cdp-python-template-prototype

Core Delivery Platform Python Backend Template.

This is work-in-progress. See To Do List

• cdp-python-template-prototype
  • Requirements
    • Python
    • Docker
  • Local development
    • Setup
    • Development
    • Testing
    • Production
  • API endpoints
  • Custom Cloudwatch Metrics
  • Pipelines
    • Dependabot
    • SonarCloud
  • Licence
    • About the licence

Requirements

Python

Please install python >= 3.12 and configure your python virtual environment:

# create the virtual environment
python -m venv .venv

# activate the the virtual environment in the command line
source .venv/bin/activate

# update pip
python -m pip install --upgrade pip 

# install the dependencies
pip install -r requirements-dev.txt

This opinionated template uses the Fast API Python API framework.

This and all other runtime python libraries must reside in requirements.txt

Other non-runtime dependencies used for dev & test must reside in requirements-dev.txt

Docker

This repository uses Docker throughput its lifecycle i.e. both for local development and the environments. A benefit of this is that environment variables & secrets are managed consistently throughout the lifecycle

See the Dockerfile and compose.yml for details

Local development

Setup

Libraries: Ensure the python virtual environment is configured and libraries are installed using requirements-dev.txt, as above

Environment variables: compose/aws.env

Secrets: compose/secrets.env. You need to create this, as it's excluded from version control.

Development

The app can be run locally using Docker compose. This template contains a local environment with:

• Localstack
• MongoDB
• This service

To run the application in development mode:

docker compose watch

Testing

Ensure the python virtual environment is configured and libraries are installed using requirements-dev.txt, as above

Testing follows the FastApi documented approach; using pytest & starlette.

To test the application run:

pytest

Production

To mimic the application running in `production mode locally run:

docker compose up --build -d

Stop the application with

docker compose down

API endpoints

Endpoint	Description
GET: /docs	Automatic API Swagger docs
GET: /example	Simple example

Custom Cloudwatch Metrics

Uses the aws embedded metrics library. An example can be found in metrics.py

In order to make this library work in the environments, the environment variable AWS_EMF_ENVIRONMENT=local is set in the app config. This tells the library to use the local cloudwatch agent that has been configured in CDP, and uses the environment variables set up in CDP AWS_EMF_AGENT_ENDPOINT, AWS_EMF_LOG_GROUP_NAME, AWS_EMF_LOG_STREAM_NAME, AWS_EMF_NAMESPACE, AWS_EMF_SERVICE_NAME

Pipelines

Dependabot

We have added an example dependabot configuration file to the repository. You can enable it by renaming the .github/example.dependabot.yml to .github/dependabot.yml

SonarCloud

Instructions for setting up SonarCloud can be found in sonar-project.properties

Licence

THIS INFORMATION IS LICENSED UNDER THE CONDITIONS OF THE OPEN GOVERNMENT LICENCE found at:

http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3

The following attribution statement MUST be cited in your products and applications when using this information.

Contains public sector information licensed under the Open Government license v3

About the licence

The Open Government Licence (OGL) was developed by the Controller of Her Majesty's Stationery Office (HMSO) to enable information providers in the public sector to license the use and re-use of their information under a common open licence.

It is designed to encourage use and re-use of information freely and flexibly, with only a few conditions.