How to manage Docker containers

Update the code that is running the web app

The code that runs within the web app is not included in the “web” container. The code is on the host machine in the root of the git repo. If you cloned from github without specifying a new directory name this directory will be GleamXGPMonitoring. Any changes that you make to the code within this repository will visible to the web service running the app. However, depending on how you are running the app, the changes may not be automatically reflected in the app immediately.

If you are running a development deployment, then you should see a message from docker-compose that looks like this:

web_1  | /home/app/web/<app>/views.py changed, reloading.
web_1  | 2023-11-28 04:24:54,283 INFO /home/app/web/<app>/views.py changed, reloading.
web_1  | Watching for file changes with StatReloader
web_1  | 2023-11-28 04:24:54,878 INFO Watching for file changes with StatReloader
web_1  | Performing system checks...

This tells you that some python code has been changed (views.py in this case), and so the web app will restart itself. Changing static files or templates doesn’t require any reload of the web app so you won’t see the above message.

If you are running a production deployment, then the app will NOT automatically reload or apply changes. In this case you have to restart the web app using docker-compose restart web. If you have made changes to static files or templates then you’ll have to also run docker-compose exec web python manage.py collectstatic --noinput so that the static files are updated.

Restart a stopped or broken instance of the web app

In most cases you’ll just need to restart the container hosting the web app using docker-compose restart web.

If this doesn’t work then you can bring down all the containers and restart them using docker-compose down and docker-compose -f docker-compose{.prod}.yml up (depending on wether you are running the prod or dev version).

Clear the database and start “fresh”

There are two ways to do this.

The friendly way

Run docker-compose exec web python manage.py flush which will delete the data from the tables managed by DJango. This doesn’t undo any migrations, and leaves the db schema in tact. To rebuild from here:

  1. Load default data from fixtures:

    • docker-compose exec web python manage.py loaddata <fixture>.json --app <app>.<table>

  2. Create a super user (admin) account:

    • docker-compose exec web python manage.py createsuperuser --noinput

The not-friendly way

Run docker-compose down -v, which brings down all the containers, all the networks, and deletes the associated volumes. You will loose all data associated with the app: tables, schema, user accounts, static files. To rebuild from here:

  1. Start the web app using docker-compose -f docker-compse{.prod}.yml up (depending on whether you are running id dev/prod)

  2. (in different terminal) Collect the static files using docker-compose exec web python manage.py collectstatic --noinput

  3. Create and run all migrations:

    • docker-compose exec web python manage.py makemigrations

    • docker-compose exec web python manage.py migrate

  4. Load default data from fixtures:

    • docker-compose exec web python manage.py loaddata <fixture>.json --app <app>.<table>

  5. Create a super user (admin) account:

    • docker-compose exec web python manage.py createsuperuser --noinput