django-probes

Django-probes |latest-version|

|checks-status| |tests-status| |python-support| |license|

Provides a Django management command to check whether the primary database is ready to accept connections.

Run this command in a Kubernetes or OpenShift Init Container_ to make your Django application wait until the database is available (e.g. to run database migrations).

Why Should I Use This App?

wait_for_database is a single command for all database engines Django supports. It automatically checks the database you have configured in your Django project settings. No need to code a specific wait command for Postgres, MariaDB, Oracle, etc., no need to pull a database engine specific container just for running the database readiness check.

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.. _Init Container: https://kubernetes.io/docs/concepts/workloads/pods/init-containers/

Installation

The easiest way to install django-probes is with pip

.. code:: console

$ pip install django-probes

Basic Usage

1. Add django-probes to your Django application:

.. code:: python

INSTALLED_APPS = [
    ...
    'django_probes',
]

2. Add an Init Container_ to your Kubernetes/OpenShift deployment configuration, which calls the wait_for_database management command:

.. code:: yaml

- kind: Deployment
  apiVersion: apps/v1
  spec:
    template:
      spec:
        initContainers:
        - name: wait-for-database
          image: my-django-app:latest
          envFrom:
          - secretRef:
              name: django
          command: ['python', 'manage.py', 'wait_for_database']

Use with Your Own Command

Alternatively, you can integrate the wait_for_database command in your own management command, and do things like database migration, load initial data, etc. with roughly the same Kubernetes setup as above.

.. code:: python

from django.core.management import call_command

# ...
call_command('wait_for_database')

Command Line Options

The management command comes with sane defaults, which you can override if needed:

:--timeout, -t: how long to wait for the database before timing out (seconds), default: 180 :--stable, -s: how long to observe whether connection is stable (seconds), default: 5 :--wait-when-down, -d: delay between checks when database is down (seconds), default: 2 :--wait-when-alive, -a: delay between checks when database is up (seconds), default: 1 :--database: which database of settings.DATABASES to wait for, default: default