# Overview

## Introduction

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: http://buildbot.okfn.org/waterfall

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

libxml2-dev

XML library development files

libxslt-dev

XSLT library development files

python-virtualenv

Python virtual environments

wget

build-essential

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

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 --no-site-packages pyenv

Tip

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.

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 so:

. 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

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

The pip command will now be available in your virtual environment.

Next you'll need a requirements file. For the latest version run:

wget http://knowledgeforge.net/ckan/hg/raw-file/default/pip-requirements.txt

Or for the 'metastable' branch (used for most server installs):

wget http://knowledgeforge.net/ckan/hg/raw-file/default/pip-requirements-metastable.txt

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.

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 Postgres 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
1. 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 = postgres://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/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.

1. 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.

1. 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
1. 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

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/.

## Test

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

Ensure you have activated the environment:

. pyenv/bin/activate

Now start the starts:

cd pyenv/src/ckan
nosetests ckan/tests

Caution!

There currently appears to be a bug on fresh installs of Ubuntu 10.04 which means the tests take well over an hour to run. This is a known issue which doesn't affect other versions of Ubuntu or earlier versions which were then upgraded to 10.04.

## Development

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) and proposed patches emailed to ckan-discuss. Once they are comfortable they should request write-access to the repo.

We have policies for check-ins that ensure the build doesn't break etc. on https://knowledgeforge.net/ckan/trac#ProjectProcessesandPolicies which should be followed unless someone builds concensus to change it.

## Documentation

The home page for the CKAN project is: http://knowledgeforge.net/ckan

This README file is part of the Developer Documentation, viewable at: http://knowledgeforge.net/ckan/doc/ckan/index.html and stored in the CKAN repo at ckan/doc.

The Developer Docs are built using Sphinx:

python setup.py build_sphinx

The docs are uploaded to packages.python.org/ckan/ and also (via dav) to http://knowledgeforge.net/ckan/doc/ckan/ (http://knowledgeforge.net/ location is for backwards compatability).

## Contributors

• Rufus Pollock <rufus [at] rufuspollock [dot] org>