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IO mobile backend

This repository contains the code of the backend used by the mobile applications of the IO project.

Table of content

• IO mobile backend
  • Table of content
  • What is this?
  • Authentication process
    • Token authentication
  • How to run the application
    • Dependencies
    • Installation steps
    • Container description
    • Environment variables
    • Logs
  • API Monitoring
  • Redis Database
    • Data Structure
  • Mobile App compatibility
    • Backend
    • PagoPa
  • How to contribute
    • Dependencies
    • Starting steps
    • Architecture decision records
  • Troubleshooting

What is this?

This is the backend that supports the io-app mobile application.

This project is part of the Italian Digital Citizenship initiative, see the main repository for further information.

Authentication process

The io-app application will authenticate using the APIs exposed by the service Session Manager in IO Auth monorepo.

Once the token is obtained it can be used to call authenticated APIs of this repository.

Token authentication

All API requests sent by the client to the backend must have an Authorization: Bearer header with the value of the token obtained from the SPID authentication process. The token is used to retrieve the User object from the SessionStorage service.

The code that manage this flow are in the src/strategies/bearerSessionTokenStrategy.ts file.

How to run the application

Dependencies

• Docker and Docker Compose

A Linux/macOS environment is required at the moment.

Installation steps

1. clone the project in a folder called io-backend

2. go to the project's folder

3. run scripts/build-tools.sh to build the tools Docker image

4. run scripts/yarn.sh to install backend dependencies

5. run scripts/generate-proxy-api-models.sh to generate the models defined in api_proxy.yaml and api_notifications.yaml

6. run scripts/build.sh to compile the Typescript files

7. run scripts/generate-test-certs.sh to create certificates needed to start the HTTPS server in DEV mode

8. edit your /etc/hosts file by adding:

   127.0.0.1    io-backend
   

9. copy .env.example to .env and fill the variables with your values

10. run docker compose --env-file .env up -d to start the containers

11. point your browser to https://io-backend/info to check that the server is started

If you are using Docker with a Docker Machine replace localhost with the IP of the Docker Machine (More details here).

Container description

• backend: the backend Node application that serves the web and mobile applications

Nginx is reachable at https://io-backend \

Environment variables

Those are all Environment variables needed by the application:

Notes:

• FETCH_KEEPALIVE_ENABLED should be enabled when deploying on Azure App Service to avoid SNAT Exhaustion
• FETCH_KEEPALIVE_MAX_SOCKETS depends on the number of node processes running on the VM, see this article and this issue
• FETCH_KEEPALIVE_SOCKET_ACTIVE_TTL should be set at around 100 seconds when deploying on Azure, see this comment

If you are trying to run the docker images on your local environment (through the docker-compose) you must set the following variables:

• NOTIFICATIONS_STORAGE_CONNECTION_STRING
• PUSH_NOTIFICATIONS_STORAGE_CONNECTION_STRING
• LOLLIPOP_REVOKE_STORAGE_CONNECTION_STRING With this connection string as value:
• DefaultEndpointsProtocol=http;AccountName=devstoreaccount1;AccountKey=Eby8vdM02xNOcqFlqUwJPLlmEtlCDXJ1OUzFT50uSRZ6IFsuFq2UVErCz4I6tq/K1SZFPTOtr/KBHBeksoGMGw==;BlobEndpoint=http://127.0.0.1:20003/devstoreaccount1;QueueEndpoint=http://127.0.0.1:20004/devstoreaccount1;TableEndpoint=http://127.0.0.1:20005/devstoreaccount1;

The connection string has a default value needed to connect to Azurite, a local emulator used to provide a free local environment for testing an Azure Blob, Queue Storage, and Table Storage application. As for docker-compose instructions, the Azurite docker image runs the Blob service on port 20003, the Queue service on port 20004 and the Table service on port 20005. If Azurite is executed on different address or ports, the connection string must be changed according to the service.

You must also set the following variables:

• REDIS_URL
• REDIS_PORT
• REDIS_PASSWORD

With the same values defined in the docker-compose.yml file.

Logs

Application logs are saved into the logs folder.

API Monitoring

Is possible link the API to AppInsignts service by setting the ENV variable APPINSIGHTS_INSTRUMENTATIONKEY. Stats of API CPU and RAM usage, API call execution time, success or failure of API calls are collected. Realtime data collection is enabled.

Redis Database

Data Structure

Redis Database stores data required only by application side functionalities. Below a table with an example of data for an hypothetical user with fiscal code MRARSS80A01H501T and with session token HexToken.

Mobile App compatibility

Backend

To handle Backend compatibility with several Mobile App versions, the oldest mobile app version supported by the backend is stored into the property min_app_version inside the package.json. This value is provided to the app through the /info API. If the mobile app version is lower an upgrade is required.

PagoPa

To handle the mobile app compatibility with the latest implementation of PagoPA APIs, the backend exposes through the /info API a property called min_app_version_pagopa defined into package.json file. If the mobile app version is lower of this value, all the functions that require PagoPa are disabled to avoid compatibility issues.

How to contribute

Dependencies

• nodenv
• YARN
• Docker (optional)

A Linux/macOS environment is required at the moment.

Starting steps

• use nodenv to run the correct version of Nodejs as specified in app/.node-version
• run Jest tests directly or with scripts/test.sh

In general follow the Node Best Practices.

Architecture decision records

In a world of evolutionary architecture, it's important to record certain design decisions for the benefit of future team members as well as for external oversight. Architecture Decision Records is a technique for capturing important architectural decisions along with their context and consequences. We store these details in source control, along with code, as then they can provide a record that remains in sync with the code itself.

We use ADRs to track architectural decisions of this initiative.

This repository is configured for Nat Pryce's adr-tools.

Here's the decisions we taken so far:

Troubleshooting

I installed on my mac but seems that https://io-backend is not working (ping io-backend return a host error)

Check out /etc/hosts Remember that in some cases you need to use your docker-machine ip (get it from >docker-machine ip) instead of localhost.

I followed all the steps but when i go to https://io-backend it shows me the same as https://io-backend:8080

This problem seems to be dependent on how Docker for Mac (doesn't) manage well the /etc/hosts file. If you install Docker Toolbox it works fine (and can coexist) (Read more at https://medium.com/@itseranga/set-hosts-in-docker-for-mac-2029276fd448)