Simple healthcheck endpoint for Pyramid, with maintenance mode and application checks.
- PyPI: https://pypi.python.org/pypi/pyramid_health
- Bitbucket: https://bitbucket.org/Ludia/pyramid_health
Install using setuptools, e.g. (within a virtualenv):
$ pip install pyramid_health
Once pyramid_health is installed, you must use the config.include mechanism to include it into your Pyramid project's configuration. In your Pyramid project's __init__.py:
config = Configurator(.....) config.include('pyramid_health')
Alternately you can use the pyramid.includes configuration value in your .ini file:
[app:myapp] pyramid.includes = pyramid_health
Pyramid_health configuration (values are defaults):
[app:myapp] healthcheck.url = /health healthcheck.disablefile = /tmp/maintenance # touch this file to activate healthcheck.maintenance_code = 299 # Code to return in maintenance mode healthcheck.failure_code = 503 # Code to return when one or more checks fail
When your application is healthy, pyramid_health endpoint returns 200 OK. When you enable the maintenance mode, the endpoint returns 299 MAINTENANCE and logs Health response: MAINTENANCE. If the request to the healthcheck endpoint asks for the application checks, and one application check or more return an error, the endpoint returns 503 ERROR and logs Health response: ERROR (<all-check-results>).
The application checks are routines in your application that subscribe to pyramid_health.HealthCheckEvent event, execute a specific health check and report the outcome as a status (OK or ERROR) and an optional message.
The application checks are not called unless you explicitely request it with the request param checks set to true or all (like: GET /health?checks=all)
To add an application check in your application:
from pyramid.events import subscriber from pyramid_health import HealthCheckEvent @subscriber(HealthCheckEvent) def db_check(event): try: db.ping() except: event.report(name='db', status='NOK', message='ping failed') else: event.report(name='db', status='OK')
- You may or may not report succeeding checks
In maintenance mode, the healthcheck endpoint's response is changed to inform the HTTP client that this backend is unavailable. Typically a loadbalancer polling the backends would stop sending traffic to a backend in maintenance mode.
The response status code is 299 MAINTENANCE by default. You can change it with healthcheck.maintenance_code.