Getting Started

The example details how to

  1. install a local instance of Alyx

  2. initialize it with the fixtures

  3. register some local data to it

  4. using the ONE-api, load the registered data

Requirements: this tutorial works on Linux as it relies on installing postgres and Django.

The script sets up postgres (it creates the database and postgres user), it creates the settings files

  • alyx/alyx/

  • alyx/alyx/

  • alyx/alyx/

Note that the postgres username and password are distinct from Alyx (Django) users and password. There is only one postgres user that is only used locally for maintenance task or by Django.

Install a local instance of Alyx

Ubuntu or Debian based Linux

Go to the directory of your choice (for example: /var/www/alyx-local) and follow the installation guide

Install required packages

# install required packages 
sudo apt-get install python3-pip python3-dev libpq-dev postgresql postgresql-contrib virtualenv

Create log folder and folder for storing uploaded content.

sudo mkdir /var/log/alyx
sudo mkdir uploaded
sudo chmod 775 -fR uploaded
sudo chown www-data:www-data -fR uploaded

Clone the repository and install the environment

git clone 
virtualenv alyxvenv --python=python3
source ./alyxvenv/bin/activate
pip install -r requirements.txt

Install Alyx, check installation. Then load init fixtures in the database and launch the server.

    $ Enter a database name [alyxlocal]:
    $ Enter a postgres username [alyxlocaluser]:
    $ Enter a postgres password:
python alyx/ check

cd alyx

python runserver

NB: the password above is the postgres database user password. It is used by Django only to connect to the database, and is distinct from any user password on admin website.

You can then visit http://localhost:8000/admin, connect as admin:admin (ie. username admin and password admin) and update your admin interface password.


  • Install Python 3 (using the official installer, or conda). Make sure pip is installed.

  • Install

  • Open a Terminal.

  • Type git, press Enter, and follow the instructions to install git.

  • Type sudo touch /var/log/alyx.log; sudo chmod 776 /var/log/alyx.log;

  • Type sudo mkdir -p /etc/paths.d && echo /Applications/ | sudo tee /etc/paths.d/postgresapp

  • Open, and press initialize/start to start the server.

  • Close the terminal, open a new one, and go to a directory where you’ll download alyx into.

  • Type git clone

  • cd alyx

  • Type pip install -r requirements.txt

  • Type pip uninstall python-magic

  • Type pip install python-magic-bin

  • Type python, and follow the instructions.

  • If everything went well you should see no error message and the message Alyx setup successful <3.

  • Type python alyx/ check. You should see the message System check identified no issues (0 silenced).

  • To reinitialize your local database, type alyx/ reset_db --noinput

  • To clone an existing alyx database from a backup, get an alyx_full.sql.gz in your alyx folder, and type gunzip -f alyx_full.sql.gz

  • Then type psql -h localhost -U labdbuser -d labdb -f alyx_full.sql — this command might take a few minutes with large backups

  • Type python migrate

  • To run the development server, type python alyx/ runserver

  • Go to http://localhost:8000/admin/

Interaction with the database

There are 3 main ways to interact with the database, listed below:




Django Shell

server only

admin only

This hits the database directly. It is a very powerful way to do maintenance at scale, with the risks associated. Run the ./ shell Django command to access the Ipython shell.

Admin Web Page

web client


Manual way to input data in the database. This is privilegied for users needing to add/amend/correct metadata related to subjects. For the local database, this is accessible here: http://localhost:8000/admin.


web client


Programmatical way to input data, typically by acquisition software using a dedicated Alyx client ONE (Python) or ALyx-matlab (Matlab).

Create an experiment, register data and access it locally

Here we’ll create the minimal set of fixtures to register some data to an experimental session.

  1. create project

  2. create repository

  3. assign repository to lab

  4. create a subject

If your server is not already running, from the root of the cloned repository:

source ./alyxvenv/bin/activate
python alyx/ runserver

Then in another terminal:

source ./alyxvenv/bin/activate
pip install ONE-api

At the python prompt, this will create the set of init fixtures to register and recover data

from pathlib import Path
from one.api import ONE

# create the local folder on the machine
one = ONE(base_url='http://localhost:8000')
ROOT_EXPERIMENTAL_FOLDER = Path.home().joinpath('alyx_local_data')
ROOT_EXPERIMENTAL_FOLDER.mkdir(parents=True, exist_ok=True)

# create the project
project ='projects', 'create', data=dict(name='main', users=['admin']))
# create the repository with name 'local' (NB: an URL is needed here, even if it is rubbish as below)
repo ='data-repository', 'create', data=dict(name='local', data_url=''))
# assign the repository to 'defaultlab''labs', 'partial_update', id='defaultlab', data=dict(repositories=['local']))
# create a subject'subjects', 'create', data=dict(nickname='Algernon', lab='defaultlab', project='main', sex='M'))

Create a session using the REST endpoint and ONE-api

Activate your environment, install the ONE-api, and run a Python shell. From the root of the repository:

source ./alyxvenv/bin/activate
pip install ONE-api

Then in Python

# instantiate the one client
from pathlib import Path
import pandas as pd
import numpy as np
from one.api import ONE
from datetime import datetime
one = ONE(base_url='http://localhost:8000')
ROOT_EXPERIMENTAL_FOLDER = Path.home().joinpath('alyx_local_data')

# create a session
session_dict = dict(subject='Algernon', number=1, lab='defaultlab', task_protocol='test registration',
                    project="main", start_time=str(, users=['admin'])
session ='sessions', 'create', data=session_dict)
eid = session['url'][-36:]  # this is the experimental id that will be used to retrieve the data later

# create a trials table in the relative folder defaultlab/Subjects/Algernon/yyyy-mm-dd/001
session_path = ROOT_EXPERIMENTAL_FOLDER.joinpath(
    session['lab'], 'Subjects', session['subject'], session['start_time'][:10], str(session['number']).zfill(3))
alf_path = session_path.joinpath('alf') 
alf_path.mkdir(parents=True, exist_ok=True)
ntrials = 400
trials = pd.DataFrame({'choice': np.random.randn(400) > 0.5, 'value': np.random.randn(400)})

# register the dataset
r = {'created_by': 'admin',
     'path': session_path.relative_to((session_path.parents[2])).as_posix(),
     'filenames': ['alf/trials.table.pqt'],
     'name': 'local'  # this is the repository name
response ='register-file', 'create', data=r, no_cache=True)

Recover the data by querying the session

from pathlib import Path
from one.api import ONE
one = ONE(base_url='http://localhost:8000')
ROOT_EXPERIMENTAL_FOLDER = Path.home().joinpath('alyx_local_data')
session ='sessions', 'list', subject='Algernon')[-1]
eid = session['id']

# from the client side, provided with only the eids we reconstruct the full dataset paths
local_path = ROOT_EXPERIMENTAL_FOLDER.joinpath(*one.eid2path(eid).parts[-5:])
local_files = [local_path.joinpath(dset) for dset in one.list_datasets(eid)]

We went straight to the point here, which was to create a session and register data, to go further consult the One documentation, in the section “Using one in Alyx”.