Convert commented out print statements to logging calls - Python

I'm hacking on a framwork right now, and I'd like to use logging. However, the developers of the framework have been using print statements to debug, a开发者_JAVA技巧nd they are all commented out for the production release. I was wondering, does anyone know of a regex to find these, and convert them to logging calls.

This is what I was thinking so far:

import re
import sys
import StringIO

if not len(sys.argv) != 2:
    print 'Syntax: printtologging.py file_to_process'

regex = r'#print (?P<debugstring>*)$'

output = StringIO.StringIO('w+')

def replace(match_object):
    return 'logging.debug({0})'.format(match_object.group_dict['debugstring'])

with open(sys.argv[1]) as f:
    output.writelines([re.sub(regex, replace, line) for line in f.readlines()])

output.seek(0)
print output.read()

Though that dosn't seem to be working. My regex's are far from brilliant, could anyone help?

---

If you want to do it in Python, consider using the fileinput module:

import fileinput
import sys
import re

def convert(paths):
    for line in fileinput.input(paths, inplace=True, backup='~'):
        line=re.sub(r'#\s*print\s*(.*)',r'logging.debug(\1)',line)
        sys.stdout.write(line)

if __name__=='__main__':
    convert(sys.argv[1:])

You could call the script this way

% print2log.py *.py

It converts the scripts in-place, and makes a backup file which ends with ~.

Note that the regex converts

#print 'foo'   -->  logging.debug('foo')

but adds an extra set of parentheses if the print statement already had one:

#print('foo')  --> logging.debug(('foo'))

It also screws up multi-line print statements:

#print('''foo        logging.debug(('''foo)
#bar''')       -->   #bar''')

Fixing this is a much harder problem, requiring parsing the comments and using something smarter than regex, which can't handle nested parentheses properly. I think you could do it with tokenize, and with code similar in spirit to reindent.py, but it would take some time and thought to get it right.

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If all the print statements are already contained in brackets, then sed will do the job:

sed -i s/#print/logging\.debug/g files_to_process

---

You can achieve the same with sed

sed -i.old -E -e "s/#+[[:space:]]*print (.*)/logging.debug(\1)/" FILE

I made your regex a bit more robust. It now also matches if multiple # and/or whitespace between # and print are present.

Note that it still doesn't handle some edge cases like

#print 'foo'; print'bar'

-i.old activates in-place editing with a backup written to FILE.old. Omit the .old if you don't want backups, i.e. sed -i -E ...

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An alternative to this is to leave the print statements in place and to replace sys.stdout with a file like object that does logging.