-2010 Google, Inc. | 1 # Copyright (c) 2009-2010 Google, Inc. |
| 2 # This program is free software; you can redistribute it and/or modify it under | 2 # This program is free software; you can redistribute it and/or modify it under |
| 3 # the terms of the GNU General Public License as published by the Free Software | 3 # the terms of the GNU General Public License as published by the Free Software |
| 4 # Foundation; either version 2 of the License, or (at your option) any later | 4 # Foundation; either version 2 of the License, or (at your option) any later |
| 5 # version. | 5 # version. |
| 6 # | 6 # |
| 7 # This program is distributed in the hope that it will be useful, but WITHOUT | 7 # This program is distributed in the hope that it will be useful, but WITHOUT |
| 8 # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS | 8 # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS |
| 9 # FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. | 9 # FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. |
| 10 # | 10 # |
| 11 # You should have received a copy of the GNU General Public License along with | 11 # You should have received a copy of the GNU General Public License along with |
| 12 # this program; if not, write to the Free Software Foundation, Inc., | 12 # this program; if not, write to the Free Software Foundation, Inc., |
| 13 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. | 13 # 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 14 """checker for use of Python logging | 14 """checker for use of Python logging |
| 15 """ | 15 """ |
| 16 | 16 |
| 17 import astroid | 17 from logilab import astng |
| 18 from pylint import checkers | 18 from pylint import checkers |
| 19 from pylint import interfaces | 19 from pylint import interfaces |
| 20 from pylint.checkers import utils | 20 from pylint.checkers import utils |
| 21 from pylint.checkers.utils import check_messages | 21 |
| 22 | 22 |
| 23 MSGS = { | 23 MSGS = { |
| 24 'W1201': ('Specify string format arguments as logging function parameters', | 24 'W1201': ('Specify string format arguments as logging function parameters', |
| 25 'logging-not-lazy', | 25 'Used when a logging statement has a call form of ' |
| 26 'Used when a logging statement has a call form of ' | 26 '"logging.<logging method>(format_string % (format_args...))". ' |
| 27 '"logging.<logging method>(format_string % (format_args...))". ' | 27 'Such calls should leave string interpolation to the logging ' |
| 28 'Such calls should leave string interpolation to the logging ' | 28 'method itself and be written ' |
| 29 'method itself and be written ' | 29 '"logging.<logging method>(format_string, format_args...)" ' |
| 30 '"logging.<logging method>(format_string, format_args...)" ' | 30 'so that the program may avoid incurring the cost of the ' |
| 31 'so that the program may avoid incurring the cost of the ' | 31 'interpolation in those cases in which no message will be ' |
| 32 'interpolation in those cases in which no message will be ' | 32 'logged. For more, see ' |
| 33 'logged. For more, see ' | 33 'http://www.python.org/dev/peps/pep-0282/.'), |
| 34 'http://www.python.org/dev/peps/pep-0282/.'), | |
| 35 'E1200': ('Unsupported logging format character %r (%#02x) at index %d', | 34 'E1200': ('Unsupported logging format character %r (%#02x) at index %d', |
| 36 'logging-unsupported-format', | |
| 37 'Used when an unsupported format character is used in a logging\ | 35 'Used when an unsupported format character is used in a logging\ |
| 38 statement format string.'), | 36 statement format string.'), |
| 39 'E1201': ('Logging format string ends in middle of conversion specifier', | 37 'E1201': ('Logging format string ends in middle of conversion specifier', |
| 40 'logging-format-truncated', | |
| 41 'Used when a logging statement format string terminates before\ | 38 'Used when a logging statement format string terminates before\ |
| 42 the end of a conversion specifier.'), | 39 the end of a conversion specifier.'), |
| 43 'E1205': ('Too many arguments for logging format string', | 40 'E1205': ('Too many arguments for logging format string', |
| 44 'logging-too-many-args', | |
| 45 'Used when a logging format string is given too few arguments.'), | 41 'Used when a logging format string is given too few arguments.'), |
| 46 'E1206': ('Not enough arguments for logging format string', | 42 'E1206': ('Not enough arguments for logging format string', |
| 47 'logging-too-few-args', | |
| 48 'Used when a logging format string is given too many arguments'), | 43 'Used when a logging format string is given too many arguments'), |
| 49 } | 44 } |
| 50 | 45 |
| 51 | 46 |
| 52 CHECKED_CONVENIENCE_FUNCTIONS = set([ | 47 CHECKED_CONVENIENCE_FUNCTIONS = set([ |
| 53 'critical', 'debug', 'error', 'exception', 'fatal', 'info', 'warn', | 48 'critical', 'debug', 'error', 'exception', 'fatal', 'info', 'warn', |
| 54 'warning']) | 49 'warning']) |
| 55 | 50 |
| 56 | 51 |
| 57 class LoggingChecker(checkers.BaseChecker): | 52 class LoggingChecker(checkers.BaseChecker): |
| 58 """Checks use of the logging module.""" | 53 """Checks use of the logging module.""" |
| 59 | 54 |
| 60 __implements__ = interfaces.IAstroidChecker | 55 __implements__ = interfaces.IASTNGChecker |
| 61 name = 'logging' | 56 name = 'logging' |
| 62 msgs = MSGS | 57 msgs = MSGS |
| 63 | 58 |
| 64 options = (('logging-modules', | |
| 65 {'default' : ('logging',), | |
| 66 'type' : 'csv', | |
| 67 'metavar' : '<comma separated list>', | |
| 68 'help' : 'Logging modules to check that the string format ' | |
| 69 'arguments are in logging function parameter format'} | |
| 70 ), | |
| 71 ) | |
| 72 | |
| 73 def visit_module(self, unused_node): | 59 def visit_module(self, unused_node): |
| 74 """Clears any state left in this checker from last module checked.""" | 60 """Clears any state left in this checker from last module checked.""" |
| 75 # The code being checked can just as easily "import logging as foo", | 61 # The code being checked can just as easily "import logging as foo", |
| 76 # so it is necessary to process the imports and store in this field | 62 # so it is necessary to process the imports and store in this field |
| 77 # what name the logging module is actually given. | 63 # what name the logging module is actually given. |
| 78 self._logging_names = set() | 64 self._logging_name = None |
| 79 logging_mods = self.config.logging_modules | |
| 80 | |
| 81 self._logging_modules = set(logging_mods) | |
| 82 self._from_imports = {} | |
| 83 for logging_mod in logging_mods: | |
| 84 parts = logging_mod.rsplit('.', 1) | |
| 85 if len(parts) > 1: | |
| 86 self._from_imports[parts[0]] = parts[1] | |
| 87 | |
| 88 def visit_from(self, node): | |
| 89 """Checks to see if a module uses a non-Python logging module.""" | |
| 90 try: | |
| 91 logging_name = self._from_imports[node.modname] | |
| 92 for module, as_name in node.names: | |
| 93 if module == logging_name: | |
| 94 self._logging_names.add(as_name or module) | |
| 95 except KeyError: | |
| 96 pass | |
| 97 | 65 |
| 98 def visit_import(self, node): | 66 def visit_import(self, node): |
| 99 """Checks to see if this module uses Python's built-in logging.""" | 67 """Checks to see if this module uses Python's built-in logging.""" |
| 100 for module, as_name in node.names: | 68 for module, as_name in node.names: |
| 101 if module in self._logging_modules: | 69 if module == 'logging': |
| 102 self._logging_names.add(as_name or module) | 70 if as_name: |
| 71 self._logging_name = as_name |
| 72 else: |
| 73 self._logging_name = 'logging' |
| 103 | 74 |
| 104 @check_messages(*(MSGS.keys())) | |
| 105 def visit_callfunc(self, node): | 75 def visit_callfunc(self, node): |
| 106 """Checks calls to logging methods.""" | 76 """Checks calls to (simple forms of) logging methods.""" |
| 107 def is_logging_name(): | 77 if (not isinstance(node.func, astng.Getattr) |
| 108 return (isinstance(node.func, astroid.Getattr) and | 78 or not isinstance(node.func.expr, astng.Name) |
| 109 isinstance(node.func.expr, astroid.Name) and | 79 or node.func.expr.name != self._logging_name): |
| 110 node.func.expr.name in self._logging_names) | 80 return |
| 81 self._check_convenience_methods(node) |
| 82 self._check_log_methods(node) |
| 111 | 83 |
| 112 def is_logger_class(): | 84 def _check_convenience_methods(self, node): |
| 113 try: | 85 """Checks calls to logging convenience methods (like logging.warn).""" |
| 114 for inferred in node.func.infer(): | 86 if node.func.attrname not in CHECKED_CONVENIENCE_FUNCTIONS: |
| 115 if isinstance(inferred, astroid.BoundMethod): | 87 return |
| 116 parent = inferred._proxied.parent | 88 if node.starargs or node.kwargs or not node.args: |
| 117 if (isinstance(parent, astroid.Class) and | 89 # Either no args, star args, or double-star args. Beyond the |
| 118 (parent.qname() == 'logging.Logger' or | 90 # scope of this checker. |
| 119 any(ancestor.qname() == 'logging.Logger' | 91 return |
| 120 for ancestor in parent.ancestors()))): | 92 if isinstance(node.args[0], astng.BinOp) and node.args[0].op == '%': |
| 121 return True, inferred._proxied.name | 93 self.add_message('W1201', node=node) |
| 122 except astroid.exceptions.InferenceError: | 94 elif isinstance(node.args[0], astng.Const): |
| 123 pass | 95 self._check_format_string(node, 0) |
| 124 return False, None | |
| 125 | 96 |
| 126 if is_logging_name(): | 97 def _check_log_methods(self, node): |
| 127 name = node.func.attrname | |
| 128 else: | |
| 129 result, name = is_logger_class() | |
| 130 if not result: | |
| 131 return | |
| 132 self._check_log_method(node, name) | |
| 133 | |
| 134 def _check_log_method(self, node, name): | |
| 135 """Checks calls to logging.log(level, format, *format_args).""" | 98 """Checks calls to logging.log(level, format, *format_args).""" |
| 136 if name == 'log': | 99 if node.func.attrname != 'log': |
| 137 if node.starargs or node.kwargs or len(node.args) < 2: | |
| 138 # Either a malformed call, star args, or double-star args. Beyon
d | |
| 139 # the scope of this checker. | |
| 140 return | |
| 141 format_pos = 1 | |
| 142 elif name in CHECKED_CONVENIENCE_FUNCTIONS: | |
| 143 if node.starargs or node.kwargs or not node.args: | |
| 144 # Either no args, star args, or double-star args. Beyond the | |
| 145 # scope of this checker. | |
| 146 return | |
| 147 format_pos = 0 | |
| 148 else: | |
| 149 return | 100 return |
| 150 | 101 if node.starargs or node.kwargs or len(node.args) < 2: |
| 151 if isinstance(node.args[format_pos], astroid.BinOp) and node.args[format
_pos].op == '%': | 102 # Either a malformed call, star args, or double-star args. Beyond |
| 152 self.add_message('logging-not-lazy', node=node) | 103 # the scope of this checker. |
| 153 elif isinstance(node.args[format_pos], astroid.Const): | 104 return |
| 154 self._check_format_string(node, format_pos) | 105 if isinstance(node.args[1], astng.BinOp) and node.args[1].op == '%': |
| 106 self.add_message('W1201', node=node) |
| 107 elif isinstance(node.args[1], astng.Const): |
| 108 self._check_format_string(node, 1) |
| 155 | 109 |
| 156 def _check_format_string(self, node, format_arg): | 110 def _check_format_string(self, node, format_arg): |
| 157 """Checks that format string tokens match the supplied arguments. | 111 """Checks that format string tokens match the supplied arguments. |
| 158 | 112 |
| 159 Args: | 113 Args: |
| 160 node: AST node to be checked. | 114 node: AST node to be checked. |
| 161 format_arg: Index of the format string in the node arguments. | 115 format_arg: Index of the format string in the node arguments. |
| 162 """ | 116 """ |
| 163 num_args = _count_supplied_tokens(node.args[format_arg + 1:]) | 117 num_args = self._count_supplied_tokens(node.args[format_arg + 1:]) |
| 164 if not num_args: | 118 if not num_args: |
| 165 # If no args were supplied, then all format strings are valid - | 119 # If no args were supplied, then all format strings are valid - |
| 166 # don't check any further. | 120 # don't check any further. |
| 167 return | 121 return |
| 168 format_string = node.args[format_arg].value | 122 format_string = node.args[format_arg].value |
| 169 if not isinstance(format_string, basestring): | 123 if not isinstance(format_string, basestring): |
| 170 # If the log format is constant non-string (e.g. logging.debug(5)), | 124 # If the log format is constant non-string (e.g. logging.debug(5)), |
| 171 # ensure there are no arguments. | 125 # ensure there are no arguments. |
| 172 required_num_args = 0 | 126 required_num_args = 0 |
| 173 else: | 127 else: |
| 174 try: | 128 try: |
| 175 keyword_args, required_num_args = \ | 129 keyword_args, required_num_args = \ |
| 176 utils.parse_format_string(format_string) | 130 utils.parse_format_string(format_string) |
| 177 if keyword_args: | 131 if keyword_args: |
| 178 # Keyword checking on logging strings is complicated by | 132 # Keyword checking on logging strings is complicated by |
| 179 # special keywords - out of scope. | 133 # special keywords - out of scope. |
| 180 return | 134 return |
| 181 except utils.UnsupportedFormatCharacter, ex: | 135 except utils.UnsupportedFormatCharacter, e: |
| 182 char = format_string[ex.index] | 136 c = format_string[e.index] |
| 183 self.add_message('logging-unsupported-format', node=node, | 137 self.add_message('E1200', node=node, args=(c, ord(c), e.index)) |
| 184 args=(char, ord(char), ex.index)) | |
| 185 return | 138 return |
| 186 except utils.IncompleteFormatString: | 139 except utils.IncompleteFormatString: |
| 187 self.add_message('logging-format-truncated', node=node) | 140 self.add_message('E1201', node=node) |
| 188 return | 141 return |
| 189 if num_args > required_num_args: | 142 if num_args > required_num_args: |
| 190 self.add_message('logging-too-many-args', node=node) | 143 self.add_message('E1205', node=node) |
| 191 elif num_args < required_num_args: | 144 elif num_args < required_num_args: |
| 192 self.add_message('logging-too-few-args', node=node) | 145 self.add_message('E1206', node=node) |
| 193 | 146 |
| 147 def _count_supplied_tokens(self, args): |
| 148 """Counts the number of tokens in an args list. |
| 194 | 149 |
| 195 def _count_supplied_tokens(args): | 150 The Python log functions allow for special keyword arguments: func, |
| 196 """Counts the number of tokens in an args list. | 151 exc_info and extra. To handle these cases correctly, we only count |
| 152 arguments that aren't keywords. |
| 197 | 153 |
| 198 The Python log functions allow for special keyword arguments: func, | 154 Args: |
| 199 exc_info and extra. To handle these cases correctly, we only count | 155 args: List of AST nodes that are arguments for a log format string. |
| 200 arguments that aren't keywords. | |
| 201 | 156 |
| 202 Args: | 157 Returns: |
| 203 args: List of AST nodes that are arguments for a log format string. | 158 Number of AST nodes that aren't keywords. |
| 204 | 159 """ |
| 205 Returns: | 160 return sum(1 for arg in args if not isinstance(arg, astng.Keyword)) |
| 206 Number of AST nodes that aren't keywords. | |
| 207 """ | |
| 208 return sum(1 for arg in args if not isinstance(arg, astroid.Keyword)) | |
| 209 | 161 |
| 210 | 162 |
| 211 def register(linter): | 163 def register(linter): |
| 212 """Required method to auto-register this checker.""" | 164 """Required method to auto-register this checker.""" |
| 213 linter.register_checker(LoggingChecker(linter)) | 165 linter.register_checker(LoggingChecker(linter)) |
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