Merge pull request #14 from communitiesuk/fs-1306-healthchecks

Fs 1306 healthchecks

.github/workflows/create-tag-workflow.yml → .github/workflows/test-and-tag.yml

@@ -1,20 +1,43 @@
-name: Create Tag
+name: Test and Tag
 
 
-# This workflow reads the current version from setup.py and then creates a new tag and release named
+# Runs on every push to run the unit tests.
+
+# Additionally, if on main, reads the current version from setup.py and then creates a new tag and release named
 # for that version.
 # If a tag already exists with that name, the Create Release step is skipped.
 
-# Currently version must be manually updated in setup.py to enable this workflow to run
+# Currently version must be manually updated in setup.py to enable this tagging job to run
+
 on:
   workflow_dispatch:
   push:
-    # Should only trigger on main branch
-    branches: [ "main" ]
+    paths-ignore:
+      - "**/README.md"
 
 jobs:
+  run-unit-tests:
+    runs-on: ubuntu-latest
+    permissions:
+        contents: write
+    steps:
+    - uses: actions/checkout@v3
+
+    - name: Setup python
+      id: setup_python
+      uses: actions/setup-python@v4
+      with:
+        python-version: '3.10'
+
+    - name: Run tests
+      run: |
+        python -m venv .venv
+        source .venv/bin/activate && python -m pip install --upgrade pip && pip install -r requirements-dev.txt
+        pytest
   create-release:
     runs-on: ubuntu-latest
+    needs: run-unit-tests
+    if: github.ref == 'refs/heads/main'
     permissions:
         contents: write
     steps:

.gitignore

@@ -78,6 +78,9 @@ Temporary Items
 # *.iml
 # *.ipr
 
+# VS Code
+.vscode/
+
 # CMake
 cmake-build-*/
 

README.md

@@ -3,12 +3,21 @@ Shared library for funding service design apps.
 
 This library can be installed into other python repos and the packages used by those repos.
 
+# Dev setup
+In order to run the unit tests, setup a virtual env and install requirements
+1. Checkout the code
+1. Setup a venv and activate: `python3 -m venv .venv && source .venv/bin/activate`
+1. Install dev requirements: `pip install -r requirements-dev.txt`
+1. Install pre-commit hook: `pre-commit install`
+1. Run tests with `pytest`
+1. If you add any packages needed by services that consume `fsd_utils`, add them into `setup.py`.
+
 # Releasing
 To create a new release of funding-service-design-utils:
 1. Make and test your changes as normal in this repo
 2. Update the `version` tag in `setup.py`
 3. Push your changes to `main`.
-4. The Action at `.github/workflows/create-tag-workflow.yml` will create a new tag and release, named for the version in `setup.py`. This is triggered automatically on a push to main.
+4. The Action at `.github/workflows/test-and-tag.yml` will create a new tag and release, named for the version in `setup.py`. This is triggered automatically on a push to main.
 
 # Usage
 Either of the following options will install the funding-service-design-utils into your python project. The package `fsd_utils` can then be imported.
@@ -27,6 +36,18 @@ To reference the latest commit from a particular branch from pip, add the follow
 ## The configclass
 Currently the configclass allows for pretty print debugging of config keys and the class from which they are created. This allows devs to quickly diagnoise problems arrising from incorrectly set config. To activate this functionality, one must decorate each config class with the `@configclass` decorator.
 
+## Common Config
+This defines config values that are common across different services, eg. url patterns. Usage example:
+
+```
+from fsd_utils import CommonConfig
+
+@configclass
+class DefaultConfig:
+    SECRET_KEY = CommonConfig.SECRET_KEY
+
+```
+
 ## Gunicorn
 The gunicorn utility allows consistent configuration of gunicorn across microservices.
 
@@ -101,3 +122,33 @@ Then - to use the `@login_required` decorator just add it to routes you need to
     def example_route(account_id):
         #...account_id will be available here if the user is authenticated
         #...if not logged in the user will be redirected to re-authenticate
+
+## Healthchecks
+Adds the route `/healthcheck` to an application. On hitting this endpoint, a customisable set of checks are run to confirm the application is functioning as expected and a JSON response is returned.
+
+Response codes:
+- 200: All checks were successful, application is healthy
+- 500: One or more checks failed, application is unhealthy
+
+Example usage:
+```
+from fsd_utils.healthchecks.healthcheck import Healthcheck
+from fsd_utils.healthchecks.checkers import DbChecker, FlaskRunningChecker
+
+health = Healthcheck(flask_app)
+health.add_check(FlaskRunningChecker())
+health.add_check(DbChecker(db))
+```
+The above will initialise the `/healthcheck` url and adds 2 checks.
+
+### Checks
+The following 2 checks are provided in `fsd_utils` in `checkers.py`:
+- `FlaskRunningChecker`: Checks whether a `current_app` is available from flask, returns `True` if it is, `False` if not.
+- `DbChecker`: Runs a simple query against the DB to confirm database availability.
+
+### Implementing custom checks
+Custom checks can be created as subclasses of `CheckerInterface` and should contain a method with the following signature:
+`def check(self) -> Tuple[bool, str]:`
+Where
+- `bool` is a True or False whether the check was successful
+- `str` is a message to display in the result JSON, typically `OK` or `Fail`

fsd_utils/__init__.py

@@ -1,7 +1,15 @@
 from fsd_utils import authentication  # noqa
 from fsd_utils import gunicorn  # noqa
+from fsd_utils import healthchecks
 from fsd_utils import logging  # noqa
-from fsd_utils.config.configclass import configclass  # noqa
 from fsd_utils.config.commonconfig import CommonConfig  # noqa
+from fsd_utils.config.configclass import configclass  # noqa
 
-__all__ = [configclass, logging, gunicorn, authentication, CommonConfig]
+__all__ = [
+    configclass,
+    logging,
+    gunicorn,
+    authentication,
+    CommonConfig,
+    healthchecks,
+]

fsd_utils/config/commonconfig.py

@@ -1,7 +1,6 @@
-from distutils.log import WARN
 import logging
 import os
-from pathlib import Path
+
 
 class CommonConfig:
 
@@ -10,7 +9,7 @@ class CommonConfig:
         "unit_test": logging.DEBUG,
         "dev": logging.INFO,
         "test": logging.WARN,
-        "production": logging.ERROR
+        "production": logging.ERROR,
     }
 
     # ---------------
@@ -23,7 +22,7 @@ class CommonConfig:
     if not FLASK_ENV:
         raise KeyError("FLASK_ENV is not present in environment")
     try:
-        FSD_LOG_LEVEL = FSD_LOG_LEVELS['FLASK_ENV']
+        FSD_LOG_LEVEL = FSD_LOG_LEVELS["FLASK_ENV"]
     except KeyError:
         FSD_LOG_LEVEL = FSD_LOG_LEVELS["production"]
 
@@ -49,7 +48,9 @@ class CommonConfig:
     #  Application hosts, endpoints
     # ---------------
 
-    APPLICATION_STORE_API_HOST = os.getenv("APPLICATION_STORE_API_HOST", TEST_APPLICATION_STORE_API_HOST)
+    APPLICATION_STORE_API_HOST = os.getenv(
+        "APPLICATION_STORE_API_HOST", TEST_APPLICATION_STORE_API_HOST
+    )
     APPLICATIONS_ENDPOINT = "/applications"
     APPLICATION_ENDPOINT = "/applications/{application_id}"
     APPLICATION_STATUS_ENDPOINT = "/applications/{application_id}/status"
@@ -59,15 +60,19 @@ class CommonConfig:
     # Assessment hosts, endpoints
     # ---------------
 
-    ASSESSMENT_STORE_API_HOST = os.getenv("ASSESSMENT_STORE_API_HOST", TEST_ASSESSMENT_STORE_API_HOST)
+    ASSESSMENT_STORE_API_HOST = os.getenv(
+        "ASSESSMENT_STORE_API_HOST", TEST_ASSESSMENT_STORE_API_HOST
+    )
 
     # ---------------
     #  Fund hosts, endpoints
     # ---------------
 
-    FUND_STORE_API_HOST = os.getenv("FUND_STORE_API_HOST", TEST_FUND_STORE_API_HOST)
+    FUND_STORE_API_HOST = os.getenv(
+        "FUND_STORE_API_HOST", TEST_FUND_STORE_API_HOST
+    )
     FUNDS_ENDPOINT = "/funds"
-    FUND_ENDPOINT = "/funds/{fund_id}" #account id in assessment store
+    FUND_ENDPOINT = "/funds/{fund_id}"  # account id in assessment store
 
     ROUNDS_ENDPOINT = "/funds/{fund_id}/rounds"
     ROUND_ENDPOINT = "/funds/{fund_id}/rounds/{round_id}"
@@ -143,4 +148,4 @@ class CommonConfig:
         "session_cookie_samesite": FSD_SESSION_COOKIE_SAMESITE,
         "x_content_type_options": True,
         "x_xss_protection": True,
-    }
+    }

fsd_utils/healthchecks/__init__.py

@@ -0,0 +1,2 @@
+from . import checkers  # noqa
+from . import healthcheck  # noqa

fsd_utils/healthchecks/checkers.py

@@ -0,0 +1,35 @@
+from typing import Tuple
+
+from flask import current_app
+
+
+class CheckerInterface:
+    def check(self) -> Tuple[bool, str]:
+        pass
+
+
+class FlaskRunningChecker(CheckerInterface):
+    def __init__(self):
+        self.name = "check_running"
+
+    def check(self):
+        if current_app:
+            return True, "OK"
+        else:
+            return False, "Fail"
+
+
+class DbChecker(CheckerInterface):
+    def __init__(self, db):
+        self.db = db
+        self.name = "check_db"
+
+    def check(self):
+        from sqlalchemy.exc import SQLAlchemyError
+
+        try:
+            self.db.session.execute("SELECT 1")
+            return True, "OK"
+        except SQLAlchemyError:
+            current_app.logger.exception("DB Check failed")
+            return False, "Fail"

fsd_utils/healthchecks/healthcheck.py

@@ -0,0 +1,35 @@
+from flask import current_app
+
+
+class Healthcheck(object):
+    def __init__(self, app):
+        self.flask_app = app
+        self.flask_app.add_url_rule(
+            "/healthcheck", view_func=self.healthcheck_view
+        )
+        self.checkers = []
+
+    def healthcheck_view(self):
+        responseCode = 200
+        response = {"checks": []}
+        for checker in self.checkers:
+            try:
+                result = checker.check()
+                current_app.logger.debug(
+                    f"Check {checker.name} returned {result}"
+                )
+                response["checks"].append({checker.name: result[1]})
+                if result[0] is False:
+                    responseCode = 500
+            except Exception:
+                response["checks"].append(
+                    {checker.name: "Failed - check logs"}
+                )
+                current_app.logger.exception(
+                    f"Check {checker.name} failed with an exception"
+                )
+                responseCode = 500
+        return response, responseCode
+
+    def add_check(self, checker):
+        self.checkers.append(checker)

pytest.ini

@@ -0,0 +1,4 @@
+[pytest]
+env =
+    FLASK_ENV=unit_test
+    FLASK_DEBUG=1

requirements-dev.txt

@@ -0,0 +1,5 @@
+-e .
+
+pre-commit
+pytest-env>=0.6.2
+sqlalchemy==1.4.39

setup.py

@@ -17,7 +17,7 @@
 
 setup_kwargs = {
     "name": "funding-service-design-utils",
-    "version": "0.0.11",
+    "version": "0.0.12",
     "description": "Utils for the fsd-tech team",
     "long_description": None,
     "author": "DLUHC",

tests/conftest.py

@@ -0,0 +1,23 @@
+"""
+Contains test configuration.
+"""
+import pytest
+from flask import Flask
+
+
+def create_app():
+    app = Flask("test")
+    return app
+
+
+@pytest.fixture(scope="function")
+def flask_test_client():
+    """
+    Creates the test client we will be using to test the responses
+    from our app, this is a test fixture.
+    :return: A flask test client.
+    """
+
+    with create_app().app_context() as app_context:
+        with app_context.app.test_client() as test_client:
+            yield test_client