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#!/usr/bin/env python |
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"""\ |
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Logging Statement Modifier - replace logging calls with pass (or vice versa) |
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Author: David Underhill <[email protected]> |
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Version: 1.00 (06-Feb-2010) |
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This script parses a Python file and comments out logging statements, replacing |
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them with a pass statement (or vice versa). The purpose of commenting out these |
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statements is to improve performance. Even if logging is disabled, arguments to |
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logging method calls must still be evaluated, which can be expensive. |
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This tool handles most common cases: |
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* Log statements may span multiple lines. |
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* Custom logging levels may be added (LEVELS, LEVEL_VALUES). |
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* Integral logging levels & named logging levels (DEBUG, etc.) are recognized. |
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* Logging statements log(), debug(), ..., critical() are all recognized. |
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* Statements with unrecognized logging levels will be left as-is. |
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* 'logging' is the assumed logging module name (LOGGING_MODULE_NAME). |
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However, its ability to parse files is limited: |
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* It only operates on logging statements in the form logging.log(<level>, ...) |
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and logging.<level>(...). |
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* The <level> must either be an integral constant or contain one of the names |
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from the LEVELS constant below. |
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* If a logging statement is made, it is assumed that no other statement is |
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made on the same line as logging statement (except for statements made in |
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between the open and close parenthesis of the logging call). For example, |
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a semi-colon and then a second statement on the same line as a logging call |
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will not be handled properly. |
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* Logging methods must be called through SOME module, e.g., logging.log(), not |
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just log(). |
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* For simplicity, undoing the commenting process relies on a comment left by |
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the program on the pass statements it adds when commenting out logging |
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statements. (So don't change the comment it outputs by the pass statement). |
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To run this command on all of the Python files in a particular folder and its |
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sub-folders at once, try this (replace '/path/to' as appropriate): |
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find . -name '*.py' | xargs -i{} /path/to/logging_statement_modifier.py {} |
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""" |
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import logging |
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from optparse import OptionParser |
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import re |
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import sys |
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# logging level names and values |
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LEVELS = ['DEBUG', 'INFO', 'WARN', 'WARNING', 'ERROR', 'CRITICAL'] |
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LEVEL_VALUES = [logging.DEBUG, logging.INFO, logging.WARN, logging.WARNING, logging.ERROR, logging.CRITICAL] |
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LEVELS_DICT = dict(zip(LEVELS, LEVEL_VALUES)) |
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# names of methods in the logging module which perform logging |
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LOGGING_METHODS_OF_INTEREST = ['log', 'debug', 'info', 'warn', 'warning', 'error', 'critical'] |
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# name of the logging module |
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LOGGING_MODULE_NAME = 'logging' |
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# this matches logging.<method>([<first_arg>,] |
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# STR_RE_LOGGING_CALL = r'%s.(\w+)[(](([^,\r\n]+),)?' % LOGGING_MODULE_NAME |
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STR_RE_LOGGING_CALL = r'\b(' + '|'.join(LOGGING_METHODS_OF_INTEREST) + r')[(](([^,\r\n]+),)?' |
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# contents of a pass line (not including prefixed whitespace) |
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PASS_LINE_CONTENTS = 'pass # replaces next logging statement\n' |
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# Match a logging call (must only be prefixed with whitespace). Capture groups |
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# include the whitespace, the logging method called, and the first argument if |
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# possible |
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RE_LOGGING_START = re.compile(r'^(\s+)' + STR_RE_LOGGING_CALL) |
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RE_LOGGING_START_IN_COMMENT = re.compile(r'^(\s+)#' + STR_RE_LOGGING_CALL) |
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def main(argv=sys.argv[1:]): |
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"""Parses the command line comments.""" |
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usage = 'usage: %prog [options] FILE\n\n' + __doc__ |
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parser = OptionParser(usage) |
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# options |
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parser.add_option("-f", "--force", |
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action='store_true', default=False, |
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help="make changes even if they cannot undone before saving the new file") |
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parser.add_option("-m", "--min_level", |
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default='NONE', |
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help="minimum level of logging statements to modify [default: no minimum]") |
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parser.add_option("-M", "--max_level", |
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default='NONE', |
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help="maximum level of logging statements to modify [default: no maximum]") |
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parser.add_option("-o", "--output-file", |
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default=None, |
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help="where to output the result [default: overwrite the input file]") |
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parser.add_option("-r", "--restore", |
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action='store_true', default=False, |
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help="restore logging statements previously commented out and replaced with pass statements") |
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parser.add_option("-v", "--verbose", |
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action='store_true', default=False, |
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help="print informational messages about changes made") |
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(options, args) = parser.parse_args(argv) |
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if len(args) != 1: |
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parser.error("expected 1 argument but got %d arguments: %s" % (len(args), ' '.join(args))) |
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input_fn = args[0] |
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if not options.output_file: |
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options.output_file = input_fn |
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# validate min/max level |
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LEVEL_CHOICES = LEVELS + ['NONE'] |
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min_level_value = 0 if options.min_level == 'NONE' else get_level_value(options.min_level) |
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if options.min_level is None: |
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parser.error("min level must be an integer or one of these values: %s" % ', '.join(LEVEL_CHOICES)) |
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max_level_value = sys.maxint if options.max_level == 'NONE' else get_level_value(options.max_level) |
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if options.max_level is None: |
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parser.error("max level must be an integer or one of these values: %s" % ', '.join(LEVEL_CHOICES)) |
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if options.verbose: |
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logging.getLogger().setLevel(logging.INFO) |
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try: |
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return modify_logging(input_fn, options.output_file, |
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min_level_value, max_level_value, |
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options.restore, options.force) |
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except IOError as e: |
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logging.error(str(e)) |
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return -1 |
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# matches two main groups: 1) leading whitespace and 2) all following text |
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RE_LINE_SPLITTER_COMMENT = re.compile(r'^(\s*)((.|\n)*)$') |
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def comment_lines(lines): |
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"""Comment out the given list of lines and return them. The hash mark will |
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be inserted before the first non-whitespace character on each line.""" |
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ret = [] |
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for line in lines: |
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ws_prefix, rest, ignore = RE_LINE_SPLITTER_COMMENT.match(line).groups() |
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ret.append(ws_prefix + '#' + rest) |
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return ''.join(ret) |
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# matches two main groups: 1) leading whitespace and 2) all following text |
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RE_LINE_SPLITTER_UNCOMMENT = re.compile(r'^(\s*)#((.|\n)*)$') |
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def uncomment_lines(lines): |
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"""Uncomment the given list of lines and return them. The first hash mark |
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following any amount of whitespace will be removed on each line.""" |
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ret = [] |
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for line in lines: |
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ws_prefix, rest, ignore = RE_LINE_SPLITTER_UNCOMMENT.match(line).groups() |
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ret.append(ws_prefix + rest) |
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return ''.join(ret) |
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def first_arg_to_level_name(arg): |
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"""Decide what level the argument specifies and return it. The argument |
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must contain (case-insensitive) one of the values in LEVELS or be an integer |
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constant. Otherwise None will be returned.""" |
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try: |
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return int(arg) |
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except ValueError: |
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arg = arg.upper() |
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for level in LEVELS: |
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if level in arg: |
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return level |
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return None |
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def get_level_value(level): |
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"""Returns the logging value associated with a particular level name. The |
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argument must be present in LEVELS_DICT or be an integer constant. |
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Otherwise None will be returned.""" |
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try: |
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# integral constants also work: they are the level value |
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return int(level) |
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except ValueError: |
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try: |
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return LEVELS_DICT[level.upper()] |
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except KeyError: |
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logging.warning("level '%s' cannot be translated to a level value (not present in LEVELS_DICT)" % level) |
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return None |
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def get_logging_level(logging_stmt, commented_out=False): |
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"""Determines the level of logging in a given logging statement. The string |
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representing this level is returned. False is returned if the method is |
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not a logging statement and thus has no level. None is returned if a level |
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should have been found but wasn't.""" |
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regexp = RE_LOGGING_START_IN_COMMENT if commented_out else RE_LOGGING_START |
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ret = regexp.match(logging_stmt) |
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_, method_name, _, first_arg = ret.groups() |
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if method_name not in LOGGING_METHODS_OF_INTEREST: |
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logging.debug('skipping uninteresting logging call: %s' % method_name) |
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return False |
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if method_name != 'log': |
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return method_name |
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# if the method name did not specify the level, we must have a first_arg to extract the level from |
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if not first_arg: |
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logging.warning("logging.log statement found but we couldn't extract the first argument") |
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return None |
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# extract the level of logging from the first argument to the log() call |
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level = first_arg_to_level_name(first_arg) |
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if level is None: |
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logging.warning("arg does not contain any known level '%s'\n" % first_arg) |
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return None |
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return level |
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def level_is_between(level, min_level_value, max_level_value): |
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"""Returns True if level is between the specified min or max, inclusive.""" |
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level_value = get_level_value(level) |
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if level_value is None: |
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# unknown level value |
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return False |
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return level_value >= min_level_value and level_value <= max_level_value |
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def split_call(lines, open_paren_line=0): |
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"""Returns a 2-tuple where the first element is the list of lines from the |
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first open paren in lines to the matching closed paren. The second element |
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is all remaining lines in a list.""" |
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num_open = 0 |
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num_closed = 0 |
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for i, line in enumerate(lines): |
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c = line.count('(') |
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num_open += c |
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if not c and i==open_paren_line: |
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raise Exception('Exception open parenthesis in line %d but there is not one there: %s' % (i, str(lines))) |
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num_closed += line.count(')') |
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if num_open == num_closed: |
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return (lines[:i+1], lines[i+1:]) |
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print ''.join(lines) |
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raise Exception('parenthesis are mismatched (%d open, %d closed found)' % (num_open, num_closed)) |
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def modify_logging(input_fn, output_fn, min_level_value, max_level_value, restore, force): |
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"""Modifies logging statements in the specified file.""" |
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# read in all the lines |
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logging.info('reading in %s' % input_fn) |
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fh = open(input_fn, 'r') |
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lines = fh.readlines() |
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fh.close() |
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original_contents = ''.join(lines) |
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if restore: |
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forwards = restore_logging |
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backwards = disable_logging |
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else: |
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forwards = disable_logging |
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backwards = restore_logging |
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# apply the requested action |
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new_contents = forwards(lines, min_level_value, max_level_value) |
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# quietly check to see if we can undo what we just did (if not, the text |
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# contains something we cannot translate [bug or limitation with this code]) |
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logging.disable(logging.CRITICAL) |
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new_contents_undone = backwards(new_contents.splitlines(True), min_level_value, max_level_value) |
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logging.disable(logging.DEBUG) |
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if original_contents != new_contents_undone: |
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base_str = 'We are unable to revert this action as expected' |
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if force: |
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logging.warning(base_str + " but -f was specified so we'll do it anyway.") |
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else: |
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logging.error(base_str + ', so we will not do it in the first place. Pass -f to override this and make the change anyway.') |
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return -1 |
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logging.info('writing the new contents to %s' % output_fn) |
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fh = open(output_fn, 'w') |
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fh.write(new_contents) |
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fh.close() |
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logging.info('done!') |
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return 0 |
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def check_level(logging_stmt, logging_stmt_is_commented_out, min_level_value, max_level_value): |
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"""Extracts the level of the logging statement and returns True if the |
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level falls betwen min and max_level_value. If the level cannot be |
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extracted, then a warning is logged.""" |
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level = get_logging_level(logging_stmt, logging_stmt_is_commented_out) |
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if level is None: |
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logging.warning('skipping logging statement because the level could not be extracted: %s' % logging_stmt.strip()) |
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return False |
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elif level is False: |
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return False |
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elif level_is_between(level, min_level_value, max_level_value): |
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return True |
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else: |
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logging.debug('keep this one as is (not in the specified level range): %s' % logging_stmt.strip()) |
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return False |
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def disable_logging(lines, min_level_value, max_level_value): |
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"""Disables logging statements in these lines whose logging level falls |
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between the specified minimum and maximum levels.""" |
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output = '' |
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while lines: |
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line = lines[0] |
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ret = RE_LOGGING_START.match(line) |
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if not ret: |
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# no logging statement here, so just leave the line as-is and keep going |
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output += line |
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lines = lines[1:] |
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else: |
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# a logging call has started: find all the lines it includes and those it does not |
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logging_lines, remaining_lines = split_call(lines) |
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lines = remaining_lines |
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logging_stmt = ''.join(logging_lines) |
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# replace the logging statement if its level falls b/w min and max |
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if not check_level(logging_stmt, False, min_level_value, max_level_value): |
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output += logging_stmt |
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else: |
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# comment out this logging statement and replace it with pass |
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prefix_ws = ret.group(1) |
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pass_stmt = prefix_ws + PASS_LINE_CONTENTS |
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commented_out_logging_lines = comment_lines(logging_lines) |
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new_lines = pass_stmt + commented_out_logging_lines |
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logging.info('replacing:\n%s\nwith this:\n%s' % (logging_stmt.rstrip(), new_lines.rstrip())) |
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output += new_lines |
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return output |
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def restore_logging(lines, min_level_value, max_level_value): |
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"""Re-enables logging statements in these lines whose logging level falls |
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between the specified minimum and maximum levels and which were disabled |
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by disable_logging() before.""" |
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output = '' |
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while lines: |
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line = lines[0] |
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if line.lstrip() != PASS_LINE_CONTENTS: |
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# not our pass statement here, so just leave the line as-is and keep going |
320
|
|
|
output += line |
321
|
|
|
lines = lines[1:] |
322
|
|
|
else: |
323
|
|
|
# a logging call will start on the next line: find all the lines it includes and those it does not |
324
|
|
|
logging_lines, remaining_lines = split_call(lines[1:]) |
325
|
|
|
lines = remaining_lines |
326
|
|
|
logging_stmt = ''.join(logging_lines) |
327
|
|
|
original_lines = line + logging_stmt |
328
|
|
|
|
329
|
|
|
# replace the logging statement if its level falls b/w min and max |
330
|
|
|
if not check_level(logging_stmt, True, min_level_value, max_level_value): |
331
|
|
|
output += logging_stmt |
332
|
|
|
else: |
333
|
|
|
# uncomment_lines of this logging statement and remove the pass line |
334
|
|
|
uncommented_logging_lines = uncomment_lines(logging_lines) |
335
|
|
|
logging.info('replacing:\n%s\nwith this:\n%s' % (original_lines.rstrip(), uncommented_logging_lines.rstrip())) |
336
|
|
|
output += uncommented_logging_lines |
337
|
|
|
return output |
338
|
|
|
|
339
|
|
|
if __name__ == "__main__": |
340
|
|
|
logging.basicConfig(format='%(levelname)s: %(message)s', level=logging.WARN) |
341
|
|
|
sys.exit(main()) |
342
|
|
|
|