pre-commit

#!/usr/bin/env python

"""
Git pre-commit hook for checking Python code quality. The hook requires pylint
to check the code quality.

AUTHOR:
    Sebastian Dahlgren <sebastian.dahlgren@gmail.com>

VERSION:
    1.0.0

LICENSE:
    Apache License 2.0
    http://www.apache.org/licenses/LICENSE-2.0.html
"""

#######################################
#
# CONFIGURATION
#
#######################################

# The lowest allowed score (should be a float between 0.00 and 10.00)
LIMIT = 10.00

# pylint command to run
PYLINT = 'pylint'

# where to look for options
PYLINTRC = '.pylintrc'

# Custom pylint command line parameters. See pylint --help for more info
# E.g.
# PYLINT_PARAMS = '--rcfile=/path/to/project/pylint.rc'
PYLINT_PARAMS = ''

#######################################
#
# CODE BELOW
#
#######################################

import os
import re
import sys
import subprocess
import ConfigParser

def get_list_of_committed_files():
    """
    Returns a list of files about to be commited.
    """
    files = []
    # pylint: disable=E1103
    output = subprocess.check_output(
        'git diff-index --cached HEAD'.split())
    for result in output.split('\n'):
        if result != '':
            result = result.split()
            if result[4] in ['A', 'M']:
                files.append(result[5])

    return files


def checker():
    """
    Main function doing the checks
    """
    global PYLINT, PYLINT_PARAMS, LIMIT

    # List of checked files and their results
    python_files = []

    # Set the exit code
    exit_code = 0

    # Find Python files
    for filename in get_list_of_committed_files():
        # Check the file extension
        if filename[-3:] == '.py':
            python_files.append((filename, None))
            continue

        # Check the first line for a python shebang
        try:
            with open(filename, 'r') as file_handle:
                first_line = file_handle.readline()
            if 'python' in first_line and '#!' in first_line:
                python_files.append((filename, None))
        except IOError:
            print 'File not found (probably deleted): %s\t\tSKIPPED' % filename

    # Don't do anything if there are no Python files
    if len(python_files) == 0:
        sys.exit(0)

    # Load any pre-commit-hooks options from a .pylintrc file (if there is one)

    if os.path.exists('.pylintrc'):
        conf = ConfigParser.SafeConfigParser()
        conf.read('.pylintrc')
        if conf.has_option('pre-commit-hook', 'command'):
            PYLINT = conf.get('pre-commit-hook', 'command')
        if conf.has_option('pre-commit-hook', 'params'):
            PYLINT_PARAMS += ' ' + conf.get('pre-commit-hook', 'params')
        if conf.has_option('pre-commit-hook', 'limit'):
            LIMIT += ' ' + conf.get('pre-commit-hook', 'limit')

    # Pylint Python files
    i = 1
    regexp = re.compile(r'^Your\ code\ has\ been\ rated\ at\ (\-?[0-9\.]+)/10')
    for python_file, score in python_files:
        # Allow __init__.py files to be completely empty
        if os.path.basename(python_file) == '__init__.py':
            if os.stat(python_file).st_size == 0:
                print 'Skipping pylint on %s (empty __init__.py)..\tSKIPPED' % (
                    python_file)

                # Bump parsed files
                i += 1
                continue

        # Set the initial score
        score = 0.00

        # skipping test files
        if python_file.startswith('src/slidelint/tests'):
            continue

        # Start pylinting
        sys.stdout.write("Running pylint on %s (file %i/%i)..\t" % (
            python_file, i, len(python_files)))
        sys.stdout.flush()
        try:
            command = [PYLINT]

            if PYLINT_PARAMS:
                command += PYLINT_PARAMS.split()

            if '--rcfile' not in PYLINT_PARAMS:
                if os.path.exists('.pylintrc'):
                    command.append('--rcfile=.pylintrc')

            command.append(python_file)

            proc = subprocess.Popen(
                command,
                stdout=subprocess.PIPE,
                stderr=subprocess.PIPE)
            out, _ = proc.communicate()
        except OSError as err:
            print "\nAn error occurred. Is pylint installed?"
            sys.exit(1)

        # Check for the result
        # pylint: disable=E1103
        for line in out.split('\n'):
            match = re.match(regexp, line)
            if match:
                score = float(match.group(1))

        # Verify the score
        if score >= float(LIMIT):
            status = 'PASSED'
        else:
            status = 'FAILED'
            exit_code = 1

        # Add some output
        print '%.2f/10.00\t%s' % (score, status)

        # Bump parsed files
        i += 1

    sys.exit(exit_code)

if __name__ == '__main__':
    checker()

sys.exit(1)