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Structure overview

Flask

IRIS uses Flask for the web engine.

Routes and blueprints

Each page and API endpoints (eg /login, /dashboard, /case/assets/list, etc) refers to a route in the IRIS Flask app. They define what the application should do when Flask receives a request on an URI.
To keep structure in the projects, these routes are grouped by Blueprints. The Blueprints reflects the structure shown in the IRIS UI left menu. For instance there is a case and an activities Blueprint.

The Blueprints and thus routes are defined in source > app > blueprints.
All the blueprints are registered in source > app > views.py.

Templates

IRIS uses dynamic page templating when an URI is visited. These Jinja2 templates are filled at runtime with the needed information and then returned to the client.
Each route offering a page (i.e non-API endpoints) thus relies on a template. These are set in a folder named templates in each Blueprint.
For instance, for the dashboard template : source > app > blueprints > dashboard > templates > index.html.

Static contents

Static content is served from a common folder under source > app > static > assets. It contains CSS, JS and images. These can be accessed by pages using "/static/assets/<the-resource>".

SQLAlchemy

For the database management, the application uses SQLAlchemy with a PostgreSQL backend. There is - normally - no need to directly deal with PostgreSQL, everything goes through SQLAlchemy.
It provides a Python overlay which allows to talk to the DB with objects.

Models

Each table of the app is defined by a model. These are defined in source > app > model. When IRIS starts, it looks for the already created tables and creates the missing ones if needed.
If changes are done on a table or field, then a migration is needed. This is explained in Alembic migrations.

Requests

To help structuring the code, we are trying to move the DB code from the routes code. This is partially done and work in progress.
If your route requests the DB, please put the DB code in source > app > datamgmt.

Alembic

To apply schema migration without the need to rebuild the DB, IRIS uses Alembic.
It allows to define migration scheme and IRIS calls it when it starts so users can upgrade without too much hassles.

Hooks, modules and tasks

Modules are handled via tasks thanks to Celery and RabbitMQ. More info here and here.

IRIS startup

When starting-up, IRIS initiates a bunch of DB objects, whether it is started for the first time or just restarted. Objects already created are not recreated, but the missing ones are applied. This ensure a smooth migration between versions.
These are defined in source > app > post_init.py. The scripts also contains the code that runs th DB migration with Alembic.


Last update: 2022-05-25
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