sag_py_fastapi_health

Add health check endpoints to fastapi (similar to the ones dotnet core has)

What it does

• Adds one or multiple health endpoint
• Configurable output format (json or prtg)
• Possibility to add checks (own and pre shipped)
• Pre-Shipped tests for http get requests including basic auth and directory existence/readability/writability

Installation

pip install sag-py-fastapi-health

How to use

Sample usage with existing checks

from sag_py_fastapi_health.checks.http import HttpCheck
from sag_py_fastapi_health.checks.storage import StorageExistsCheck, StorageReadableCheck
from sag_py_fastapi_health.formatter import DefaultResponseFormatter, PrtgResponseFormatter
from sag_py_fastapi_health.models import Probe
from sag_py_fastapi_health.router import HealthcheckRouter

from config import config

router = HealthcheckRouter(
    Probe(
        name="health",
        response_formatter=DefaultResponseFormatter(),
        checks=[
            StorageExistsCheck("/opt/app/data", name="my_dir_exists"),
            StorageReadableCheck("/opt/app/data", name="my_dir_is_readable"),
            HttpCheck("https://localhost/auth", name="auth_available", timeout=5),
        ],
    ),
    Probe(
        name="health-prtg",
        response_formatter=PrtgResponseFormatter(),
        checks=[
            StorageExistsCheck("/opt/app/data", name="my_dir_exists"),
            StorageReadableCheck("/opt/app/data", name="my_dir_is_readable"),
            HttpCheck("https://localhost/auth", name="auth_available", timeout=5),
        ],
    ),
)

Write your own check

from sag_py_fastapi_health.models import CheckResult

class TestCheck(Check):
    def __init__(self, name: str = "check") -> None:
        self._name: str = name

    async def __call__(self) -> CheckResult:
        is_healthy: bool = a_custom_check()
        description: str = "A description of the status or a error message"

        return CheckResult(
            name=self._name,
            status="Healthy" if is_healthy else "Unhealthy",
            description=description,
        )

The description contains something like "Directory ... was accessable" or "Service is running" if everything is ok. If there was an error, you can add the error message/exception message there.

How to configure in prtg

use the sensor "HTTP data advanced" (https://www.paessler.com/manuals/prtg/http_data_advanced_sensor) and configure to your prtg health endpoint (like in the example above ([URL_TO_YOUR_SERVICE]/health/health-prtg)

How to start developing

With vscode

Just install vscode with dev containers extension. All required extensions and configurations are prepared automatically.

With pycharm

• Install latest pycharm
• Install pycharm plugin BlackConnect
• Install pycharm plugin Mypy
• Configure the python interpreter/venv
• pip install requirements-dev.txt
• pip install black[d]
• Ctl+Alt+S => Check Tools => BlackConnect => Trigger when saving changed files
• Ctl+Alt+S => Check Tools => BlackConnect => Trigger on code reformat
• Ctl+Alt+S => Click Tools => BlackConnect => "Load from pyproject.yaml" (ensure line length is 120)
• Ctl+Alt+S => Click Tools => BlackConnect => Configure path to the blackd.exe at the "local instance" config (e.g. C:\Python310\Scripts\blackd.exe)
• Ctl+Alt+S => Click Tools => Actions on save => Reformat code
• Restart pycharm

How to publish

• Update the version in setup.py and commit your change
• Create a tag with the same version number
• Let github do the rest