Apply tpl() to affinity values to enable reuse of helpers / existing labels (#213)

The Helm tpl function [1] allows to use templates in values. This does make
sense where values might want reference existing labels of a Helm chart.
This is is the case for Pod affinity (or anti-affinity) which needs to match
the labels of the Pods created.

This is somewhat inspired by the way this was done for the NGINX Ingress
Controller with [2].

[1] https://helm.sh/docs/howto/charts_tips_and_tricks/#using-the-tpl-function
[2] af9e5246ad

Resolves: #212

Signed-off-by: Christian Rohmann <christian.rohmann@inovex.de>

charts/qdrant/templates/statefulset.yaml

@@ -199,7 +199,7 @@ spec:
       {{- end }}
       {{- with .Values.affinity }}
       affinity:
-        {{- toYaml . | nindent 8 }}
+        {{- tpl (toYaml .) $ | nindent 8 }}
       {{- end }}
       {{- with .Values.tolerations }}
       tolerations:

charts/qdrant/values.yaml

@@ -121,6 +121,19 @@ nodeSelector: {}
 tolerations: []
 
 affinity: {}
+    # podAntiAffinity:
+    #   requiredDuringSchedulingIgnoredDuringExecution:
+    #   - labelSelector:
+    #       matchExpressions:
+    #         - key: app.kubernetes.io/name
+    #           operator: In
+    #           values:
+    #             - '{{ include "qdrant.name" . }}'
+    #         - key: app.kubernetes.io/instance
+    #           operator: In
+    #           values:
+    #             - '{{ .Release.Name }}'
+    #     topologyKey: "kubernetes.io/hostname"
 
 topologySpreadConstraints: []