How can I detect Heroku's environment?

Question

I have a Django webapp, and I\'d like to check if it\'s running on the Heroku stack (for conditional enabling of debugging, etc.) Is there any simple way to do this? An envi

Answer 1

DATABASE_URL environment variable

in_heroku = False
if 'DATABASE_URL' in os.environ:
    in_heroku = True

I think you need to enable the database for your app with:

heroku addons:create heroku-postgresql:hobby-dev

but it is free and likely what you are going to do anyways.

Heroku makes this environment variable available when running its apps, in particular for usage as:

import dj_database_url
if in_heroku:
    DATABASES = {'default': dj_database_url.config()}
else:
    DATABASES = {
        'default': {
            'ENGINE': 'django.db.backends.sqlite3',
            'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
        }
    }

Not foolproof as that variable might be defined locally, but convenient for simple cases.

heroku run env

might also show other possible variables like:

• DYNO_RAM
• WEB_CONCURRENCY

but I'm not sure if those are documented like DATABASE_URL.