edx-platform/doc/development.md

Development Tasks

Prerequisites

Ruby

To install all of the libraries needed for our rake commands, run bundle install. This will read the Gemfile and install all of the gems specified there.

Python

Run the following::

pip install -r requirements.txt

Binaries

Install the following:

• Mongodb (http://www.mongodb.org/)

Databases

First start up the mongo daemon. E.g. to start it up in the background using a config file:

mongod --config /usr/local/etc/mongod.conf &

Check out the course data directories that you want to work with into the GITHUB_REPO_ROOT (by default, ../data). Then run the following command:

rake resetdb

Installing

To create your development environment, run the shell script in the root of the repo:

scripts/create-dev-env.sh

Starting development servers

Both the LMS and Studio can be started using the following shortcut tasks

rake lms  # Start the LMS
rake cms  # Start studio
rake lms[cms.dev]  # Start LMS to run alongside Studio
rake lms[cms.dev_preview]  # Start LMS to run alongside Studio in preview mode

Under the hood, this executes django-admin.py runserver --pythonpath=$WORKING_DIRECTORY --settings=lms.envs.dev, which starts a local development server.

Both of these commands take arguments to start the servers in different environments or with additional options:

# Start the LMS using the test configuration, on port 5000
rake lms[test,5000]  # Executes django-admin.py runserver --pythonpath=$WORKING_DIRECTORY --setings=lms.envs.test 5000

N.B. You may have to escape the [ characters, depending on your shell: rake "lms[test,5000]"

To get a full list of available rake tasks, use:

rake -T

Troubleshooting

Reference Error: XModule is not defined (javascript)

This means that the javascript defining an xmodule hasn't loaded correctly. There are a number of different things that could be causing this:

1. See Error: watch EMFILE

Error: watch EMFILE (coffee)

When running a development server, we also start a watcher process alongside to recompile coffeescript and sass as changes are made. On Mac OSX systems, the coffee watcher process takes more file handles than are allowed by default. This will result in EMFILE errors when coffeescript is running, and will prevent javascript from compiling, leading to the error 'XModule is not defined'

To work around this issue, we use Process::setrlimit to set the number of allowed open files. Coffee watches both directories and files, so you will need to set this fairly high (anecdotally, 8000 seems to do the trick on OSX 10.7.5, 10.8.3, and 10.8.4)

Running Tests

See testing.md for instructions on running the test suite.

Content development

If you change course content, while running the LMS in dev mode, it is unnecessary to restart to refresh the modulestore.

Instead, hit /migrate/modules to see a list of all modules loaded, and click on links (eg /migrate/reload/edx4edx) to reload a course.

Gitreload-based workflow

github (or other equivalent git-based repository systems) used for course content can be setup to trigger an automatic reload when changes are pushed. Here is how:

1. Each content directory in mitx_all/data should be a clone of a git repo

2. The user running the mitx gunicorn process should have its ssh key registered with the git repo

3. The list settings.ALLOWED_GITRELOAD_IPS should contain the IP address of the git repo originating the gitreload request. By default, this list is ['207.97.227.253', '50.57.128.197', '108.171.174.178'] (the github IPs). The list can be overridden in the startup file used, eg lms/envs/dev*.py

4. The git post-receive-hook should POST to /gitreload with a JSON payload. This payload should define at least

   { "repository" : { "name" : reload_dir }

   where reload_dir is the directory name of the content to reload (ie mitx_all/data/reload_dir should exist)

   The mitx server will then do "git reset --hard HEAD; git clean -f -d; git pull origin" in that directory. After the pull, it will reload the modulestore for that course.

Note that the gitreload-based workflow is not meant for deployments on AWS (or elsewhere) which use collectstatic, since collectstatic is not run by a gitreload event.

Also, the gitreload feature needs MITX_FEATURES['ENABLE_LMS_MIGRATION'] = True in the django settings.