Usage¶

To use fab_support in a project add:

import fab_support

You will then need a fabfile.py like this:

from fabric.api import env
import os
import time


import fab_support


# Operating System Environment variables have precedence over variables defined in the .env file,
# that is to say variables from the .env files will only be used if not defined
# as environment variables.
# Load operating system environment variables and then prepare to use them
os_env = environ.Env()
env_file = '.env'
print('Loading : {}  See {} for more info'.format(env_file, __name__))
os_env.read_env(env_file)


# Definition of different environments to deploy to
env['stages'] = {
    'local': {
        'comment': 'FAC Galleria local version',
        'ENV': {
            'DJANGO_SECRET_KEY' : os.getenv('DJANGO_SECRET_KEY_LOCAL'),
        },
        'GIT_BRANCH': 'test'
    },
    'uat': {
        'comment' : 'www.drummonds.net UAT',
        'ENV': {
            'DJANGO_SECRET_KEY' : os.getenv('DJANGO_SECRET_KEY_LOCAL'), # same as local
        },
        'DJANGO_SETTINGS_MODULE' : 'drummonds_net.settings.production',  # UAT same as production
        'HEROKU_APP_NAME' : 'drummonds-uat',
        'HEROKU_PROD_APP_NAME': 'drummonds-prod',
        'HEROKU_POSTGRES_TYPE' : 'hobby-basic',  # Need more than 10,000 rows allows to 10M rows but costs $9 a month
        'PRODUCTION_URL' : 'uat.drummonds.net',
        'DJANGO_SECRET_KEY' : os.getenv('DJANGO_SECRET_KEY'),
        'DJANGO_ALLOWED_HOSTS' : '.herokuapp.com,.drummonds.net',
        'DJANGO_SENTRY_DSN' : 'https://b1a_very:_secrete6b34d18@sentry.io/1170320',
        'GIT_BRANCH' : 'uat'
    },
    'prod': {
        'comment' : 'www.drummonds.net production',
        'ENV': {
            'DJANGO_SECRET_KEY' : os.getenv('DJANGO_SECRET_KEY_PROD'),
        },
        'DJANGO_SETTINGS_MODULE' : 'drummonds_net.settings.production',  # UAT same as production
        'HEROKU_APP_NAME' : 'drummonds-prod',
        'HEROKU_POSTGRES_TYPE' : 'hobby-basic',  # Need more than 10,000 rows allows to 10M rows but costs $9 a month
        'PRODUCTION_URL' : 'www.drummonds.net',
        'DJANGO_SECRET_KEY' : os.getenv('DJANGO_SECRET_KEY'),
        'DJANGO_ALLOWED_HOSTS' : '.herokuapp.com,.drummonds.net',
        'DJANGO_SENTRY_DSN' : 'https://b1a_very:_secrete6b34d18@sentry.io@sentry.io/1125110',
        'GIT_BRANCH' : 'master'
    },
}

General variables env[‘stages’]¶

As shown above this is a list of stages. Each stage is a dictionary which has general variables and also an ENV dictionary which has all the environment variables that are to be passed through to the final run time environment.

The documentation breaks down the general definitions here (those that have a meaning in fab_support) and any environment variables that have a special meaning in the next section.

Name	Default	Comments
comment		Identifies which stage this is - used internally eg fab fab_support.list_stages
GIT_BRANCH	master	Which GIT branch to use when building deployment, Required for Heroku deployement when you want to deploy a different branch than master [1].
GIT_PUSH	‘’	For specialised GIT push eg using a subtree ‘git subtree push –prefix tests/demo_django_postgres heroku master’
GIT_PUSH_DIR	‘.’	Local directory to run git push from eg ‘../..’
HEROKU_APP_NAME	fab-support-test-app	Name must start with a letter and can only contain lowercase letters, numbers, and dashes. The production name should end in prod for additional protection [3].
HEROKU_PROD_APP_NAME	fab-support-app-prod	Used to identify where to copy the production data from. Essential for all builds.
HEROKU_OLD_PROD_APP_NAME	fab-support-app-old_prod	Name of production (prod) after promoting uat to prod.
HEROKU_POSTGRES_TYPE	hobby-dev	free to 10K rows, hobby-basic allows to 10M rows but costs $9 a month
PRODUCTION_URL	‘’	This is where the production URL should be hosted. empty string if no remote URL [2].
USES_CELERY	False	If True then will set up on Heroku a scaling worker

[1]	Heroku uses the local git repository to push from by default. So GIT_BRANCH will be the branch in the local repository

[2]	This controls the heroku routing layer which is external to the Django routing layer. The DJANGO_ALLOWED_HOSTS is internal to the Django application and must also match the URL

[3]	This name must be globally distinct for heroku.

[4]	Heroku needs to know what the settings module is and so the name is not passed like a simple environment variable.

Environment variables env[‘stages’][‘stage_x’][‘ENV’]¶

These are the variables that are set in the .env and are carried through to the development environments. stage_x might be uat or prod etc. For heroku this will then involve the commmand line command like this heroku config:set DJANGO_SECRET=very_secret.

A common pattern is to use a single .env file to store all the secrets and then to use this dictionary to allocate the secrets to the same environment variable in different stages eg:

# Not a complete file but for illustration
env['stages'] = {
    'local': {
        'ENV': {
            'DJANGO_SECRET_KEY' : os.getenv('DJANGO_SECRET_KEY_LOCAL'),
        },
    },
    'uat': {
        'ENV': {
            'DJANGO_SECRET_KEY' : os.getenv('DJANGO_SECRET_KEY_UAT'),
        },
    },
    'prod': {
        'ENV': {
            'DJANGO_SECRET_KEY' : os.getenv('DJANGO_SECRET_KEY_PROD'),
        },
    },
}

If an environment variable is listed here it is because fab_support provides a default or takes some other action with it.

Name	Default	Comments
DJANGO_SETTINGS_MODULE	{{app_name}}	Two scoops config.settings.test or config.settings.production [4].
DJANGO_ALLOWED_HOSTS	Set	Will by default allow the app name setup. See DJANGO_ALLOWED_HOSTS for more details.
PYTHONHASHSEED	random	Heroku default

DJANGO_ALLOWED_HOSTS¶

This pattern was defined by Python django cookiecutter project and is the definition of a environment variable so that [ALLOWED_HOSTS]_ which is a standard Django setting. Then in the settings file you would have code like this:

ALLOWED_HOSTS = env.list('DJANGO_ALLOWED_HOSTS', default=['{{ cookiecutter.domain_name }}'])

Defaults by application type.

Application	Default
Heroku	f’{HEROKU_APP_NAME}.herokuapp.com’