psiturk-docker: a docker-compose configuration file to run psiturk with MySQL support.

The docker-compose file runs a standard nginx container, a standard MySQL container, and an ad-hoc psiturk container. It links them all up, so that the nginx container serves all the files it can to the participant of the experiment (delegating what it cannot serve to the Gunicorn server run by psiturk inside the psiturk container) and so that psiturk can record data to the MySQL server container.

DISCLAIMER: this is very experimental, it can be improved (see known issues below), but for the moment it works for me (at least testing it). Feel free to play with it (and maybe submit PRs so we all benefit from it? ;) )

HOW TO

First, make sure that you change config.txt as necessary. Importantly, you'll need to set adserver_revproxy_host to either the static IP address of the machine that your experiment is deployed on or a fully qualified domain name (without the protocol) that resolves to that IP address. You'll also need to set adserver_revproxy_port to 80. While psiturk normally runs on port 22362, nginx is a reverse proxy that sits in front of psiturk since it does a better job of handling traffic and serving static files, and nginx runs on port 80. It delegates everything else to psiturk, running on port 22362.

Important: If you're only just testing things on a local computer (i.e., a computer that is not the deployment computer with a static IP address), you should leave the adserver_revproxy_host value set to the loopback IP address of 127.0.0.1, which is just another way of pointing to the computer that you're currently using. This will allow you to succesfully test and debug the experiment without having to deploy it on the computer with the static IP address. However, when you do deploy the experiment, make sure that you change adserver_revproxy_host to either the static IP address of the deployment machine or a fully qualified domain name (without the protocol) that resolves to that IP address.

Next, install docker and docker-compose. Then run

docker-compose up -d

This should download the relevant images, build the psiturk image, run the containers, and link them. By default they are launched in "daemon" mode (-d).

Then, you need to log in into the psiturk container to use the psiturk shell:

docker attach psiturkdocker_psiturk_1

or change psiturkdocker_psiturk_1 with whatever name shows up for the psiturk container. After that command, you should be logged into the container. To test that everything works, try

cd psiturk-example psiturk

this should launch the psiturk shell. Then cross your fingers and run

server on
debug -p

if your server is visible in the network, copying and pasting the URL on the browser should let you try the experiment.

Note: to detach from the container do not type exit; this will kill the container (although it might restart automatically, it's not nice). Instead, press the sequence ctrl+p ctrl+q to detach.

Data and experiments

By default docker-compose.yml maps ./exp in the host to /psiturk in the psiturk container. (This folder is also mapped to /var/www/psiturk-example in the nginx container, but it is mapped as read only inside of that container; this is so nginx can serve the static files from the experiment, delegating the rest to the psiturk container.) This means that you can put any experiment directory into ./exp, then cd into /psiturk from within the psiturk container, and run the psiturk shell.

The global psiturk configuration file is in ./exp/.psiturkconfig, and the env variable is set to point there inside the container.

Also, the mysql database is saved under ./data/db, and the user and password can be changed by changing the environment variables in docker-compose.yml (remember to change the database_url in the config.txt of the example if you do change it).

Accessing the database through adminer

The docker-compose.yml installs adminer as a service, which allows you to check the database through webpage. You should be able to open the browser and visit localhost:8080 to see the page. Insert the username and password, and you can check when new subjects's data is recorded.

Known issues

• if you run server log from the psiturk shell, it crashes miserably because psiturk wants xterm installed, but we're not installing it. If you do want to see the log, you can always log in the container and cat or tail the server.log file.