fix(helm): derive Patroni discovery labels from chart values

k8s-cluster/ha-cluster/helm_charts/templates/statefulset.yaml

@@ -85,7 +85,7 @@ spec:
         - name: PATRONI_KUBERNETES_USE_ENDPOINTS
           value: 'true'
         - name: PATRONI_KUBERNETES_LABELS
-          value: '{application: ivyhac, cluster-name: ivorysql-patroni-hac}'
+          value: {{ dict "application" .Values.applicationName "cluster-name" .Values.clusterName | toJson | quote }}
         - name: PATRONI_KUBERNETES_PORTS
           value: '[{"name": "ivorysql", "port": 5432}]'
         - name: IVORYSQL_PASSWORD

tests/test_helm_labels.py

@@ -0,0 +1,41 @@
+"""Render regression tests. Requires Helm 3 and PyYAML (pip install pyyaml)."""
+import json
+import os
+from pathlib import Path
+import subprocess
+import unittest
+
+CHART = Path(__file__).resolve().parents[1] / 'k8s-cluster/ha-cluster/helm_charts'
+
+def render(overrides=None):
+    command = [os.environ.get('HELM', 'helm'), 'template', 'test', str(CHART)]
+    if overrides:
+        command += ['--values', '-']
+    result = subprocess.run(command, input=json.dumps(overrides or {}),
+                            text=True, encoding='utf-8', capture_output=True, check=True)
+    import yaml
+    return list(yaml.safe_load_all(result.stdout))
+
+def statefulset(documents):
+    return next(doc for doc in documents if doc and doc['kind'] == 'StatefulSet')
+
+class LabelsTest(unittest.TestCase):
+    def test_patroni_matches_pod_labels(self):
+        for overrides in [{}, {'applicationName': 'custom-app', 'clusterName': 'custom-cluster'}]:
+            with self.subTest(overrides=overrides):
+                documents = render(overrides)
+                sts = statefulset(documents)
+                pod = sts['spec']['template']
+                env = {e['name']: e.get('value') for e in pod['spec']['containers'][0]['env']}
+                import yaml
+                labels = yaml.safe_load(env['PATRONI_KUBERNETES_LABELS'])
+                self.assertEqual(labels, pod['metadata']['labels'])
+                self.assertEqual(labels['cluster-name'], env['PATRONI_SCOPE'])
+                for service in documents:
+                    if service and service['kind'] == 'Service':
+                        for key, value in service['spec'].get('selector', {}).items():
+                            if key != 'role':
+                                self.assertEqual(labels[key], value)
+
+if __name__ == '__main__':
+    unittest.main()