Comprehensive Knowledge Archive Network (CKAN) Software.
See :mod:`ckan.__long_description__` for more information.
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: http://buildbot.okfn.org/waterfall
Ensure these packages are installed:
Python interpreter v2.5 - v2.7 and dev headers
XML library development files
XSLT library development files
Python virtual environments
Command line tool for downloading from the web
Tools for building source code
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 sudo apt-get install python-dev python-psycopg2 python-virtualenv
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 --no-site-packages pyenv
If you don't have a python-virtualenv package in your distribution you can get a virtualenv.py script from within the virtualenv source distribution and then run python virtualenv.py pyenv instead.
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 so:
When your shell is activated you will see the prompt change to something like this:
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.
Install CKAN code and required Python packages into the new environment
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:
The pip command will now be available in your virtual environment.
Next you'll need a requirements file. For the latest version run:
Or for the 'metastable' branch (used for most server installs):
Install all the dependencies listed in the requirements file by running the command below in your activated shell (adjusting the filename as necessary for the version you are using):
pip install -r pip-requirements.txt
This will take a long time. Particularly the install of the lxml package.
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.
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
- 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)
Advanced users: If you are using CKAN's fab file capability you currently need to create your config file as pyenv/ckan.net.ini 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/ckan.net.ini, 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.
- 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.
- 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
- 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
Point your web browser at: http://127.0.0.1:5000/
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/.
Make sure you've created a config file: pyenv/ckan/development.ini
Ensure you have activated the environment:
Now start the tests:
cd pyenv/src/ckan nosetests ckan/tests --ckan
By default, the test run is 'quick and dirty' - only good enough as a check before commit coding. Instead of using PostgreSQL the tests use an in-memory Sqlite database, which causes two problems:
- In production you have to PostgreSQL, so any subtleties of this are missed
- The search system relies on PostgreSQL, so these (50 or so) tests are skipped.
So when working on search, or doing changes closely related to the database, it is wise to test against PostgreSQL - see the next section on Configuring Tests.
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.
To use a PostgreSQL database, specify it in your development.ini in the value for sqlalchemy.url and then tell nose to use the test-core.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 <http://www.postgresql.org/docs/9.0/static/non-durability.html>.
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: http://lists.okfn.org/mailman/listinfo/ckan-discuss
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 http://ckan.org/#ProjectProcessesandPolicies which should be followed unless someone builds concensus to change it.
The home page for the CKAN project is: http://ckan.org
This README file is part of the Developer Documentation, viewable at: http://packages.python.org/ckan/ and stored in the CKAN repo at ckan/doc.
The Developer Docs are built using Sphinx:
python setup.py build_sphinx
- 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:
Copying and License
This material is copyright (c) 2006-2010 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: