Server-side code for Circles mobile app.

General info/features

• Flask app that runs on Google App Engine // GCP.
• Exposes a REST API (GET, POST, PUT, DELETE endpoints) for the client-side application.
• Database is a Neo4j (graph db) instance running on Google Compute Engine.
• Authentication/User-management with Firebase.
• Push notifications with Firebase Cloud Messaging.
• Credentials for GCE instance & FCM stored and queried through Cloud Datastore.

Development/Build architecture

We have both a Development and Production build pipeline. Prod reflects code on master while Dev reflects the latest PR to master:

1. Push changes to new branch
2. Create a pull request to master for your changes
3. Cloud Build (under circles-dev GCP project) is triggered; build must succeed to merge PR
4. One reviewer must approve the PR
5. PR may be merged to master
6. Cloud Build (under circles GCP project) is triggered; app deployed to prod

(Graph) Data Model

There are three nodes or "Objects":

1. Person
2. Circles
3. Events

Relationships exist as follows (note that edges can be queried bidirectionally in Neo4j):
(Person) <- :KNOWS -> (Person)
(Person) :IS_MEMBER -> (Circle)
(Person) :INVITED_TO -> (Event)
(Circle) :SCHEDULED -> (Event)