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⚙️ Adds Django 4.2 support and fixes trove classifiers (#363)
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* ⚙️ Adds Django 4.2 support and fixes trove classifiers

* :shirts: Runs black on code to make CI happy

* :shirts: Runs isort on code to make CI happy

* 💚 Updates test to match exception copy

* 📝 mirrors old README.rst to make docs work

Not a great solution, but a workaround.

* ⚙️ Adds pip cache support

* 🔥 Removes 4.0 from grid because it's no longer supported

* ⚙️ Updates cache-key

This isn't really used, but I think having caching is a win

* ⚙️ Adds missing file

* 🔥 Removes cache line

* Fix storages deprecation warnings (#372)

* ⚙️ Adds Django 4.2 support and fixes trove classifiers

* :shirts: Runs black on code to make CI happy

* :shirts: Runs isort on code to make CI happy

* 💚 Updates test to match exception copy

* 📝 mirrors old README.rst to make docs work

Not a great solution, but a workaround.

* ⚙️ Adds pip cache support

* 🔥 Removes 4.0 from grid because it's no longer supported

* ⚙️ Updates cache-key

This isn't really used, but I think having caching is a win

* ⚙️ Adds missing file

* 🔥 Removes cache line

* Fix storages deprecation warnings

---------

Co-authored-by: Jeff Triplett <[email protected]>

* Fix isort ordering

---------

Co-authored-by: Bruno Alla <[email protected]>
Co-authored-by: Frank Wiles <[email protected]>
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3 people authored Oct 19, 2023
1 parent 9f9810a commit cc657b3
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8 changes: 7 additions & 1 deletion .github/workflows/ci.yml
Original file line number Diff line number Diff line change
Expand Up @@ -35,6 +35,8 @@ jobs:
- uses: actions/setup-python@v4
with:
python-version: "3.x"
cache: 'pip'
cache-dependency-path: '**/pyproject.toml'
- run: python -m pip install --upgrade pip build wheel twine
- run: python -m build --sdist --wheel
- run: python -m twine check dist/*
Expand All @@ -49,6 +51,8 @@ jobs:
uses: actions/setup-python@v4
with:
python-version: "3.10"
cache: 'pip'
cache-dependency-path: '**/pyproject.toml'
- run: python -m pip install -e .[docs]
- run: python -m sphinx -b html -W docs docs/_build

Expand All @@ -65,14 +69,16 @@ jobs:
django-version:
- "2.2"
- "3.2"
- "4.0"
- "4.1"
- "4.2"
steps:
- uses: actions/checkout@v3
- name: Setup Python version ${{ matrix.python-version }}
uses: actions/setup-python@v4
with:
python-version: ${{ matrix.python-version }}
cache: 'pip'
cache-dependency-path: '**/pyproject.toml'
- run: python -m pip install .[test]
- run: python -m pip install Django~="${{ matrix.django-version }}.0"
- run: python -m pytest
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292 changes: 291 additions & 1 deletion docs/readme.rst
Original file line number Diff line number Diff line change
@@ -1 +1,291 @@
.. include:: ../README.rst
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 <https://github.com/mwarkentin/django-watchman>`__
is a package that does some of the same things in a slightly
different way.
- See this
`weblog <https://www.vincit.fi/en/blog/deploying-django-to-elastic-beanstalk-with-https-redirects-and-functional-health-checks/>`__
about configuring Django and health checking with AWS Elastic Load
Balancer.

.. |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/
4 changes: 3 additions & 1 deletion health_check/contrib/rabbitmq/backends.py
Original file line number Diff line number Diff line change
Expand Up @@ -19,7 +19,9 @@ def check_status(self):
"""Check RabbitMQ service by opening and closing a broker channel."""
logger.debug("Checking for a broker_url on django settings...")

broker_url_setting_key = f"{self.namespace}_BROKER_URL" if self.namespace else "BROKER_URL"
broker_url_setting_key = (
f"{self.namespace}_BROKER_URL" if self.namespace else "BROKER_URL"
)
broker_url = getattr(settings, broker_url_setting_key, None)

logger.debug("Got %s as the broker_url. Connecting to rabbit...", broker_url)
Expand Down
1 change: 0 additions & 1 deletion health_check/db/migrations/0001_initial.py
Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,6 @@


class Migration(migrations.Migration):

initial = True

replaces = [
Expand Down
21 changes: 17 additions & 4 deletions health_check/storage/backends.py
Original file line number Diff line number Diff line change
@@ -1,8 +1,13 @@
import uuid

import django
from django.conf import settings
from django.core.files.base import ContentFile
from django.core.files.storage import get_storage_class

if django.VERSION >= (4, 2):
from django.core.files.storage import InvalidStorageError, storages
else:
from django.core.files.storage import get_storage_class

from health_check.backends import BaseHealthCheckBackend
from health_check.exceptions import ServiceUnavailable
Expand All @@ -22,13 +27,20 @@ class MyStorageHealthCheck(StorageHealthCheck):
(e.g 'django.core.files.storage.FileSystemStorage') or a Storage instance.
"""

storage_alias = None
storage = None

def get_storage(self):
if isinstance(self.storage, str):
return get_storage_class(self.storage)()
if django.VERSION >= (4, 2):
try:
return storages[self.storage_alias]
except InvalidStorageError:
return None
else:
return self.storage
if isinstance(self.storage, str):
return get_storage_class(self.storage)()
else:
return self.storage

def get_file_name(self):
return "health_check_storage_test/test-%s.txt" % uuid.uuid4()
Expand Down Expand Up @@ -68,4 +80,5 @@ def check_status(self):


class DefaultFileStorageHealthCheck(StorageHealthCheck):
storage_alias = "default"
storage = settings.DEFAULT_FILE_STORAGE
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