Nettverksdagen 2.0

We can only see a short distance ahead, but we can see plenty there that needs to be done. – Alan Turing

Prerequisites

• Docker

Project Installation

The project requires minimal setup for the development environment:

git clone https://github.com/Nettverksdagen/Nettverksdagen-2.git
cd Nettverksdagen-2
docker compose up

The webpage should now appear on localhost:8080 and the django REST api browser on localhost:8000.

Mail Setup

Mail setup in development environment

https://ethereal.email can create fake credentials, and the service can show all emails that were attempted sent (without actually sending them). This is also mentioned in postfix/.env.default. To use the service:

• Copy postfix/.env.default to postfix/.env
• Replace values with credentials from our https://ethereal.email

Mail setup in production environment

If you want to be able to actually send emails:

• Copy postfix/.env.default to postfix/.env
• Replace values with credentials from our mail provider (currently Uniweb)

Quick tour of docker and the container setup

What is docker and how does it help us?

Docker is a containerization and virtualization platform that packs individual components of the complete system into small containers that can be easily deployed on different platforms. Each part of the system is run in its own little linux virtual machine with very minimal overhead. With docker compose, setting up a large system with many docker containers can be made relatively painless.

In our case, we have both a single-page vue frontend, a django REST api and a PostgreSQL database. The setup of this 3-part system can through the use of docker be reduced to a single docker compose up command. Deployments can also be simplified tremendously, especially as the system grows, and the development environment can be made to match the production environment much more closely.

The setup

Starting the webpage with docker compose up spins up four docker containers. A Vue js single page web application, a Django REST API that interfaces a PostgreSQL database and a simple file uploading/hosting server for handling image uploads. The flow of communication between these four components are shown in the figure below. We can retrieve a list of the containers when they are running with the ps command:

docker ps

To enter one of the listed containers and have a look around, copy the name of the container in question from the previous output (or let docker autocomplete it for you with tab) and type

docker exec -ti nettverksdagen-2_frontend_1_c27e85b4cd47 bash

replacing nettverksdagen-2_frontend_1_c27e85b4cd47 with the name of your container. This will put you in a familiar bash shell. As you will probably notice, this shell is very limited. It does for example not come with a text-editor out of the box, but you can easily install one with apt-get if necessary. What is more, the fileserver container is based on a scratch image and so it doesn't even have bash. You can however execute single commands with docker exec as above. So for example to list files, run:

docker exec -ti nettverksdagen-2_fileserver_1_c27e85b4cd47 ls

Volumes

Any folders defined under volumes in docker compose.yml will be mirrored into the container. Thus, folders containing the project files, namely

• api/nvdagen
• api/nvdnew
• frontend/src
• frontend/static
• frontend/test

will have any changes made to them reflected in the docker container when when files are saved. The frontend even has hot reloading enabled, which means the webpage doesn't need to be reloaded for changes made in frontend/ to appear in the browser window.

Usage

Django REST: migrations and the database

Changes in the database need to be reflected in a database migration so that the database schema and any previous data can be updated to the new model correctly. The migrations have to be executed inside the docker container for the api, so to begin, we list the running docker containers with docker ps and enter the api container:

docker exec -ti nettverksdagen-2_api_1_137f29309c2e bash

If we then have made changes to the model, we can generate a new migration with

python manage.py makemigrations

and perform migrations with

python manage.py migrate

Note that the api container has python 3 installed as the default python version, so there is no need to run these commands with python3.

The data already in the database can be cleared with

python manage.py flush

(warning: this will destroy all data)

New fixtures are loaded with

python manage.py loaddata fixtures.json

Create superuser for the api

To create a superuser for the api, execute the following command in the api container:

python manage.py createsuperuser

You will then be guided through the process of creating the user.

Install new NPM packages

When installing a new npm package, the frontend container needs to be rebuilt. This can be done with the following command:

docker compose build --no-cache

Restart the file server

docker compose stop fileserver && docker compose up --no-deps -d --build fileserver

Admin user

The dev environment has a default admin user with the following credentials:

Username	Password
admin	1234

Restoring from backups

Backups of the site and it's data should be regularly created. If something goes wrong, one can restore from a backup by calling

./nettverksdagen restore <backup-name>

The backups must be stored in the /opt/backups folder for this to work.

Other random things

Curl examples with authentication

Login

curl -X POST http://127.0.0.1:8000/rest-auth/login/ -d "username=admin&password=1234"

Create a listing

curl -X POST  http://127.0.0.1:8000/api/listing/ -d "name=test&company_name=test company" -H 'Authorization: Token c56ddd032e56280827fdf4c7c2d5ab338c1a1133'