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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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