Bullet Train REST API

Development Environment

Before running the application, you'll need to configure a database for the application. The steps to do this can be found in the following section entitled 'Databases'.

pip install pipenv
pipenv install
pipenv run python src/manage.py migrate 
pipenv run python src/manage.py runserver

The application can also be run locally using Docker Compose if required, however, it's beneficial to run locally using the above steps as it gives you hot reloading. To run using docker compose, simply run the following command from the project root:

docker-compose up

Databases

Databases are configured in app/settings/<env>.py

The app is configured to use PostgreSQL for all environments.

When running locally, you'll need a local instance of postgres running. The easiest way to do this is to use docker which is achievable with the following command:

docker run --name local_postgres -d -P postgres

You'll also need to ensure that you have a value for POSTGRES_PASSWORD set as an environment variable on your development machine.

When running on a Heroku-ish platform, the application reads the database connection in production from an environment variable called DATABASE_URL. This should be configured in the Heroku-ish application configuration.

When running the application using Docker, it reads the database configuration from the settings located in app.settings.master-docker

Initialising

Locally

The application is built using django which comes with a handy set of admin pages available at /admin/. To access these, you'll need to create a super user. This can be done with the following command:

pipenv run python src/manage.py createsuperuser

Once you've created the super user, you can use the details to log in at /admin/. From here, you can create an organisation and either create another user or simply assign the organisation to your admin user to begin using the application.

In a Heroku-ish environment

Once the app has been deployed, you can initialise it to create a super user by sending a GET request to the /api/v1/users/init/ endpoint. This will create a super user with the details configured in app.settings.common with the following parameters:

ADMIN_USERNAME,
ADMIN_EMAIL,
ADMIN_INITIAL_PASSWORD

Note that this functionality can be turned off in the settings if required by setting ALLOW_ADMIN_INITIATION_VIA_URL=False.

Deploying

Using Heroku-ish Platform (e.g. Heroku, Dokku, Flynn)

The application should run on any Heroku-ish platform (e.g. Dokku, Flynn) by simply adding the required git repo and pushing the code. The code for running the app is contained in the Procfile.

To get it running, you'll need to add the necessary config variables as outlined below.

Using ElasticBeanstalk

The application will run within ElasticBeanstalk using the default Python setup. We've included the .ebextensions/ and .elasticbeanstalk/ directories which will run on ElasticBeanstalk.

The changes required to run in your environment will be as follows

.elasticbeanstalk/config.yml - update application_name and default_region to the relevant variables for your setup.

.ebextensions/options.config - within the root of the project generate.sh will add in all environment variables that are required using your chosen CI/CD. Alternatively, you can add your own options.config.

Using Docker

The application can be configured to run using docker with simply by running the following command:

docker-compose up

This will use some default settings created in the docker-compose.yml file located in the root of the project. These should be changed before using in any production environments.

Environment Variables

The application relies on the following environment variables to run:

DJANGO_ALLOWED_HOSTS: comma separated list of hosts the application will run on in the given environment
DJANGO_SETTINGS_MODULE: python path to settings file for the given environment, e.g. "app.settings.develop"
SENDGRID_API_KEY: API key from sendgrid account which will need to be set up for emails to be sent from platform successfully
DATABASE_URL: required by develop and master environments, should be a standard format database url e.g. postgres://user:password@host:port/db_name
DJANGO_SECRET_KEY: see 'Creating a secret key' section below
GOOGLE_ANALYTICS_KEY: if google analytics is required, add your tracking code
GOOGLE_SERVICE_ACCOUNT: service account json for accessing the google API, used for getting usage of an organisation - needs access to analytics.readonly scope
INFLUXDB_TOKEN: If you want to send API events to InfluxDB, specify this write token.
INFLUXDB_URL: The URL for your InfluxDB database
INFLUXDB_ORG: The organisation string for your InfluxDB API call.
GA_TABLE_ID: GA table ID (view) to query when looking for organisation usage
USE_S3_STORAGE: 'True' to store static files in s3
AWS_STORAGE_BUCKET_NAME: bucket name to store static files. Required if `USE_S3_STORAGE' is true.
AWS_S3_REGION_NAME: region name of the static files bucket. Defaults to eu-west-2.
ALLOWED_ADMIN_IP_ADDRESSES: restrict access to the django admin console to a comma separated list of IP addresses (e.g. 127.0.0.1,127.0.0.2)

Creating a secret key

It is important to also set an environment variable on whatever platform you are using for DJANGO_SECRET_KEY. There is a function to create one in app.settings.common if none exists in the environment variables, however, this is not suitable for use in production. To generate a new secret key, you can use the function defined in src/secret-key-gen.py by simply running it from a command prompt:

python secret-key-gen.py

Adding dependencies

To add a python dependency, run the following commands:

pipenv install <package name>

The dependency then needs to be added to the relevant requirements*.txt files as necessary.

Caching

The application makes use of caching in a couple of locations:

Environment authentication - the application utilises an in memory cache for the environment object on all endpoints that use the X-Environment-Key header.
Environment flags - the application utilises an in memory cache for the flags returned when calling /flags. The number of seconds this is cached for is configurable using the environment variable "CACHE_FLAGS_SECONDS"

Stack

Python 2.7.14
Django 1.11.13
DjangoRestFramework 3.8.2

Static Files

Although the application relies on very few static files, it is possible to optimise their configuration to host these static files in S3. This is done using the relevant environment variables provided above. Note, however, that in order to use the configuration, the environment that you are hosting on must have the correct AWS credentials configured. This can be done using environment variables or, in the case of AWS hosting such as Elastic Beanstalk, you can add the correct permissions to the EC2 Role. The role will need full access to the specific bucket that the static files are hosted in.

Code Examples

Youtube Tutorials

euprogramador/bullet-train-api