Linux Server¶

Note

If you are just testing your app locally, you can use otree runserver, which is simpler than the below steps.

We typically recommend oTree users to deploy to Heroku (see instructions here), because that is the simplest for people who are not experienced with web server administration.

However, you may prefer to run oTree on your own server. Reasons may include:

You will be launching your experiment in a setting where internet connectivity is lacking
You do not want your server to be accessed from the internet
You want full control over how your server is configured
You want better performance (local servers have less latency)

The below instructions are for Ubuntu 16.04.

Note

There is now a Docker-based oTree installation, which may be easier than the below steps.

Another alternative is to use the VirtualBox Fedora oTree server created by Gregory Huber at Yale. You can download it here, or follow the below instructions to configure your own server.

Install apt-get packages¶

Run:

sudo apt-get install python3-pip python3-dev libpq-dev postgresql postgresql-contrib redis-server git

Create a virtualenv¶

It’s a best practice to use a virtualenv:

python3 -m venv venv_otree

Then in your .bashrc or .bash_profile, add this command so your venv is activated each time you start your shell:

source ~/path/to/your/venv_otree/bin/activate

Database (Postgres)¶

oTree’s default database is SQLite, which is fine for local development, but insufficient for production. We recommend PostgreSQL, although you can also use MySQL, MariaDB, or any other database supported by Django.

Change users to the postgres user, so that you can execute some commands:

sudo su - postgres

Then start the Postgres shell:

psql

Once you’re in the shell, create a database and user:

CREATE DATABASE django_db;
CREATE USER otree_user WITH PASSWORD 'mypassword';
GRANT ALL PRIVILEGES ON DATABASE django_db TO otree_user;

Exit the SQL prompt:

\q

Exit out of the postgres user and return to your regular command prompt:

exit

Now you should tell oTree to use Postgres instead of SQLite. The default database configuration in settings.py is:

DATABASES = {
    'default': dj_database_url.config(
        default='sqlite:///' + os.path.join(BASE_DIR, 'db.sqlite3')
    )
}

However, instead of modifying the above line directly, it’s better to set the DATABASE_URL environment variable on your server. Setting the database through an environment variable allows you to continue to use SQLite on your development machine, while using Postgres on your production server.

If you used the values in the example above (username otree_user, password mypassword and database django_db), you would add this line to your .bash_profile or .bashrc:

export DATABASE_URL=postgres://otree_user:mypassword@localhost/django_db

Then restart your shell, and confirm the env var is set, with echo $DATABASE_URL. Once DATABASE_URL is defined, oTree will use it instead of the default SQLite. (This is done via dj_database_url.)

Then run:

pip3 install psycopg2
otree resetdb

Install Redis¶

If you installed redis-server through apt-get as instructed earlier, Redis should be running on port 6379. You can test with redis-cli ping, which should output PONG.

If there was an installation problem, you can try installing Redis from an alternate source, e.g. here.

Set up Git¶

If your code is on your personal computer and you are trying to push it to this web server, you can use Git.

On the server¶

On the server, create 2 directories – one to store your project files, and another to serve as the Git remote:

mkdir oTree
mkdir oTree.git

Create a git repo in oTree.git:

cd oTree.git
git init --bare

Using a text editor such as nano, emacs, vim, add the following to oTree.git/hooks/post-receive:

emacs hooks/post-receive

Then add the following lines to that file:

#!/bin/sh
GIT_WORK_TREE=/path/to/your/oTree
export GIT_WORK_TREE
git checkout -f

This means that every time someone pushes to oTree.git, the code will be checked out to the other directory oTree. (This technique is further described here.)

Make sure that post-receive is executable:

chmod +x hooks/post-receive

On your PC¶

On your PC, open your shell, and make sure you have committed any changes as follows:

pip3 freeze > requirements_base.txt
git add .
git commit -am '[commit message]'

(If you get the message fatal: Not a git repository (or any of the parent directories): .git then you first need to initialize the git repo.)

Then add your server as a remote:

git remote add my-server my-username@XXX.XXX.XXX.XXX:oTree.git

Substitute these values in the above command: - my-username is the Linux login username - XXX.XXX.XXX.XXX is the server’s IP address or hostname - oTree.git is the folder with the empty git repo, - my-server is the name you choose to call your remote (e.g. when doing git push).

Then push to this remote:

$ git push my-server master

Reset the database on the server¶

On the server, cd to the oTree directory. Do ls to verify that your files were indeed transferred when you did git push in the previous step. install the requirements and reset the database:

pip3 install -r requirements.txt
otree resetdb

Running the server¶

If you are just testing your app locally, you can use the usual runserver command.

However, when you want to use oTree in production, you need to run the production server, which can handle more traffic.

Note: oTree does not run with typical Django WSGI servers like gunicorn. It needs the special daphne server, which supports WebSockets.

Testing the production server¶

From your project folder, run:

otree runprodserver --port=80

This will run Django’s collectstatic to collect your static files, then start the server. If it works, you will be able to navigate in your browser to your server’s IP address or hostname. You don’t need to append :80 to the URL, because that is the default HTTP port.

Note: unlike runserver, runprodserver does not restart automatically when your files are changed.

Process control system¶

Once the server is working as described above, it’s a good practice to use a process control system like Supervisord or Circus. This will restart your processes in case they crash, keep it running if you log out, etc.

Supervisor¶

Install supervisor:

sudo apt-get install supervisor

If you install supervisor through apt-get, it will be installed as a service, and will therefore automatically start when your server boots. (You can also install supervisor with pip, but unlike oTree it’s only compatible with Python 2, so you should install it into your system’s Python 2 installation, rather than your Python 3 virtualenv.)

In the supervisor config dir /etc/supervisor/conf.d/, create a file otree.conf with the following content:

[program:otree]
command=/home/my_username/venv_otree/bin/otree runprodserver --port=80
directory=/home/my_username/oTree
stdout_logfile=/home/my_username/otree-supervisor.log
stderr_logfile=/home/my_username/otree-supervisor-errors.log
autostart=true
autorestart=true
environment=
    PATH="/home/my_username/venv_otree/bin/:%(ENV_PATH)s",
    DATABASE_URL="postgres://otree_user:otree@localhost/django_db",
    OTREE_ADMIN_PASSWORD="my_password", # password for oTree web admin
    OTREE_PRODUCTION="0", # can set to 1
    OTREE_AUTH_LEVEL="", # can set to STUDY or DEMO

directory should be the dir containing your project (i.e. with settings.py).

DATABASE_URL should match what you set earlier. That is, you need to set DATABASE_URL in 2 places:

in your .bashrc, so that otree resetdb works
in your otree.conf so that otree runprodserver works.

Because normally supervisor executes otree runprodserver as the root user, but you execute otree resetdb as regular (non-root) user. So the env var needs to be set in both environments.

To start or restart the server (e.g. after making changes), do:

sudo service supervisor restart

If this doesn’t start the server, check the stdout_logfile you defined above, or /var/log/supervisor/supervisord.log.

Alternative: Circus¶

An alternative to Supervisor is Circus.

To install:

sudo apt-get install libzmq-dev libevent-dev
pip3 install circus circus-web

Create a circus.ini in your project folder, with the following content (can do this locally and then git push again):

[watcher:webapp]
cmd = otree
args = runprodserver --port=80
use_sockets = True
copy_env = True

Run the following commands:

otree collectstatic
circusd circus.ini

If this is working properly, you can start it as a daemon:

circusd --daemon circus.ini

Apache, Nginx, etc.¶

You can use oTree without Apache or Nginx. oTree comes installed with the Daphne web server, which is launched automatically when you run otree runprodserver.

oTree does not work with WSGI servers like Gunicorn or mod_wsgi. Instead it requires an ASGI server, and currently the main/best one is Daphne. Apache and Nginx do not have ASGI server implementations, so you cannot use Apache or Nginx as your primary web server.

However, you still might want to use Apache/Nginx as a reverse proxy, for the following reasons:

You are trying to optimize serving of static files (though oTree uses Whitenoise, which is already fairly efficient)
You need to host other websites on the same server, and can only use port 80
You need features like SSL or proxy buffering

Apache¶

If you want to run oTree on a subdomain of your host so that you can share port 80 with other sites hosted on the same machine, you can try the below configuration. The below example assumes oTree server is running on port 8000. For HTTPS, change 80 to 443 ws prefix to wss:

<VirtualHost *:80>
        ServerName otree.domain.com
        ProxyRequests Off
        ProxyPreserveHost On
        ProxyPass / http://localhost:8080/
        ProxyPassReverse / http://localhost:8080/

        RewriteEngine On
        RewriteCond %{HTTP:Connection} Upgrade [NC]
        RewriteCond %{HTTP:Upgrade} websocket [NC]
        RewriteRule /(.*) ws://127.0.0.1:8000/$1 [P,L]
</VirtualHost>

Troubleshooting¶

If you get strange behavior, such as random changes each time the page reloads, it might be caused by another oTree instance that didn’t shut down. Try stopping oTree and reload again. Also make sure that you are not sharing the same Postgres or Redis databases between two oTree instances.

Sentry¶

It’s highly recommended to set up Sentry, so that you can monitor errors on the server

Database backups¶

If you are using Postgres, you can export your database to a file called otree.sql with a command like this:

pg_dump -U otree_user -h localhost django_db > otree-$(date +"%Y-%m-%d-%H-%M").sql

(This assumes your database is set up as described above (with username otree_user and database name django_db, and that you are on Unix.)

Bots¶

Before launching a study, it’s advisable to test your apps with bots, especially browser bots. See the section Bots & automated testing.

Modifying an existing database¶

Note

This section is more advanced and is for people who are comfortable with troubleshooting.

If your database already contains data and you want to update the structure without running resetdb (which will delete existing data), you can use Django’s migrations feature. Below is a quick summary; for full info see the Django docs here.

The first step is to run python manage.py makemigrations my_app_name (substituting your app’s name), for each app you are working on. This will create a migrations directory in your app, which you should add to your git repo, commit, and push to your server.

Instead of using otree resetdb on the server, run python manage.py migrate (or otree migrate). If using Heroku, you would do heroku run otree migrate. This will update your database tables.

If you get an error NameError: name 'Currency' is not defined, you need to find the offending file in your app’s migrations folder, and add from otree.api import Currency at the top of the file.

If you make further modifications to your apps, you can run python manage.py makemigrations. You don’t need to specify the app names in this command; migrations will be updated for every app that has a migrations directory. Then commit, push, and run python manage.py migrate again as described above.

More info here

Linux Server¶

Install apt-get packages¶

Create a virtualenv¶

Database (Postgres)¶

Install Redis¶

Set up Git¶

On the server¶

On your PC¶

Reset the database on the server¶

Running the server¶

Testing the production server¶

Process control system¶

Supervisor¶

Alternative: Circus¶

Apache, Nginx, etc.¶

Apache¶

Troubleshooting¶

Sentry¶

Database backups¶

Bots¶

Modifying an existing database¶

Table Of Contents

Related Topics

This Page

Linux Server¶

Install apt-get packages¶

Create a virtualenv¶

Database (Postgres)¶

Install Redis¶

Set up Git¶

On the server¶

On your PC¶

Reset the database on the server¶

Running the server¶

Testing the production server¶

Process control system¶

Supervisor¶

Alternative: Circus¶

Apache, Nginx, etc.¶

Apache¶

Troubleshooting¶

Sentry¶

Database backups¶

Bots¶

Sharing a server with other oTree users¶

Modifying an existing database¶