274 lines
8.3 KiB
ReStructuredText
274 lines
8.3 KiB
ReStructuredText
Savanna Style Commandments
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==========================
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(Based on OpenStack Nova Style Commandments)
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- Step 1: Read http://www.python.org/dev/peps/pep-0008/
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- Step 2: Read http://www.python.org/dev/peps/pep-0008/ again
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- Step 3: Read on
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General
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-------
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- Put two newlines between top-level code (funcs, classes, etc)
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- Use only UNIX style newlines ("\n"), not Windows style ("\r\n")
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- Put one newline between methods in classes and anywhere else
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- Long lines should be wrapped in parentheses
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in preference to using a backslash for line continuation.
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- Do not write "except:", use "except Exception:" at the very least
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- Include your name with TODOs as in "#TODO(termie)"
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- Do not shadow a built-in or reserved word. Example::
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def list():
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return [1, 2, 3]
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mylist = list() # BAD, shadows `list` built-in
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class Foo(object):
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def list(self):
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return [1, 2, 3]
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mylist = Foo().list() # OKAY, does not shadow built-in
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- Use the "is not" operator when testing for unequal identities. Example::
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if not X is Y: # BAD, intended behavior is ambiguous
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pass
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if X is not Y: # OKAY, intuitive
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pass
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- Use the "not in" operator for evaluating membership in a collection. Example::
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if not X in Y: # BAD, intended behavior is ambiguous
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pass
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if X not in Y: # OKAY, intuitive
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pass
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if not (X in Y or X in Z): # OKAY, still better than all those 'not's
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pass
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Imports
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-------
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- Do not import objects, only modules (*)
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- Do not import more than one module per line (*)
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- Do not use wildcard ``*`` import (*)
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- Do not make relative imports
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- Direct work with db should be placed into the savanna/storage/storage module
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- Order your imports by the full module path
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- Organize your imports according to the following template
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(*) exceptions are:
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- imports from ``sqlalchemy`` package
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Example::
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# vim: tabstop=4 shiftwidth=4 softtabstop=4
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{{stdlib imports in human alphabetical order}}
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\n
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{{third-party lib imports in human alphabetical order}}
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\n
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{{savanna imports in human alphabetical order}}
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\n
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\n
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{{begin your code}}
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Human Alphabetical Order Examples
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---------------------------------
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Example::
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import time
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from jinja2 import Environment
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from jinja2 import PackageLoader
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from oslo.config import cfg
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import paramiko
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from savanna.openstack.common import log as logging
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from savanna.storage.db import DB
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from savanna.storage.storage import update_cluster_status
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Docstrings
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----------
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Example::
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"""A one line docstring looks like this and ends in a period."""
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"""A multi line docstring has a one-line summary, less than 80 characters.
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Then a new paragraph after a newline that explains in more detail any
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general information about the function, class or method. Example usages
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are also great to have here if it is a complex class for function.
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When writing the docstring for a class, an extra line should be placed
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after the closing quotations. For more in-depth explanations for these
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decisions see http://www.python.org/dev/peps/pep-0257/
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If you are going to describe parameters and return values, use Sphinx, the
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appropriate syntax is as follows.
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:param foo: the foo parameter
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:param bar: the bar parameter
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:returns: return_type -- description of the return value
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:returns: description of the return value
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:raises: AttributeError, KeyError
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"""
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Dictionaries/Lists
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------------------
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If a dictionary (dict) or list object is longer than 80 characters, its items
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should be split with newlines. Embedded iterables should have their items
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indented. Additionally, the last item in the dictionary should have a trailing
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comma. This increases readability and simplifies future diffs.
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Example::
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my_dictionary = {
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"image": {
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"name": "Just a Snapshot",
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"size": 2749573,
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"properties": {
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"user_id": 12,
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"arch": "x86_64",
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},
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"things": [
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"thing_one",
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"thing_two",
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],
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"status": "ACTIVE",
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},
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}
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Calling Methods
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---------------
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Calls to methods 80 characters or longer should format each argument with
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newlines. This is not a requirement, but a guideline::
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unnecessarily_long_function_name('string one',
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'string two',
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kwarg1=constants.ACTIVE,
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kwarg2=['a', 'b', 'c'])
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Rather than constructing parameters inline, it is better to break things up::
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list_of_strings = [
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'what_a_long_string',
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'not as long',
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]
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dict_of_numbers = {
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'one': 1,
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'two': 2,
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'twenty four': 24,
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}
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object_one.call_a_method('string three',
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'string four',
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kwarg1=list_of_strings,
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kwarg2=dict_of_numbers)
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Internationalization (i18n) Strings
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-----------------------------------
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In order to support multiple languages, we have a mechanism to support
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automatic translations of exception and log strings.
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Example::
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msg = _("An error occurred")
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raise HTTPBadRequest(explanation=msg)
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If you have a variable to place within the string, first internationalize the
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template string then do the replacement.
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Example::
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msg = _("Missing parameter: %s") % ("flavor",)
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LOG.error(msg)
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If you have multiple variables to place in the string, use keyword parameters.
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This helps our translators reorder parameters when needed.
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Example::
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msg = _("The server with id %(s_id)s has no key %(m_key)s")
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LOG.error(msg % {"s_id": "1234", "m_key": "imageId"})
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Creating Unit Tests
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-------------------
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For every new feature, unit tests should be created that both test and
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(implicitly) document the usage of said feature. If submitting a patch for a
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bug that had no unit test, a new passing unit test should be added. If a
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submitted bug fix does have a unit test, be sure to add a new one that fails
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without the patch and passes with the patch.
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For more information on creating unit tests and utilizing the testing
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infrastructure in Savanna, please read savanna/tests/README.rst.
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Running Tests
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-------------
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The testing system is based on a combination of tox and nosetests. The
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canonical approach to running tests is to simply run the command `tox`. This
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will create virtual environments, populate them with dependencies and run all
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of the tests that OpenStack CI systems run. Behind the scenes, tox is running
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`nosetests` with some configs that you can find in `setup.cfg` and `tox.ini`.
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It is also possible to run the tests inside of a virtual environment
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you have created, or it is possible that you have all of the dependencies
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installed locally already. In this case, you can interact with the nosetests
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command directly.
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openstack-common
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----------------
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A number of modules from openstack-common are imported into the project.
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These modules are "incubating" in openstack-common and are kept in sync
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with the help of openstack-common's update.py script. See:
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http://wiki.openstack.org/CommonLibrary#Incubation
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The copy of the code should never be directly modified here. Please
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always update openstack-common first and then run the script to copy
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the changes across.
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Commit Messages
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---------------
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Using a common format for commit messages will help keep our git history
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readable. Follow these guidelines:
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First, provide a brief summary of 50 characters or less. Summaries
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of greater then 72 characters will be rejected by the gate.
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The first line of the commit message should provide an accurate
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description of the change, not just a reference to a bug or
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blueprint. It must be followed by a single blank line.
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Following your brief summary, provide a more detailed description of
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the patch, manually wrapping the text at 72 characters. This
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description should provide enough detail that one does not have to
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refer to external resources to determine its high-level functionality.
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Once you use 'git review', two lines will be appended to the commit
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message: a blank line followed by a 'Change-Id'. This is important
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to correlate this commit with a specific review in Gerrit, and it
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should not be modified.
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For further information on constructing high quality commit messages,
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and how to split up commits into a series of changes, consult the
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project wiki:
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http://wiki.openstack.org/GitCommitMessages
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