fix(deployment): define annotations to automatically roll deployments

The following patch extends the chart to automatically roll the deployment, when
one of the configurations, stored in a config map or secret, has been changed.

The implementation add annotations which triggers `helm update` or ArgoCD to
roll the deployment. Further information can be found on the official helm
website:

  https://helm.sh/docs/howto/charts_tips_and_tricks/#automatically-roll-deployments

templates/prometheus-postgres-exporter/_deployment.tpl

@@ -7,37 +7,6 @@
 {{- if .Values.deployment.annotations }}
 {{ toYaml .Values.deployment.annotations }}
 {{- end }}
-
-# The following annotations are required to trigger a rolling update. Further information can be found in the official
-# documentation of helm:
-#
-#   https://helm.sh/docs/howto/charts_tips_and_tricks/#automatically-roll-deployments
-#
-
-{{/* database */}}
-{{- if and .Values.config.database.existingSecret.enabled .Values.config.database.existingSecret.secretName }}
-{{- $secret := default (dict "data" (dict)) (lookup "v1" "Secret" .Release.Namespace .Values.config.database.existingSecret.secretName ) }}
-checksum/secret-database: {{ print $secret.spec | sha256sum }}
-{{- else }}
-checksum/secret-database: {{ include (print $.Template.BasePath "/prometheus-postgres-exporter/secretDatabase.yaml") . | sha256sum }}
-{{- end }}
-
-{{/* exporter config */}}
-{{- if and .Values.config.exporterConfig.existingSecret.enabled .Values.config.exporterConfig.existingSecret.secretName }}
-{{- $secret := default (dict "data" (dict)) (lookup "v1" "Secret" .Release.Namespace .Values.config.exporterConfig.existingSecret.secretName ) }}
-checksum/secret-exporter-config: {{ print $secret.spec | sha256sum }}
-{{- else }}
-checksum/secret-exporter-config: {{ include (print $.Template.BasePath "/prometheus-postgres-exporter/secretExporterConfig.yaml") . | sha256sum }}
-{{- end }}
-
-{{/* web config */}}
-{{- if and .Values.config.webConfig.existingSecret.enabled .Values.config.webConfig.existingSecret.secretName }}
-{{- $secret := default (dict "data" (dict)) (lookup "v1" "Secret" .Release.Namespace .Values.config.webConfig.existingSecret.secretName ) }}
-checksum/secret-web-config: {{ print $secret.spec | sha256sum }}
-{{- else }}
-checksum/secret-web-config: {{ include (print $.Template.BasePath "/prometheus-postgres-exporter/secretWebConfig.yaml") . | sha256sum }}
-{{- end }}
-
 {{- end }}
 
 {{/* env */}}

templates/prometheus-postgres-exporter/_pod.tpl

@@ -4,6 +4,37 @@
 
 {{- define "prometheus-postgres-exporter.pod.annotations" -}}
 {{ include "prometheus-postgres-exporter.annotations" . }}
+
+# The following annotations are required to trigger a rolling update. Further information can be found in the official
+# documentation of helm:
+#
+#   https://helm.sh/docs/howto/charts_tips_and_tricks/#automatically-roll-deployments
+#
+
+{{/* database */}}
+{{- if and .Values.config.database.existingSecret.enabled .Values.config.database.existingSecret.secretName }}
+{{- $secret := default (dict "data" (dict)) (lookup "v1" "Secret" .Release.Namespace .Values.config.database.existingSecret.secretName ) }}
+checksum/secret-database: {{ print $secret.spec | sha256sum }}
+{{- else }}
+checksum/secret-database: {{ include (print $.Template.BasePath "/prometheus-postgres-exporter/secretDatabase.yaml") . | sha256sum }}
+{{- end }}
+
+{{/* exporter config */}}
+{{- if and .Values.config.exporterConfig.existingSecret.enabled .Values.config.exporterConfig.existingSecret.secretName }}
+{{- $secret := default (dict "data" (dict)) (lookup "v1" "Secret" .Release.Namespace .Values.config.exporterConfig.existingSecret.secretName ) }}
+checksum/secret-exporter-config: {{ print $secret.spec | sha256sum }}
+{{- else }}
+checksum/secret-exporter-config: {{ include (print $.Template.BasePath "/prometheus-postgres-exporter/secretExporterConfig.yaml") . | sha256sum }}
+{{- end }}
+
+{{/* web config */}}
+{{- if and .Values.config.webConfig.existingSecret.enabled .Values.config.webConfig.existingSecret.secretName }}
+{{- $secret := default (dict "data" (dict)) (lookup "v1" "Secret" .Release.Namespace .Values.config.webConfig.existingSecret.secretName ) }}
+checksum/secret-web-config: {{ print $secret.spec | sha256sum }}
+{{- else }}
+checksum/secret-web-config: {{ include (print $.Template.BasePath "/prometheus-postgres-exporter/secretWebConfig.yaml") . | sha256sum }}
+{{- end }}
+
 {{- end }}
 
 {{/* labels */}}

templates/prometheus-postgres-exporter/deployment.yaml

@@ -18,6 +18,8 @@ spec:
       {{- include "prometheus-postgres-exporter.pod.selectorLabels" . | nindent 6 }}
   template:
     metadata:
+      annotations:
+        {{- include "prometheus-postgres-exporter.pod.annotations" . | nindent 8 }}
       labels:
         {{- include "prometheus-postgres-exporter.pod.labels" . | nindent 8 }}
     spec:

unittests/deployment/deployment.yaml

@@ -27,15 +27,9 @@ tests:
       name: prometheus-postgres-exporter-unittest
       namespace: testing
     template: templates/prometheus-postgres-exporter/deployment.yaml
-  - exists:
+  - notExists:
       path: metadata.annotations.checksum/secret-database
     template: templates/prometheus-postgres-exporter/deployment.yaml
-  - exists:
-      path: metadata.annotations.checksum/secret-exporter-config
-    template: templates/prometheus-postgres-exporter/deployment.yaml
-  - exists:
-      path: metadata.annotations.checksum/secret-web-config
-    template: templates/prometheus-postgres-exporter/deployment.yaml
   - equal:
       path: metadata.labels
       value:
@@ -49,6 +43,24 @@ tests:
       path: spec.replicas
       value: 1
     template: templates/prometheus-postgres-exporter/deployment.yaml
+  - exists:
+      path: spec.template.metadata.annotations.checksum/secret-database
+    template: templates/prometheus-postgres-exporter/deployment.yaml
+  - exists:
+      path: spec.template.metadata.annotations.checksum/secret-exporter-config
+    template: templates/prometheus-postgres-exporter/deployment.yaml
+  - exists:
+      path: spec.template.metadata.annotations.checksum/secret-web-config
+    template: templates/prometheus-postgres-exporter/deployment.yaml
+  - equal:
+      path: spec.template.metadata.labels
+      value:
+        app.kubernetes.io/instance: prometheus-postgres-exporter-unittest
+        app.kubernetes.io/managed-by: Helm
+        app.kubernetes.io/name: prometheus-postgres-exporter
+        app.kubernetes.io/version: 0.1.0
+        helm.sh/chart: prometheus-postgres-exporter-0.1.0
+    template: templates/prometheus-postgres-exporter/deployment.yaml
   - notExists:
       path: spec.template.spec.affinity
     template: templates/prometheus-postgres-exporter/deployment.yaml