admin-backend

This is the backend of the admin interface, used internally @Vochabular for the creation, translation, reviewing and publishing of content.

Introduction

The backend consists of two API applications that are connected to Postgres:

A python Django Application for model classes and business logic

• Mainly used for central business logic such as presigning S3 uploads
• Has Model classes (Code first) definitions to automatically create necessary db migrations
• Uses Graphene to serve a GraphQL API endpoint
• Uses PyJWT for JWT authentication

Hasura GraphQL engine

• A stateless service running on top of postgres
• Automatically provides a GraphQL schema based on the underlaying Postgres DB
• Used for boring CRUD operations and so called subscriptions (live queries via websockets)
• Used for the ACL of CRUD operations
• Consumes the Django GraphQL schema and merges into one to serve the clients a single schema

How to install

• Install python3 and virtualenv
• Create a virtualenv in the checkout: virtualenv -p python3 .venv
• Activate the virtualenv source .venv/bin/activate && pip install pip-tools
  • Windows: cd .venv/Scripts and activate, then cd ../..
• Install dependencies with pip pip install -r requirements.txt

Change dependencies

We use pip-tools for dependency management. To add a new package, add it to requirements.in and run pip-compile, followed by pip-sync. To upgrade all dependencies, run pip-compile --upgrade and pip-sync.

Setup application locally

• Run local postgres: docker run -d -p 5432:5432 --name postgres -e POSTGRES_HOST_AUTH_METHOD=trust postgres
• Run migrations python vochabular/manage.py migrate
• Run server python vochabular/manage.py runserver
• Create admin user python vochabular/manage.py createsuperuser

Run application in docker

• Install docker and docker-compose
• Build or download and run images docker-compose up -d
• Make sure to run the Django migrations to setup the DB: docker exec -it vocha_admin_backend python manage.py migrate
• Make sure to create the super user: docker exec -it vocha_admin_backend python manage.py createsuperuser

Sync staging database with local psql database

With heroku pg:pulland heroku pg:push you either pull the postgresql database from heroku to your local machine or push your local database to heroku:

heroku pg:pull DATABASE vochabular --app vochabular-admin

This command creates a new local database named vochabular and then pulls data from the database at DATABASE from the app vochabular-admin. To prevent accidental data overwrites and loss, the local database must not already exist. You will be prompted to drop an already existing local database before proceeding.

If providing a Postgres user or password for your local DB is necessary, use the appropriate environment variables like so:

PGUSER=postgres PGPASSWORD=password heroku pg:pull DATABASE vochabular --app vochabular-admin

pg:push pushes data from a local database into a remote Heroku Postgres database. The command looks like this:

heroku pg:push mylocaldb DATABASE --app vochabular-admin

This command takes the local database mylocaldb and pushes it to the database at DATABASE on the app vochabular-admin. To prevent accidental data overwrites and loss, the remote database must be empty. You will be prompted to pg:reset a remote database that is not empty.

Usage of the PGUSER and PGPASSWORD for your local database is also supported for pg:push, just like for the pg:pull command.

Sample GraphQL Queries

query {
  chapters {
    titleDE,
    text
  }
}

mutation {
  createChapter(input: {chapterData: {titleCH: "title CH", titleDE: "title DE", text: "asdf"}}) {
    chapter{
      titleCH,
      text
    }
  }
}