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Thomas De Schampheleire
pytest migration: introduce TestControllerPytest

In order to allow tests to benefit from pytest specific functionality, like
fixtures, they can no longer derive from unittest.TestCase. What's more,
while they can derive from any user-defined class, none of the classes
involved (the test class itself nor any of the base classes) can have an
__init__ method.

Converting all tests from unittest-style to pytest-style in one commit is
not realistic. Hence, a more gradual approach is needed.

Most existing test classes derive from TestController, which in turn derives
from BaseTestCase, which derives from unittest.TestCase. Some test classes
derive directly from BaseTestCase.
Supporting both unittest-style and pytest-style from TestController directly
is not possible: pytest-style _cannot_ and unittest-style _must_ derive from
unittest.TestCase. Thus, in any case, an extra level in the class hierarchy
is needed (TestController deriving from Foo and from unittest.TestCase;
pytest-style test classes would then directly derive from Foo).

The requirement that pytest-style test classes cannot have an __init__
method anywhere in the class hierarchy imposes another restriction that
makes it difficult to support both unittest-style and pytest-style test
classes with one class. Any init code needs to be placed in another method
than __init__ and be called explicitly when the test class is initialized.
For unittest-style test classes this would naturally be done with a
setupClass method, but several test classes already use that. Thus, there
would need to be explicit 'super' calls from the test classes. This is
technically possible but not very nice.

A more transparent approach (from the existing test classes point of view),
implemented by this patch, works as follows:
- the implementation of the existing TestController class is now put under
a new class BaseTestController. To accomodate pytest, the __init__ method
is renamed init.
- contrary to the original TestController, BaseTestController does not
derive from BaseTestCase (and neither from unittest.TestCase). Instead,
the 'new' TestController derives both from BaseTestCase, which is
untouched, and from BaseTestController.
- TestController has an __init__ method that calls the base classes'
__init__ methods and the renamed 'init' method of BaseTestController.
- a new class TestControllerPytest is introduced that derives from
BaseTestController but not from BaseTestCase. It uses a pytest fixture to
automatically call the setup functionality previously provided by
BaseTestCase and also calls 'init' on BaseTestController. This means a
little code duplication but is hard to avoid.

The app setup fixture is scoped on the test method, which means that the app
is recreated for every test (unlike for the unittest-style tests where the
app is created per test class). This has the advantage of detecting current
inter-test dependencies and thus improve the health of our test suite. This
in turn is one step closer to allowing parallel test execution.

The unittest-style assert methods (assertEqual, assertIn, ...) do not exist
for pytest-style tests. To avoid having to change all existing test cases
upfront, provide transitional implementations of these methods. The
conversion of the unittest asserts to the pytest/python asserts can happen
gradually over time.
.. _installation_iis:

=====================================================================
Installing Kallithea on Microsoft Internet Information Services (IIS)
=====================================================================

The following is documented using IIS 7/8 terminology. There should be nothing
preventing you from applying this on IIS 6 well.

.. note::

    For the best security, it is strongly recommended to only host the site over
    a secure connection, e.g. using TLS.


Prerequisites
-------------

Apart from the normal requirements for Kallithea, it is also necessary to get an
ISAPI-WSGI bridge module, e.g. isapi-wsgi.


Installation
------------

The following assumes that your Kallithea is at ``c:\inetpub\kallithea``, and
will be served from the root of its own website. The changes to serve it in its
own virtual folder will be noted where appropriate.

Application pool
^^^^^^^^^^^^^^^^

Make sure that there is a unique application pool for the Kallithea application
with an identity that has read access to the Kallithea distribution.

The application pool does not need to be able to run any managed code. If you
are using a 32-bit Python installation, then you must enable 32-bit program in
the advanced settings for the application pool; otherwise Python will not be able
to run on the website and neither will Kallithea.

.. note::

    The application pool can be the same as an existing application pool,
    as long as the Kallithea requirements are met by the existing pool.

ISAPI handler
^^^^^^^^^^^^^

The ISAPI handler can be generated using::

    paster install-iis my.ini --root=/

This will generate a ``dispatch.py`` file in the current directory that contains
the necessary components to finalize an installation into IIS. Once this file
has been generated, it is necessary to run the following command due to the way
that ISAPI-WSGI is made::

    python2 dispatch.py install

This accomplishes two things: generating an ISAPI compliant DLL file,
``_dispatch.dll``, and installing a script map handler into IIS for the
``--root`` specified above pointing to ``_dispatch.dll``.

The ISAPI handler is registered to all file extensions, so it will automatically
be the one handling all requests to the specified root. When the website starts
the ISAPI handler, it will start a thread pool managed wrapper around the paster
middleware WSGI handler that Kallithea runs within and each HTTP request to the
site will be processed through this logic henceforth.

Authentication with Kallithea using IIS authentication modules
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

The recommended way to handle authentication with Kallithea using IIS is to let
IIS handle all the authentication and just pass it to Kallithea.

To move responsibility into IIS from Kallithea, we need to configure Kallithea
to let external systems handle authentication and then let Kallithea create the
user automatically. To do this, access the administration's authentication page
and enable the ``kallithea.lib.auth_modules.auth_container`` plugin. Once it is
added, enable it with the ``REMOTE_USER`` header and check *Clean username*.
Finally, save the changes on this page.

Switch to the administration's permissions page and disable anonymous access,
otherwise Kallithea will not attempt to use the authenticated user name. By
default, Kallithea will populate the list of users lazily as they log in. Either
disable external auth account activation and ensure that you pre-populate the
user database with an external tool, or set it to *Automatic activation of
external account*. Finally, save the changes.

The last necessary step is to enable the relevant authentication in IIS, e.g.
Windows authentication.


Troubleshooting
---------------

Typically, any issues in this setup will either be entirely in IIS or entirely
in Kallithea (or Kallithea's WSGI/paster middleware). Consequently, two
different options for finding issues exist: IIS' failed request tracking which
is great at finding issues until they exist inside Kallithea, at which point the
ISAPI-WSGI wrapper above uses ``win32traceutil``, which is part of ``pywin32``.

In order to dump output from WSGI using ``win32traceutil`` it is sufficient to
type the following in a console window::

    python2 -m win32traceutil

and any exceptions occurring in the WSGI layer and below (i.e. in the Kallithea
application itself) that are uncaught, will be printed here complete with stack
traces, making it a lot easier to identify issues.