7.0 KiB
Glance Style Commandments =======================
- 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
General
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 name anything the same name as a built-in or reserved word
Use the "is not" operator when testing for unequal identities. Example:
if not X is Y: # BAD, intended behavior is ambiguous pass if X is not Y: # OKAY, intuitive passUse the "not in" operator for evaluating membership in a collection. Example:
if not X in Y: # BAD, intended behavior is ambiguous pass if X not in Y: # OKAY, intuitive pass if not (X in Y or X in Z): # OKAY, still better than all those 'not's pass
Imports
- 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
{{glance imports in human alphabetical order}}
\n
\n
{{begin your code}}Human Alphabetical Order Examples
Example:
import httplib
import logging
import random
import StringIO
import time
import unittest
import eventlet
import webob.exc
import glance.api.middleware
from glance.api import images
from glance.auth import users
import glance.common
from glance.endpoint import cloud
from glance import testDocstrings
Docstrings are required for all functions and methods.
Docstrings should ONLY use triple-double-quotes
(""")
Single-line docstrings should NEVER have extraneous whitespace between enclosing triple-double-quotes.
INCORRECT :
""" There is some whitespace between the enclosing quotes :( """CORRECT :
"""There is no whitespace between the enclosing quotes :)"""Docstrings that span more than one line should look like this:
Example:
"""
Start the docstring on the line following the opening triple-double-quote
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
"""DO NOT leave an extra newline before the closing triple-double-quote.
Dictionaries/Lists
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",
},
}Calling Methods
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)Internationalization (i18n) Strings
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"})Creating Unit Tests
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.
Commit Messages
Using a common format for commit messages will help keep our git history readable. Follow these guidelines:
First, provide a brief summary of 50 characters or less. Summaries of greater then 72 characters will be rejected by the gate.
The first line of the commit message should provide an accurate description of the change, not just a reference to a bug or blueprint. It must be followed by a single blank line.
Following your brief summary, provide a more detailed description of the patch, manually wrapping the text at 72 characters. This description should provide enough detail that one does not have to refer to external resources to determine its high-level functionality.
Once you use 'git review', two lines will be appended to the commit message: a blank line followed by a 'Change-Id'. This is important to correlate this commit with a specific review in Gerrit, and it should not be modified.
For further information on constructing high quality commit messages, and how to split up commits into a series of changes, consult the project wiki:
oslo-incubator
A number of modules from oslo-incubator are imported into the project.
These modules are "incubating" in oslo-incubator and are kept in sync with the help of oslo's update.py script. See:
The copy of the code should never be directly modified here. Please always update oslo-incubator first and then run the script to copy the changes across.
Logging
Use __name__ as the name of your logger and name your module-level logger objects 'LOG':
LOG = logging.getLogger(__name__)