django-health-check =================== |version| |pyversion| |djversion| |license| This project checks for various conditions and provides reports when anomalous behavior is detected. The following health checks are bundled with this project: - cache - database - storage - disk and memory utilization (via ``psutil``) - AWS S3 storage - Celery task queue - Celery ping - RabbitMQ - Migrations Writing your own custom health checks is also very quick and easy. We also like contributions, so don’t be afraid to make a pull request. Use Cases --------- The primary intended use case is to monitor conditions via HTTP(S), with responses available in HTML and JSON formats. When you get back a response that includes one or more problems, you can then decide the appropriate course of action, which could include generating notifications and/or automating the replacement of a failing node with a new one. If you are monitoring health in a high-availability environment with a load balancer that returns responses from multiple nodes, please note that certain checks (e.g., disk and memory usage) will return responses specific to the node selected by the load balancer. Supported Versions ------------------ We officially only support the latest version of Python as well as the latest version of Django and the latest Django LTS version. Installation ------------ First, install the ``django-health-check`` package: .. code:: shell $ pip install django-health-check Add the health checker to a URL you want to use: .. code:: python urlpatterns = [ # ... url(r'^ht/', include('health_check.urls')), ] Add the ``health_check`` applications to your ``INSTALLED_APPS``: .. code:: python INSTALLED_APPS = [ # ... 'health_check', # required 'health_check.db', # stock Django health checkers 'health_check.cache', 'health_check.storage', 'health_check.contrib.migrations', 'health_check.contrib.celery', # requires celery 'health_check.contrib.celery_ping', # requires celery 'health_check.contrib.psutil', # disk and memory utilization; requires psutil 'health_check.contrib.s3boto3_storage', # requires boto3 and S3BotoStorage backend 'health_check.contrib.rabbitmq', # requires RabbitMQ broker 'health_check.contrib.redis', # requires Redis broker ] **Note:** If using ``boto 2.x.x`` use ``health_check.contrib.s3boto_storage`` (Optional) If using the ``psutil`` app, you can configure disk and memory threshold settings; otherwise below defaults are assumed. If you want to disable one of these checks, set its value to ``None``. .. code:: python HEALTH_CHECK = { 'DISK_USAGE_MAX': 90, # percent 'MEMORY_MIN': 100, # in MB } If using the DB check, run migrations: .. code:: shell $ django-admin migrate To use the RabbitMQ healthcheck, please make sure that there is a variable named ``BROKER_URL`` on django.conf.settings with the required format to connect to your rabbit server. For example: .. code:: python BROKER_URL = "amqp://myuser:mypassword@localhost:5672/myvhost" To use the Redis healthcheck, please make sure that there is a variable named ``REDIS_URL`` on django.conf.settings with the required format to connect to your redis server. For example: .. code:: python REDIS_URL = "redis://localhost:6370" The cache healthcheck tries to write and read a specific key within the cache backend. It can be customized by setting ``HEALTHCHECK_CACHE_KEY`` to another value: .. code:: python HEALTHCHECK_CACHE_KEY = "custom_healthcheck_key" Setting up monitoring --------------------- You can use tools like Pingdom, StatusCake or other uptime robots to monitor service status. The ``/ht/`` endpoint will respond with an HTTP 200 if all checks passed and with an HTTP 500 if any of the tests failed. Getting machine-readable JSON reports If you want machine-readable status reports you can request the ``/ht/`` endpoint with the ``Accept`` HTTP header set to ``application/json`` or pass ``format=json`` as a query parameter. The backend will return a JSON response: .. code:: shell $ curl -v -X GET -H "Accept: application/json" http://www.example.com/ht/ > GET /ht/ HTTP/1.1 > Host: www.example.com > Accept: application/json > < HTTP/1.1 200 OK < Content-Type: application/json { "CacheBackend": "working", "DatabaseBackend": "working", "S3BotoStorageHealthCheck": "working" } $ curl -v -X GET http://www.example.com/ht/?format=json > GET /ht/?format=json HTTP/1.1 > Host: www.example.com > < HTTP/1.1 200 OK < Content-Type: application/json { "CacheBackend": "working", "DatabaseBackend": "working", "S3BotoStorageHealthCheck": "working" } Writing a custom health check ----------------------------- Writing a health check is quick and easy: .. code:: python from health_check.backends import BaseHealthCheckBackend class MyHealthCheckBackend(BaseHealthCheckBackend): #: The status endpoints will respond with a 200 status code #: even if the check errors. critical_service = False def check_status(self): # The test code goes here. # You can use `self.add_error` or # raise a `HealthCheckException`, # similar to Django's form validation. pass def identifier(self): return self.__class__.__name__ # Display name on the endpoint. After writing a custom checker, register it in your app configuration: .. code:: python from django.apps import AppConfig from health_check.plugins import plugin_dir class MyAppConfig(AppConfig): name = 'my_app' def ready(self): from .backends import MyHealthCheckBackend plugin_dir.register(MyHealthCheckBackend) Make sure the application you write the checker into is registered in your ``INSTALLED_APPS``. Customizing output ------------------ You can customize HTML or JSON rendering by inheriting from ``MainView`` in ``health_check.views`` and customizing the ``template_name``, ``get``, ``render_to_response`` and ``render_to_response_json`` properties: .. code:: python # views.py from health_check.views import MainView class HealthCheckCustomView(MainView): template_name = 'myapp/health_check_dashboard.html' # customize the used templates def get(self, request, *args, **kwargs): plugins = [] status = 200 # needs to be filled status you need # ... if 'application/json' in request.META.get('HTTP_ACCEPT', ''): return self.render_to_response_json(plugins, status) return self.render_to_response(plugins, status) def render_to_response(self, plugins, status): # customize HTML output return HttpResponse('COOL' if status == 200 else 'SWEATY', status=status) def render_to_response_json(self, plugins, status): # customize JSON output return JsonResponse( {str(p.identifier()): 'COOL' if status == 200 else 'SWEATY' for p in plugins}, status=status ) # urls.py import views urlpatterns = [ # ... url(r'^ht/$', views.HealthCheckCustomView.as_view(), name='health_check_custom'), ] Django command -------------- You can run the Django command ``health_check`` to perform your health checks via the command line, or periodically with a cron, as follow: .. code:: shell django-admin health_check This should yield the following output: :: DatabaseHealthCheck ... working CustomHealthCheck ... unavailable: Something went wrong! Similar to the http version, a critical error will cause the command to quit with the exit code ``1``. Other resources --------------- - `django-watchman `__ is a package that does some of the same things in a slightly different way. .. |version| image:: https://img.shields.io/pypi/v/django-health-check.svg :target: https://pypi.python.org/pypi/django-health-check/ .. |pyversion| image:: https://img.shields.io/pypi/pyversions/django-health-check.svg :target: https://pypi.python.org/pypi/django-health-check/ .. |djversion| image:: https://img.shields.io/pypi/djversions/django-health-check.svg :target: https://pypi.python.org/pypi/django-health-check/ .. |license| image:: https://img.shields.io/badge/license-MIT-blue.svg :target: https://pypi.python.org/pypi/django-health-check/