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CKAN is an open-source DMS (data management system) for powering data hubs and data portals. CKAN makes it easy to publish, share and use data. It powers, and among many other sites.
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Comprehensive Knowledge Archive Network (CKAN) Software.

See :mod:`ckan.__long_description__` for more information.

Developer Installation

These are instructions to get developing with CKAN. Instructions for deploying
CKAN to a server are at: :doc:`deployment` (doc/deployment.rst).

Before you start it may be worth checking CKAN has passed the auto build and
tests. See:

1. Ensure these packages are installed:

   =====================  ===============================================
   Package                Description
   =====================  ===============================================
   mercurial              Source control
   python-dev             Python interpreter v2.5 - v2.7 and dev headers
   postgresql             PostgreSQL database
   libpq-dev              PostgreSQL library
   python-psycopg2        PostgreSQL python module
   libxml2-dev            XML library development files
   libxslt-dev            XSLT library development files
   python-virtualenv      Python virtual environments
   wget                   Command line tool for downloading from the web
   build-essential        Tools for building source code
   git-core               Git source control (for getting MarkupSafe src)
   subversion             Subversion source control (for pyutilib)
   =====================  ===============================================

   For Ubuntu you can install these like so:
       sudo apt-get install build-essential libxml2-dev libxslt-dev 
       sudo apt-get install wget mercurial postgresql libpq-dev git-core
       sudo apt-get install python-dev python-psycopg2 python-virtualenv
       sudo apt-get install subversion
2. Create a python virtual environment
   In your home directory run the command below. It is currently important to
   call your virtual environment ``pyenv`` so that the automated deployment tools
   work correctly.
       cd ~
       virtualenv pyenv
   .. tip ::
       If you don't have a ``python-virtualenv`` package in your distribution
       you can get a ```` script from within the 
       `virtualenv source distribution <>`_
       and then run ``python pyenv`` instead.
       To help with automatically installing CKAN dependencies we use a tool
       called ``pip``. Make sure you have activated your environment (see step 3)
       and then install it from an activated shell like this:
           easy_install pip
3. Activate your virtual environment

   To work with CKAN it is best to adjust your shell settings so that your
   shell uses the virtual environment you just created. You can do this like


       . pyenv/bin/activate

   When your shell is activated you will see the prompt change to something
   like this:


       (pyenv)[ckan@host ~/]$

   An activated shell looks in your virtual environment first when choosing
   which commands to run. If you enter ``python`` now it will actually 
   run ``~/pyenv/bin/python`` which is what you want.

4. Install CKAN code and required Python packages into the new environment

   First you'll need to install CKAN. For the latest version run:


       pip install --ignore-installed -e hg+

   CKAN has a set of dependencies it requires which you should install too:


       pip install --ignore-installed -r pyenv/src/ckan/requires/lucid_missing.txt -r pyenv/src/ckan/requires/lucid_conflict.txt

   The ``--ignore-installed`` option ensures ``pip`` installs software into
   this virtual environment even if it is already present on the system.

   If you are using Ubuntu Lucid you can install the rest of the dependencies
   from the system versions like this:


       sudo apt-get install python-psycopg2 python-lxml python-sphinx 
       sudo apt-get install python-pylons python-formalchemy python-repoze.who
       sudo apt-get install python-repoze.who-plugins python-tempita python-zope.interface
   If you are not using Ubuntu Lucid you'll still need to install all the
   dependencies that would have been met in the ``apt-get install`` command
   at the start. You can do so like this:


       pip install --ignore-installed -r pyenv/src/ckan/requires/lucid_present.txt
   This will take a **long** time. Particularly the install of the ``lxml``

   At this point you will need to deactivate and then re-activate your
   virtual environment to ensure that all the scripts point to the correct

       . pyenv/bin/activate

5. Setup a PostgreSQL database

  List existing databases:


      psql -l

  It is advisable to ensure that the encoding of databases is 'UTF8', or 
  internationalisation may be a problem. Since changing the encoding of PostgreSQL
  may mean deleting existing databases, it is suggested that this is fixed before
  continuing with the CKAN install.

  Next you'll need to create a database user if one doesn't already exist.

  .. tip ::

      If you choose a database name, user or password which are different from those 
      suggested below then you'll need to update the configuration file you'll create in
      the next step.

  Here we choose ``ckantest`` as the database and ``ckanuser`` as the user:


      sudo -u postgres createuser -S -D -R -P ckantest

  It should prompt you for a new password for the CKAN data in the database.
  It is suggested you enter ``pass`` for the password.

  Now create the database, which we'll call ``ckantest`` (the last argument):


      sudo -u postgres createdb -O ckantest ckantest

6. Create a CKAN config file

  Make sure you are in an activated environment (see step 3) so that Python
  Paste and other modules are put on the python path (your command prompt will
  start with ``(pyenv)`` if you have) then change into the ``ckan`` directory
  which will have been created when you installed CKAN in step 4 and create the
  config file ``development.ini`` using Paste:


      cd pyenv/src/ckan
      paster make-config ckan development.ini

  You can give your config file a different name but the tests will expect you
  to have used ``development.ini`` so it is strongly recommended you use this
  name, at least to start with.

  If you used a different database name or password when creating the database
  in step 5 you'll need to now edit ``development.ini`` and change the
  ``sqlalchemy.url`` line, filling in the database name, user and password you used.

      sqlalchemy.url = postgresql://ckantest:pass@localhost/ckantest

  Other configuration, such as setting the language of the site or editing the
  visual theme are described in :doc:`configuration` (doc/configuration.rst)  

  .. caution ::

     Advanced users: If you are using CKAN's fab file capability you currently need to create
     your config file as ``pyenv/`` so you will probably have 
     ignored the advice about creating a ``development.ini`` file in the 
     ``pyenv/src/ckan`` directory. This is fine but CKAN probably won't be 
     able to find your ``who.ini`` file. To fix this edit ``pyenv/``, 
     search for the line ``who.config_file = %(here)s/who.ini`` and change it
     to ``who.config_file = who.ini``.

     We are moving to a new deployment system where this incompatibility 
     will be fixed.

7. Create database tables

  Now that you have a configuration file that has the correct settings for
  your database, you'll need to create the tables. Make sure you are still in an
  activated environment with ``(pyenv)`` at the front of the command prompt and
  then from the ``pyenv/src/ckan`` directory run this command:


       paster db init

  You should see ``Initialising DB: SUCCESS``. If you are not in the
  ``pyenv/src/ckan`` directory or you don't have an activated shell, the command
  will not work.

  If the command prompts for a password it is likely you haven't set up the 
  database configuration correctly in step 6.

8. Create the cache directory

  You need to create the Pylon's cache directory specified by 'cache_dir' 
  in the config file.

  (from the ``pyenv/src/ckan`` directory):


      mkdir data

9. Run the CKAN webserver

  NB If you've started a new shell, you'll have to activate the environment
  again first - see step 3.

  (from the pyenv/src/ckan directory):


      paster serve development.ini

10. Point your web browser at:

    The CKAN homepage should load without problem.

If you ever want to upgrade to a more recent version of CKAN, read the
``UPGRADE.txt`` file in ``pyenv/src/ckan/``.


Setting up to test

Make sure you've created a config file: ``pyenv/ckan/development.ini``

Ensure you have activated the environment::

    . pyenv/bin/activate

Install nose into your virtual environment if you haven't already::

    pip install --ignore-installed nose

At this point you will need to deactivate and then re-activate your
virtual environment to ensure that all the scripts point to the correct


    . pyenv/bin/activate

Running developer tests

Here's how you start the quick development tests::

    cd pyenv/src/ckan
    nosetests ckan/tests --ckan

You *must* run the tests from the CKAN directory as shown above, otherwise the
``--ckan`` plugin won't work correctly. 

.. caution ::

   By default, the test run is 'quick and dirty' - only good enough as a check
   before committing code. See the next section for improved ways of running tests.

Test configurations

The default way to run tests is defined in test.ini (which is the default config file for nose - change it with option "--with-pylons"). This specifies to use Sqlite and sets faster_db_test_hacks, which are compromises.


    cd pyenv/src/ckan
    nosetests ckan/tests --ckan

Although Sqlite is useful for testing a large proportion of CKAN, actually in deployment, CKAN must run with PostgreSQL. Running the tests against PosgreSQL is slower but more thorough for two reasons:
       1. You test subtleties of PostgreSQL
       2. CKAN's default search relies on PostgreSQL's custom Full Text Search, so these (100 or so) tests are skipped when running against Sqlite.

So when making changes to anything involved with search or closely related to the database, it is wise to test against PostgreSQL.

To test against PosgreSQL:
       1. Edit your local development.ini to specify a PostgreSQL database with the `sqlalchemy.url` parameter.
       2. Tell nose to use test-core.ini (which imports settings from development.ini)


     nosetests ckan/tests --ckan --with-pylons=test-core.ini
The test suite takes a long time to run against standard PostgreSQL (approx. 15 minutes, or close to an hour on Ubuntu/10.04 Lucid).

This can be improved to between 5 and 15 minutes by running PostgreSQL in memory and turning off durability, as described at <>. 

.. _migrationtesting:

If your changes require a model change, you'll need to write a migration script. To ensure this is tested as well, you should instead run the tests this way::

     nosetests ckan/tests --ckan --ckan-migrate --with-pylons=test-core.ini
By default, tests are run using the model defined in ckan/model, but by using the ``--ckan-migrate`` option the tests will run using a database that has been created using the migration scripts, which is the way the database is created and upgraded in production. These tests are the most thorough and will take around 20 minutes.

.. caution ::

    Ordinarily, you should set ``development.ini`` to specify a PostgreSQL database
    so these also get used when running ``test-core.ini``, since ``test-core.ini``
    inherits from ``development.ini``. If you were to change the ``sqlalchemy.url``
    option in your ``development.ini`` file to use SQLite, the command above would
    actually test SQLite rather than PostgreSQL so always check the setting in
    ``development.ini`` to ensure you are running the full tests.

.. note ::

   A common error when wanting to run tests against a particular database is to change the sqlalchemy.url in test.ini or test-core.ini. The problem is that these are versioned files and people have checked in these by mistake, creating problems for all other developers and the buildbot. This is easily avoided by only changing the sqlalchemy.url in your local development.ini and testing --with-pylons=test-core.ini.

Testing extensions

CKAN extensions ordinarily have their own test.ini that refers to the ckan test.ini, so you can run them in exactly the same way. For example::

    cd ckanext-dgu
    nosetests ckanext/dgu/tests --ckan
    nosetests ckanext/dgu/tests --ckan --with-pylons=test-core.ini


CKAN is an open source project and contributions are welcome! 

There are a number of stakeholders in the direction of the project, so we discuss large changes and new features on the ckan-discuss list:

New developers should aquaint themselves with the documentation (see below). Proposed changes should be made on a personal CKAN fork (on BitBucket for example). Request merging with the mainline via the ckan-discuss list.

We have policies for check-ins that ensure the build doesn't break etc. on which should be followed unless someone builds concensus to change it.


The home page for the CKAN project is:

This README file is part of the Developer Documentation, viewable at: and stored in the CKAN
repo at ``ckan/doc``. 

The Developer Docs are built using `Sphinx <>`_:

      python build_sphinx

(An admin might upload the resulting html to by doing: `easy_install sphinx-pypi-upload` and `python upload_sphinx`)

(The docs are also uploaded via dav to backwards compatability).


  * Rufus Pollock <rufus [at] rufuspollock [dot] org>
  * David Read
  * John Bywater
  * Nick Stenning (css and js)

Also especial thanks to the following projects without whom this would not have
been possible:

  * CKAN logo: "angry hamster" and
  * for silk icons <>
  * Pylons: <>
  * Python: <>

Copying and License

This material is copyright (c) 2006-2011 Open Knowledge Foundation.

It is open and licensed under the GNU Affero General Public License (AGPL) v3.0
whose full text may be found at:


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