[postgres] Restrict password change for user postgres (#1164)

Restrict password change for user postgres

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Chores**
  * Updated the chart version for Postgres from 0.16.0 to 0.17.0.
* Updated the versions map to reference the latest commit and added the
new version.

* **Bug Fixes**
* Enhanced initialization script to forbid creating a user named
"postgres," providing clear error messaging.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/apps/postgres/Chart.yaml

@@ -16,7 +16,7 @@ type: application
 # This is the chart version. This version number should be incremented each time you make changes
 # to the chart and its templates, including the app version.
 # Versions are expected to follow Semantic Versioning (https://semver.org/)
-version: 0.16.0
+version: 0.17.0
 
 # This is the version number of the application being deployed. This version number should be
 # incremented each time you make changes to the application. Versions are not expected to

packages/apps/postgres/templates/init-script.yaml

@@ -38,7 +38,7 @@ stringData:
     until pg_isready ; do sleep 5; done
 
     echo "== create users"
-    {{- if .Values.users }}
+    {{- if and .Values.users (not (hasKey .Values.users "postgres")) }}
     psql -v ON_ERROR_STOP=1 <<\EOT
     {{- range $user, $u := .Values.users }}
     SELECT 'CREATE ROLE "{{ $user }}" LOGIN INHERIT;'
@@ -47,6 +47,8 @@ stringData:
     COMMENT ON ROLE "{{ $user }}" IS 'user managed by helm';
     {{- end }}
     EOT
+    {{- else if and .Values.users (hasKey .Values.users "postgres") }}
+    {{- fail "`users.postgres` is forbidden by policy. Use a different username." }}
     {{- end }}
 
     echo "== delete users"

packages/apps/versions_map

@@ -102,7 +102,8 @@ postgres 0.12.0 6130f43d
 postgres 0.12.1 632224a3
 postgres 0.14.0 62cb694d
 postgres 0.15.1 4369b031
-postgres 0.16.0 HEAD
+postgres 0.16.0 70f82667
+postgres 0.17.0 HEAD
 rabbitmq 0.1.0 263e47be
 rabbitmq 0.2.0 53f2365e
 rabbitmq 0.3.0 6c5cf5bf