[postgresql-ha] Use pgpool service as db connection proxy (#542)

### Description of the change

The `postgresql-ha` provides a dedicated deployment and service called `pgpool`. This application is a proxy that routes the db queries to the active database replica. There's a note about that in their README[^1].

Issue #502 is a side-effect of not using that proxy.

### Possible drawbacks

Using the Charts' default configuration, the `pgpool` deployment has 1 replica, making this a single-point of failure. But users can change the related `postgresql-ha.pgpool.replicaCount` to their needs.

### Applicable issues

- fixes #502

### Checklist

- [x] Templating unittests are added

[^1]: https://github.com/bitnami/charts/blob/main/bitnami/postgresql-ha/templates/postgresql/statefulset.yaml#introduction

Reviewed-on: https://gitea.com/gitea/helm-chart/pulls/542
Reviewed-by: pat-s <pat-s@noreply.gitea.com>
Co-authored-by: justusbunsi <sk.bunsenbrenner@gmail.com>
Co-committed-by: justusbunsi <sk.bunsenbrenner@gmail.com>

templates/_helpers.tpl

@@ -119,7 +119,7 @@ app.kubernetes.io/instance: {{ .Release.Name }}
 
 {{- define "postgresql-ha.dns" -}}
 {{- if (index .Values "postgresql-ha").enabled -}}
-{{- printf "%s-postgresql-ha-postgresql.%s.svc.%s:%g" .Release.Name .Release.Namespace .Values.clusterDomain (index .Values "postgresql-ha" "service" "ports" "postgresql") -}}
+{{- printf "%s-postgresql-ha-pgpool.%s.svc.%s:%g" .Release.Name .Release.Namespace .Values.clusterDomain (index .Values "postgresql-ha" "service" "ports" "postgresql") -}}
 {{- end -}}
 {{- end -}}
 

unittests/config/database-section_postgresql-ha.yaml

@@ -0,0 +1,30 @@
+suite: config template | database section (postgresql-ha)
+release:
+  name: gitea-unittests
+  namespace: testing
+tests:
+  - it: connects to pgpool service
+    template: templates/gitea/config.yaml
+    set:
+      postgresql:
+        enabled: false
+      postgresql-ha:
+        enabled: true
+    asserts:
+      - documentIndex: 0
+        matchRegex:
+          path: stringData.database
+          pattern: HOST=gitea-unittests-postgresql-ha-pgpool.testing.svc.cluster.local:5432
+  - it: renders the referenced service
+    template: charts/postgresql-ha/templates/pgpool/service.yaml
+    set:
+      postgresql:
+        enabled: false
+      postgresql-ha:
+        enabled: true
+    asserts:
+      - containsDocument:
+          kind: Service
+          apiVersion: v1
+          name: gitea-unittests-postgresql-ha-pgpool
+          namespace: testing

unittests/config/database-section_postgresql.yaml

@@ -0,0 +1,30 @@
+suite: config template | database section (postgresql)
+release:
+  name: gitea-unittests
+  namespace: testing
+tests:
+  - it: "connects to postgresql service"
+    template: templates/gitea/config.yaml
+    set:
+      postgresql:
+        enabled: true
+      postgresql-ha:
+        enabled: false
+    asserts:
+      - documentIndex: 0
+        matchRegex:
+          path: stringData.database
+          pattern: HOST=gitea-unittests-postgresql.testing.svc.cluster.local:5432
+  - it: "renders the referenced service"
+    template: charts/postgresql/templates/primary/svc.yaml
+    set:
+      postgresql:
+        enabled: true
+      postgresql-ha:
+        enabled: false
+    asserts:
+      - containsDocument:
+          kind: Service
+          apiVersion: v1
+          name: gitea-unittests-postgresql
+          namespace: testing