Snippet for adding PEP8 and JSHint validation to your Fabric fabfile.

fabfile.py

from fabric.api import (task, local, lcd)


"""
The pep8 and jshint tasks return False if errors were found and True if found.
The show_errors parameter controls if the method prints out the errors returned by
the checker program.

Requirements: Install pep8 and jshint, so that they can be run from the command line
 - pip install pep8
 - npm -g install jshint
"""
@task
def pep8(show_errors=False):
  with(lcd(os.path.join(os.path.dirname(__file__), APP_DIR))):
    return handle_error_checking_cmd(
      "find . -name '*.py' -not -iwholename "
      "'*migrations*' -exec pep8 {} \;",
      show_errors,
      "PEP8"
    )


@task
def jshint(show_errors=False):
  with(nested(lcd(os.path.join(os.path.dirname(__file__), STATIC_JS_DIR)),
               settings(warn_only=True))):
    return handle_error_checking_cmd(
      "jshint . | grep ': line *'",
      show_errors,
      "JSHint"
    )


# Helper function to avoid repetition
def handle_error_checking_cmd(cmd, show_errors, error_name=''):
  errors = local(cmd, capture=True)
  error_list = errors.splitlines()
  error_count = len(error_list)
  if show_errors:
    print(errors)
  if error_count > 0:
    print("You have %s %s errors" % (error_count, error_name))
    return False
  else:
    print("You have no %s errors :D" % (error_name, ))
    return True

I assume we're to replace STATIC_JS_DIR with a target to validate, right?

Also, where does nested come from?