- Step 1: Read http://www.python.org/dev/peps/pep-0008/
- Step 2: Read http://www.python.org/dev/peps/pep-0008/ again
- Step 3: Read on
Put two newlines between top-level code (funcs, classes, etc)
Put one newline between methods in classes and anywhere else
Do not write "except:", use "except Exception:" at the very least
Include your name with TODOs as in "#TODO(termie)"
Do not shadow a built-in or reserved word. Example:
def list(): return [1, 2, 3] mylist = list() # BAD, shadows `list` built-in class Foo(object): def list(self): return [1, 2, 3] mylist = Foo().list() # OKAY, does not shadow built-in
- Do not make relative imports
- Order your imports by the full module path
- Organize your imports according to the following template
Example:
# vim: tabstop=4 shiftwidth=4 softtabstop=4 {{stdlib imports in human alphabetical order}} \n {{third-party lib imports in human alphabetical order}} \n {{quantum imports in human alphabetical order}} \n \n {{begin your code}}
Example:
import httplib import logging import random import StringIO import time import unittest import eventlet import webob.exc import quantum.api.networks from quantum.api import ports from quantum.db import models from quantum.extensions import multiport import quantum.manager from quantum import service
Example:
"""A one line docstring looks like this and ends in a period.""" """A multiline docstring has a one-line summary, less than 80 characters. Then a new paragraph after a newline that explains in more detail any general information about the function, class or method. Example usages are also great to have here if it is a complex class for function. When writing the docstring for a class, an extra line should be placed after the closing quotations. For more in-depth explanations for these decisions see http://www.python.org/dev/peps/pep-0257/ If you are going to describe parameters and return values, use Sphinx, the appropriate syntax is as follows. :param foo: the foo parameter :param bar: the bar parameter :returns: return_type -- description of the return value :returns: description of the return value :raises: AttributeError, KeyError """
If a dictionary (dict) or list object is longer than 80 characters, its items should be split with newlines. Embedded iterables should have their items indented. Additionally, the last item in the dictionary should have a trailing comma. This increases readability and simplifies future diffs.
Example:
my_dictionary = { "image": { "name": "Just a Snapshot", "size": 2749573, "properties": { "user_id": 12, "arch": "x86_64", }, "things": [ "thing_one", "thing_two", ], "status": "ACTIVE", }, }
Calls to methods 80 characters or longer should format each argument with newlines. This is not a requirement, but a guideline:
unnecessarily_long_function_name('string one', 'string two', kwarg1=constants.ACTIVE, kwarg2=['a', 'b', 'c'])
Rather than constructing parameters inline, it is better to break things up:
list_of_strings = [ 'what_a_long_string', 'not as long', ] dict_of_numbers = { 'one': 1, 'two': 2, 'twenty four': 24, } object_one.call_a_method('string three', 'string four', kwarg1=list_of_strings, kwarg2=dict_of_numbers)
In order to support multiple languages, we have a mechanism to support automatic translations of exception and log strings.
Example:
msg = _("An error occurred") raise HTTPBadRequest(explanation=msg)
If you have a variable to place within the string, first internationalize the template string then do the replacement.
Example:
msg = _("Missing parameter: %s") % ("flavor",) LOG.error(msg)
If you have multiple variables to place in the string, use keyword parameters. This helps our translators reorder parameters when needed.
Example:
msg = _("The server with id %(s_id)s has no key %(m_key)s") LOG.error(msg % {"s_id": "1234", "m_key": "imageId"})
For every new feature, unit tests should be created that both test and (implicitly) document the usage of said feature. If submitting a patch for a bug that had no unit test, a new passing unit test should be added. If a submitted bug fix does have a unit test, be sure to add a new one that fails without the patch and passes with the patch.
A number of modules from openstack-common are imported into the project.
These modules are "incubating" in openstack-common and are kept in sync with the help of openstack-common's update.py script. See:
http://wiki.openstack.org/CommonLibrary#Incubation
The copy of the code should never be directly modified here. Please always update openstack-common first and then run the script to copy the changes across.