Allow healthcheck to work in host_matching mode

When a Flask app is running in `host_matching` mode, it will only route
inbound requests to registered endpoints that set a `host` parameter on
the route.

In order to register a view against all hosts, you can use route
variables like normal, so `<host>` will match any route and pass the
value through as the variable `host` to the view.

CHANGELOG.md

@@ -1,3 +1,7 @@
+### 5.3.0
+
+* Update the Healthcheck to support apps running in `host_matching` mode.
+
 ### 5.2.0
 
 * Adding check internal user functionality and adding FAB and Form Designer to list of supported apps

fsd_utils/healthchecks/healthcheck.py

@@ -6,10 +6,10 @@
 class Healthcheck(object):
     def __init__(self, app):
         self.flask_app = app
-        self.flask_app.add_url_rule("/healthcheck", view_func=self.healthcheck_view)
+        self.flask_app.add_url_rule("/healthcheck", view_func=self.healthcheck_view, host="<host>")
         self.checkers = []
 
-    def healthcheck_view(self):
+    def healthcheck_view(self, host=None):
         responseCode = 200
         response = {"checks": []}
         version = os.getenv("GITHUB_SHA")

pyproject.toml

@@ -5,7 +5,7 @@ build-backend = "setuptools.build_meta"
 [project]
 name = "funding-service-design-utils"
 
-version = "5.2.0"
+version = "5.3.0"
 
 authors = [
   { name="MHCLG", email="FundingService@communities.gov.uk" },

tests/test_healthcheck.py

@@ -10,14 +10,14 @@ class TestHealthcheck:
     def testHealthChecksSetup(self):
         test_app = Mock()
         health = Healthcheck(test_app)
-        test_app.add_url_rule.assert_called_with("/healthcheck", view_func=ANY)
+        test_app.add_url_rule.assert_called_with("/healthcheck", view_func=ANY, host="<host>")
         assert health.checkers == [], "Checks not initialised"
 
     @mock.patch.dict(os.environ, clear=True)
     def testWithNoChecks(self):
         mock_app = Mock()
         health = Healthcheck(mock_app)
-        mock_app.add_url_rule.assert_called_with("/healthcheck", view_func=ANY)
+        mock_app.add_url_rule.assert_called_with("/healthcheck", view_func=ANY, host="<host>")
 
         expected_dict = {"checks": []}
 
@@ -29,7 +29,7 @@ def testWithNoChecks(self):
     def testWithChecksPassing_mocks(self, flask_test_client):
         test_app = Mock()
         health = Healthcheck(test_app)
-        test_app.add_url_rule.assert_called_with("/healthcheck", view_func=ANY)
+        test_app.add_url_rule.assert_called_with("/healthcheck", view_func=ANY, host="<host>")
 
         expected_dict = {"checks": [{"check_a": "ok"}, {"check_b": "ok"}]}
 
@@ -50,7 +50,7 @@ def testWithChecksPassing_mocks(self, flask_test_client):
     def testWithChecksFailing_mocks(self, flask_test_client):
         test_app = Mock()
         health = Healthcheck(test_app)
-        test_app.add_url_rule.assert_called_with("/healthcheck", view_func=ANY)
+        test_app.add_url_rule.assert_called_with("/healthcheck", view_func=ANY, host="<host>")
 
         expected_dict = {"checks": [{"check_a": "fail"}, {"check_b": "ok"}]}
 
@@ -71,7 +71,7 @@ def testWithChecksFailing_mocks(self, flask_test_client):
     def testWithChecksException_mocks(self, flask_test_client):
         test_app = Mock()
         health = Healthcheck(test_app)
-        test_app.add_url_rule.assert_called_with("/healthcheck", view_func=ANY)
+        test_app.add_url_rule.assert_called_with("/healthcheck", view_func=ANY, host="<host>")
 
         expected_dict = {"checks": [{"check_a": "fail"}, {"check_b": "Failed - check logs"}]}