Coding Guidelines

We use PEP.8 as base of our coding guidelines, with some additions and changes. Those changes are mostly due to the personal preferences of the current developers of RADICAL-Pilot (RP). Such preferences can be discussed, revised and agreed upon during RP development meetings. Deviations from PEP.8 pertains to:

• Enabling visual alignment of code;

• preferring ' over " (but use " when that avoids escapes);

• preferring %-based string expansion over string.format;

• allowing short names for loop variables.

In all other regards, we expect PEP.8 compliance.

Example:

#!/usr/bin/env python3

import sys
import time
import pprint

import radical.utils as ru
import radical.saga  as rs
import radical.pilot as rp


# ------------------------------------------------------------------------------
# constants
# (we use delimiting lines like above to separate code sections, classes, etc.)
#
STATE_ONE   = 'one'
STATE_TWO   = 'two'
STATE_THREE = 'three'


# ------------------------------------------------------------------------------
#
# this class is nothing special, but its mine.
#
class MyClass(object):
    '''
    This method demonstrates what deviations from PEP.8 are accepted in RP.
    '''

    # --------------------------------------------------------------------------
    #
    def __init__(self):

        self._state   = STATE_ONE
        self._created = time.time()
        self._worker  = ru.Thread()
        self._config  = {'title'         : 'hello darkness',
                         'subtitle'      : 'my old friend',
                         'super_category': 'example'}


    # --------------------------------------------------------------------------
    #
    def method(self, arg_1='default_1', arg_2='default_2',
                     arg_3='default_3', arg_4='default_4'):
        '''
        method documentation
        '''

        if arg_1 == 'default_1' and \
           arg_2 != 'default_2':
            print 'this is unexpectedly indented (%s: %s)' % (arg_1, arg_2)

        # we allow one letter names for temporary loop variables
        for i in range(4):
            print "It's a simply i [%d]" % i

        # strangely indendet clauses
        if   arg3 == arg4: print 'haleluja'               # because why not
        elif arg2 == arg4: print 'praise the space'       # loooots of space
        else             : print 'clickediclickediclick'  # clickedispace!

        pprint.some_formatting_method(mode='radical', align='fancy',
                                      enforce=False,  encourage=True)


# ------------------------------------------------------------------------------

This is our flake8 configuration, which should transfer to other pep8 linters:

[flake8]
exclude          = .git,__pycache__,docs,build,dist,setup.py
max-complexity   = 10
max-line-length  = 80
per-file-ignores =
     # imported but unused, star-import, unmatched F*
     __init__.py: F401, F403, X100
ignore           =
     # module level import location
     E402,
     # space before/after operator
     E221, E222,E251,
     # multiple spaces after/after keyword
     E271, E272,
     # line too long
     E501,
     # whitespace before/after ...
     E203, E202, E231, E241, E211, E116, E127,
     # same indent
     E129,
     # comment indent not mod(4)
     E114,
     # cont line indentation
     E128, E126, E124, E125, E131,
     # blank lines
     W391, E301, E303,
     # multiple statements on one line
     E701, E704,
     # space before bracket
     C0326,
     # trailing whitespace
     W291,
     # Complex methods
     C901,
     # Do not use bare 'except'
     E722,
     # allow line breaks after binary operators
     W504,
     # allow lambda assignment (used for partial callbacks)
     E731