Create health check endpoint

This is to prevent livenessProbe spamming of index page

blockerbugs/controllers/main.py

@@ -279,6 +279,23 @@ def index():
     return display_current()
 
 
+@main.route('/_health')
+def get_health_check():
+    """Endpoint for OpenShift pod health checks (liveness and readiness probes).
+
+    Verifies database connectivity and returns HTTP 200 on success, 500 on failure.
+    """
+    try:
+        # Simple DB query to verify database connectivity
+        db.session.execute(db.text('SELECT 1')).scalar()
+        response = make_response('OK')
+        response.mimetype = 'text/plain'
+        return response
+    except Exception as e:  # pylint: disable=broad-except
+        app.logger.error('Health check failed: %s', e)
+        abort(500)
+
+
 @main.route('/<int:num>/<release_name>')
 def old_display_buglist(num, release_name):
     return redirect(url_for('.display_buglist', num=num, release_name=release_name))

testing/test_controllers.py

@@ -1,7 +1,9 @@
 import datetime
 import re
+from unittest.mock import patch
 
 import pytest
+import sqlalchemy.exc
 
 from blockerbugs.models.milestone import Milestone
 from blockerbugs.models.release import Release
@@ -490,3 +492,29 @@ class TestGetFunctions:
                 # make sure there are no additional updates listed
                 matches = re.findall(re.escape('<tr class="update">'), html)
                 assert len(matches) == len(bug.updates.all())
+
+
+@pytest.mark.usefixtures('_postgres_db')
+class TestHealthCheck:
+    """Tests for the /_health endpoint"""
+
+    @pytest.fixture(autouse=True)
+    def setup_client(self):
+        """Set up a Flask test client for each test."""
+        self.client = app.test_client()
+
+    def test_health_check_returns_200_when_db_is_accessible(self):
+        """GET /_health returns HTTP 200 with body 'OK' when the DB is reachable."""
+        rv = self.client.get('/_health')
+        assert rv.status_code == 200
+        assert rv.data == b'OK'
+        assert rv.content_type == 'text/plain; charset=utf-8'
+
+    def test_health_check_returns_500_when_db_is_unreachable(self):
+        """GET /_health returns HTTP 500 when the DB query raises an exception."""
+        db_error = sqlalchemy.exc.OperationalError(
+            'SELECT 1', {}, Exception('connection refused')
+        )
+        with patch.object(db.session, 'execute', side_effect=db_error):
+            rv = self.client.get('/_health')
+        assert rv.status_code == 500