Changeset - 2db16cda05ba
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Mads Kiilerich - 9 years ago 2017-05-14 21:20:12
mads@kiilerich.com
docs: clarify that Session usually should be called - methods should not be used directly

Documentation based on clarification by Søren Løvborg:

Session is the factory/singleton manager, which tracks the current session (per
thread). To end the current session entirely and destroy the Session object, we
call remove on the manager (Session.remove()). (A new session will be created
on-demand.)

Session() returns the current session for the active thread (or creates a new
session, if there's none). commit is a method of the SQLAlchemy Session class,
thus called as Session().commit() ... it's a method call on the current Session
object, not the session factory/manager.

SQLAlchemy may have some hackery to allow Session.commit() to be called, and
the call automatically redirect to the actual Session object... but that's a
hack and should be avoided.

TL;DR: for remove, call it on Session; for everything else, call it on
Session().
1 file changed with 7 insertions and 1 deletions:
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docs/contributing.rst
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.. _contributing:
 

	
 
=========================
 
Contributing to Kallithea
 
=========================
 

	
 
Kallithea is developed and maintained by its users. Please join us and scratch
 
your own itch.
 

	
 

	
 
Infrastructure
 
--------------
 

	
 
The main repository is hosted on Our Own Kallithea (aka OOK) at
 
https://kallithea-scm.org/repos/kallithea/, our self-hosted instance
 
of Kallithea.
 

	
 
For now, we use Bitbucket_ for `pull requests`_ and `issue tracking`_. The
 
issue tracker is for tracking bugs, not for support, discussion, or ideas --
 
please use the `mailing list`_ or :ref:`IRC <readme>` to reach the community.
 

	
 
We use Weblate_ to translate the user interface messages into languages other
 
than English. Join our project on `Hosted Weblate`_ to help us.
 
To register, you can use your Bitbucket or GitHub account. See :ref:`translations`
 
for more details.
 

	
 

	
 
Getting started
 
---------------
 

	
 
To get started with development::
 

	
 
        hg clone https://kallithea-scm.org/repos/kallithea
 
        cd kallithea
 
        virtualenv ../kallithea-venv
 
        source ../kallithea-venv/bin/activate
 
        pip install --upgrade pip setuptools
 
        pip install -e .
 
        gearbox make-config my.ini
 
        gearbox setup-db -c my.ini --user=user --email=user@example.com --password=password --repos=/tmp
 
        gearbox serve -c my.ini --reload &
 
        firefox http://127.0.0.1:5000/
 

	
 
You can also start out by forking https://bitbucket.org/conservancy/kallithea
 
on Bitbucket_ and create a local clone of your own fork.
 

	
 

	
 
Running tests
 
-------------
 

	
 
After finishing your changes make sure all tests pass cleanly. Install the test
 
dependencies, then run the testsuite by invoking ``py.test`` from the
 
project root::
 

	
 
    pip install -r dev_requirements.txt
 
    py.test
 

	
 
Note that testing on Python 2.6 also requires ``unittest2``.
 

	
 
Note that on unix systems, the temporary directory (``/tmp`` or where
 
``$TMPDIR`` points) must allow executable files; Git hooks must be executable,
 
and the test suite creates repositories in the temporary directory. Linux
 
systems with /tmp mounted noexec will thus fail.
 

	
 
You can also use ``tox`` to run the tests with all supported Python versions
 
(currently Python 2.6--2.7).
 

	
 
When running tests, Kallithea uses `kallithea/tests/test.ini` and populates the
 
SQLite database specified there.
 

	
 
It is possible to avoid recreating the full test database on each invocation of
 
the tests, thus eliminating the initial delay. To achieve this, run the tests as::
 

	
 
    gearbox serve -c kallithea/tests/test.ini --pid-file=test.pid --daemon
 
    KALLITHEA_WHOOSH_TEST_DISABLE=1 KALLITHEA_NO_TMP_PATH=1 py.test
 
    kill -9 $(cat test.pid)
 

	
 
In these commands, the following variables are used::
 

	
 
    KALLITHEA_WHOOSH_TEST_DISABLE=1 - skip whoosh index building and tests
 
    KALLITHEA_NO_TMP_PATH=1 - disable new temp path for tests, used mostly for testing_vcs_operations
 

	
 
You can run individual tests by specifying their path as argument to py.test.
 
py.test also has many more options, see `py.test -h`. Some useful options
 
are::
 

	
 
    -k EXPRESSION         only run tests which match the given substring
 
                          expression. An expression is a python evaluable
 
                          expression where all names are substring-matched
 
                          against test names and their parent classes. Example:
 
    -x, --exitfirst       exit instantly on first error or failed test.
 
    --lf                  rerun only the tests that failed at the last run (or
 
                          all if none failed)
 
    --ff                  run all tests but run the last failures first. This
 
                          may re-order tests and thus lead to repeated fixture
 
                          setup/teardown
 
    --pdb                 start the interactive Python debugger on errors.
 
    -s, --capture=no      don't capture stdout (any stdout output will be
 
                          printed immediately)
 

	
 

	
 
Contribution guidelines
 
-----------------------
 

	
 
Kallithea is GPLv3 and we assume all contributions are made by the
 
committer/contributor and under GPLv3 unless explicitly stated. We do care a
 
lot about preservation of copyright and license information for existing code
 
that is brought into the project.
 

	
 
Contributions will be accepted in most formats -- such as pull requests on
 
Bitbucket, something hosted on your own Kallithea instance, or patches sent by
 
email to the `kallithea-general`_ mailing list.
 

	
 
When contributing via Bitbucket, please make your fork of
 
https://bitbucket.org/conservancy/kallithea/ `non-publishing`_ -- it is one of
 
the settings on "Repository details" page. This ensures your commits are in
 
"draft" phase and makes it easier for you to address feedback and for project
 
maintainers to integrate your changes.
 

	
 
.. _non-publishing: https://www.mercurial-scm.org/wiki/Phases#Publishing_Repository
 

	
 
Make sure to test your changes both manually and with the automatic tests
 
before posting.
 

	
 
We care about quality and review and keeping a clean repository history. We
 
might give feedback that requests polishing contributions until they are
 
"perfect". We might also rebase and collapse and make minor adjustments to your
 
changes when we apply them.
 

	
 
We try to make sure we have consensus on the direction the project is taking.
 
Everything non-sensitive should be discussed in public -- preferably on the
 
mailing list.  We aim at having all non-trivial changes reviewed by at least
 
one other core developer before pushing. Obvious non-controversial changes will
 
be handled more casually.
 

	
 
For now we just have one official branch ("default") and will keep it so stable
 
that it can be (and is) used in production. Experimental changes should live
 
elsewhere (for example in a pull request) until they are ready.
 

	
 

	
 
Coding guidelines
 
-----------------
 

	
 
We don't have a formal coding/formatting standard. We are currently using a mix
 
of Mercurial's (https://www.mercurial-scm.org/wiki/CodingStyle), pep8, and
 
consistency with existing code. Run ``scripts/run-all-cleanup`` before
 
committing to ensure some basic code formatting consistency.
 

	
 
We support both Python 2.6.x and 2.7.x and nothing else. For now we don't care
 
about Python 3 compatibility.
 

	
 
We try to support the most common modern web browsers. IE9 is still supported
 
to the extent it is feasible, IE8 is not.
 

	
 
We primarily support Linux and OS X on the server side but Windows should also work.
 

	
 
HTML templates should use 2 spaces for indentation ... but be pragmatic. We
 
should use templates cleverly and avoid duplication. We should use reasonable
 
semantic markup with element classes and IDs that can be used for styling and testing.
 
We should only use inline styles in places where it really is semantic (such as
 
``display: none``).
 

	
 
JavaScript must use ``;`` between/after statements. Indentation 4 spaces. Inline
 
multiline functions should be indented two levels -- one for the ``()`` and one for
 
``{}``.
 
Variables holding jQuery objects should be named with a leading ``$``.
 

	
 
Commit messages should have a leading short line summarizing the changes. For
 
bug fixes, put ``(Issue #123)`` at the end of this line.
 

	
 
Use American English grammar and spelling overall. Use `English title case`_ for
 
page titles, button labels, headers, and 'labels' for fields in forms.
 

	
 
.. _English title case: https://en.wikipedia.org/wiki/Capitalization#Title_case
 

	
 
Template helpers (that is, everything in ``kallithea.lib.helpers``)
 
should only be referenced from templates. If you need to call a
 
helper from the Python code, consider moving the function somewhere
 
else (e.g. to the model).
 

	
 
Notes on the SQLAlchemy session
 
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 

	
 
Each HTTP request runs inside an independent SQLAlchemy session (as well
 
as in an independent database transaction). Database model objects
 
as in an independent database transaction). ``Session`` is the session manager
 
and factory. ``Session()`` will create a new session on-demand or return the
 
current session for the active thread. Many database operations are methods on
 
such session instances - only ``Session.remove()`` should be called directly on
 
the manager.
 

	
 
Database model objects
 
(almost) always belong to a particular SQLAlchemy session, which means
 
that SQLAlchemy will ensure that they're kept in sync with the database
 
(but also means that they cannot be shared across requests).
 

	
 
Objects can be added to the session using ``Session().add``, but this is
 
rarely needed:
 

	
 
* When creating a database object by calling the constructor directly,
 
  it must explicitly be added to the session.
 

	
 
* When creating an object using a factory function (like
 
  ``create_repo``), the returned object has already (by convention)
 
  been added to the session, and should not be added again.
 

	
 
* When getting an object from the session (via ``Session().query`` or
 
  any of the utility functions that look up objects in the database),
 
  it's already part of the session, and should not be added again.
 
  SQLAlchemy monitors attribute modifications automatically for all
 
  objects it knows about and syncs them to the database.
 

	
 
SQLAlchemy also flushes changes to the database automatically; manually
 
calling ``Session().flush`` is usually only necessary when the Python
 
code needs the database to assign an "auto-increment" primary key ID to
 
a freshly created model object (before flushing, the ID attribute will
 
be ``None``).
 

	
 
TurboGears2 DebugBar
 
^^^^^^^^^^^^^^^^^^^^
 

	
 
It is possible to enable the TurboGears2-provided DebugBar_, a toolbar overlayed
 
over the Kallithea web interface, allowing you to see:
 

	
 
* timing information of the current request, including profiling information
 
* request data, including GET data, POST data, cookies, headers and environment
 
  variables
 
* a list of executed database queries, including timing and result values
 

	
 
DebugBar is only activated when ``debug = true`` is set in the configuration
 
file. This is important, because the DebugBar toolbar will be visible for all
 
users, and allow them to see information they should not be allowed to see. Like
 
is anyway the case for ``debug = true``, do not use this in production!
 

	
 
To enable DebugBar, install ``tgext.debugbar`` and ``kajiki`` (typically via
 
``pip``) and restart Kallithea (in debug mode).
 

	
 

	
 
"Roadmap"
 
---------
 

	
 
We do not have a road map but are waiting for your contributions. Refer to the
 
wiki_ for some ideas of places we might want to go -- contributions in these
 
areas are very welcome.
 

	
 

	
 
Thank you for your contribution!
 
--------------------------------
 

	
 

	
 
.. _Weblate: http://weblate.org/
 
.. _issue tracking: https://bitbucket.org/conservancy/kallithea/issues?status=new&status=open
 
.. _pull requests: https://bitbucket.org/conservancy/kallithea/pull-requests
 
.. _bitbucket: http://bitbucket.org/
 
.. _mailing list: http://lists.sfconservancy.org/mailman/listinfo/kallithea-general
 
.. _kallithea-general: http://lists.sfconservancy.org/mailman/listinfo/kallithea-general
 
.. _Hosted Weblate: https://hosted.weblate.org/projects/kallithea/kallithea/
 
.. _wiki: https://bitbucket.org/conservancy/kallithea/wiki/Home
 
.. _DebugBar: https://github.com/TurboGears/tgext.debugbar
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