SAEON Dash Applications

A repository of Dash applications developed by the SAEON uLwazi Node's Data Science Team.

Development

Initial setup

First, browse to the SAEON Dash_applications repository, and click the Fork button. This will create a copy of the repository under your own GitHub account.

Then, clone the fork to your local computer:

git clone https://github.com/<your-github-username>/Dash_applications.git

Switch to the Dash_applications directory:

cd Dash_applications/

Create a Python virtual environment:

python -m venv .venv

Activate the virtual environment:

On Windows

.venv\Scripts\activate

On Linux and mac

source .venv/bin/activate

Install Dash and other packages to the Virtual Environment

pip install -U pip setuptools pip-tools
pip-sync

Now you can open the Dash_applications folder as a project in the PyCharm IDE.

General notes

• @app.callback outputs must have a unique name for each app

Deployment

The Dash Server is a linux server located at 192.168.117.49

Ask Sephy to create a username and password for you on that server and you will be able to SSH onto the server.

After Accessing the server, switch to the root user by typing sudo -s. Then, cd to the cd /srv/Dash_applications directory and run the following commands to update the deployed Dash apps:

git pull
docker-compose build
docker-compose up -d

Admin

Managing dependencies

The requirements.txt file defines exactly which packages - and which versions of those packages - must be installed to the Python virtual environment, for both local development and server deployments.

requirements.txt is compiled from requirements.in using the pip-compile command.

To add a Python package - e.g. pandas - that is referenced by any module in this repository, first add it to requirements.in file. Then, run:

pip-compile

To upgrade existing referenced packages or their dependencies, run:

pip-compile --upgrade

Your local virtual environment can then be updated with any new or updated packages using the following command:

pip-sync

Note that, after upgrading any packages or their dependencies, it's a good idea to test that everything works as expected, before committing the updated requirements.txt to source control.