feat: implement poddisruptionbudget object creation (#490)

**Description**
poddisruptionbudget objects are rather easy to implement and offer
another unique sellingpoint by being standardised.

**⚙️ Type of change**

- [x] ⚙️ Feature/App addition
- [ ] 🪛 Bugfix
- [ ] ⚠️ Breaking change (fix or feature that would cause existing
functionality to not work as expected)
- [ ] 🔃 Refactor of current code

**🧪 How Has This Been Tested?**
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**📃 Notes:**
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**✔️ Checklist:**

- [ ] ⚖️ My code follows the style guidelines of this project
- [ ] 👀 I have performed a self-review of my own code
- [ ] #️⃣ I have commented my code, particularly in hard-to-understand
areas
- [ ] 📄 I have made corresponding changes to the documentation
- [ ] ⚠️ My changes generate no new warnings
- [ ] 🧪 I have added tests to this description that prove my fix is
effective or that my feature works
- [ ] ⬆️ I increased versions for any altered app according to semantic
versioning

**➕ App addition**

If this PR is an app addition please make sure you have done the
following.

- [ ] 🪞 I have opened a PR on
[truecharts/containers](https://github.com/truecharts/containers) adding
the container to TrueCharts mirror repo.
- [ ] 🖼️ I have added an icon in the Chart's root directory called
`icon.png`

---

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---------

Co-authored-by: Stavros kois <s.kois@outlook.com>

library/common-test/Chart.yaml

@@ -3,7 +3,7 @@ appVersion: ""
 dependencies:
 - name: common
   repository: file://../common
-  version: ~13.0.0
+  version: ~13.1.0
 deprecated: false
 description: Helper chart to test different use cases of the common library
 home: https://github.com/truecharts/apps/tree/master/charts/library/common-test

library/common/Chart.yaml

@@ -15,4 +15,4 @@ maintainers:
 name: common
 sources: null
 type: library
-version: 13.0.1
+version: 13.1.0

library/common/templates/class/_podDisruptionBudget.tpl

@@ -0,0 +1,54 @@
+{{/* poddisruptionbudget Class */}}
+{{/* Call this template:
+{{ include "tc.v1.common.class.podDisruptionBudget" (dict "rootCtx" $ "objectData" $objectData) }}
+
+rootCtx: The root context of the chart.
+objectData:
+  name: The name of the podDisruptionBudget.
+  labels: The labels of the podDisruptionBudget.
+  annotations: The annotations of the podDisruptionBudget.
+  data: The data of the podDisruptionBudget.
+  namespace: The namespace of the podDisruptionBudget. (Optional)
+*/}}
+
+{{- define "tc.v1.common.class.podDisruptionBudget" -}}
+
+  {{- $rootCtx := .rootCtx -}}
+  {{- $objectData := .objectData }}
+---
+apiVersion: policy/v1
+kind: PodDisruptionBudget
+metadata:
+  name: {{ $objectData.name }}
+  namespace: {{ include "tc.v1.common.lib.metadata.namespace" (dict "rootCtx" $rootCtx "objectData" $objectData "caller" "Pod Disruption Budget") }}
+  {{- $labels := (mustMerge ($objectData.labels | default dict) (include "tc.v1.common.lib.metadata.allLabels" $rootCtx | fromYaml)) -}}
+  {{- with (include "tc.v1.common.lib.metadata.render" (dict "rootCtx" $rootCtx "labels" $labels) | trim) }}
+  labels:
+    {{- . | nindent 4 }}
+  {{- end -}}
+  {{- $annotations := (mustMerge ($objectData.annotations | default dict) (include "tc.v1.common.lib.metadata.allAnnotations" $rootCtx | fromYaml)) -}}
+  {{- with (include "tc.v1.common.lib.metadata.render" (dict "rootCtx" $rootCtx "annotations" $annotations) | trim) }}
+  annotations:
+    {{- . | nindent 4 }}
+  {{- end -}}
+data:
+  selector:
+    matchLabels:
+    {{- if $objectData.customLabels -}}
+      {{- with (include "tc.v1.common.lib.metadata.render" (dict "rootCtx" $rootCtx "labels" $objectData.customLabels) | trim) }}
+        {{- . | nindent 6 }}
+      {{- end -}}
+    {{- else -}}
+      {{- $selectedPod := fromJson (include "tc.v1.common.lib.helpers.getSelectedPodValues" (dict "rootCtx" $rootCtx "objectData" $objectData)) }}
+      {{- include "tc.v1.common.lib.metadata.selectorLabels" (dict "rootCtx" $ "objectType" "pod" "objectName" $selectedPod.shortName) | nindent 6 }}
+    {{- end -}}
+  {{- if hasKey "minAvailable" $objectData }}
+  minAvailable: {{ $objectData.minAvailable }}
+  {{- end -}}
+  {{- if hasKey "maxUnavailable" $objectData }}
+  maxUnavailable: {{ $objectData.maxUnavailable }}
+  {{- end -}}
+  {{- with $objectData.unhealthyPodEvictionPolicy }}
+  unhealthyPodEvictionPolicy: {{ . }}
+  {{- end -}}
+{{- end -}}

library/common/templates/lib/podDistruptionBudget/_validation.tpl

@@ -0,0 +1,30 @@
+{{/* Metadata Validation */}}
+{{/* Call this template:
+{{ include "tc.v1.common.lib.podDisruptionBudget.validation" (dict "objectData" $objectData "caller" $caller) -}}
+objectData:
+  labels: The labels of the configmap.
+  annotations: The annotations of the configmap.
+  data: The data of the configmap.
+*/}}
+
+{{- define "tc.v1.common.lib.podDisruptionBudget.validation" -}}
+  {{- $objectData := .objectData -}}
+  {{- $caller := .caller -}}
+
+  {{- with $objectData.unhealthyPodEvictionPolicy -}}
+    {{- $policies := (list "IfHealthyBudget" "AlwaysAllow") -}}
+    {{- if not (mustHas . $policies) -}}
+      {{- fail (printf "Pod Disruption Budget - Expected <unhealthyPodEvictionPolicy> to be one of [%s], but got [%s]" (join ", " $policies) .) -}}
+    {{- end -}}
+  {{- end -}}
+
+  {{- $keys := (list "minAvailable" "maxUnavailable") -}}
+  {{- range $key := $keys -}}
+    {{- if hasKey $key $objectData -}}
+      {{- if kindIs "invalid" (get $objectData $key) -}}
+        {{- fail (printf "Pod Disruption Budget - Expected the defined key [%v] in <podDisruptionBudget.%s> to not be empty" $key $key) -}}
+      {{- end -}}
+    {{- end -}}
+  {{- end -}}
+
+{{- end -}}

library/common/templates/loader/_apply.tpl

@@ -52,6 +52,9 @@
   {{/* Render Networkpolicy(s) */}}
   {{- include "tc.v1.common.spawner.networkpolicy" . | nindent 0 -}}
 
+  {{/* Render podDisruptionBudget(s) */}}
+  {{- include "tc.v1.common.spawner.podDisruptionBudget" . | nindent 0 -}}
+
   {{/* Render Prometheus Metrics(s) */}}
   {{- include "tc.v1.common.spawner.metrics" . | nindent 0 -}}
 

library/common/templates/spawner/_podDisruptionBudget.tpl

@@ -0,0 +1,58 @@
+{{/* poddisruptionbudget Spawwner */}}
+{{/* Call this template:
+{{ include "tc.v1.common.spawner.podDisruptionBudget" $ -}}
+*/}}
+
+{{- define "tc.v1.common.spawner.podDisruptionBudget" -}}
+
+  {{- range $name, $poddisruptionbudget := .Values.podDisruptionBudget -}}
+
+    {{- $enabled := false -}}
+    {{- if hasKey $poddisruptionbudget "enabled" -}}
+      {{- if not (kindIs "invalid" $poddisruptionbudget.enabled) -}}
+        {{- $enabled = $poddisruptionbudget.enabled -}}
+      {{- else -}}
+        {{- fail (printf "Pod Disruption Budget - Expected the defined key [enabled] in <podDisruptionBudget.%s> to not be empty" $name) -}}
+      {{- end -}}
+    {{- end -}}
+
+    {{- if kindIs "string" $enabled -}}
+      {{- $enabled = tpl $enabled $ -}}
+
+      {{/* After tpl it becomes a string, not a bool */}}
+      {{-  if eq $enabled "true" -}}
+        {{- $enabled = true -}}
+      {{- else if eq $enabled "false" -}}
+        {{- $enabled = false -}}
+      {{- end -}}
+    {{- end -}}
+
+    {{- if $enabled -}}
+
+      {{/* Create a copy of the poddisruptionbudget */}}
+      {{- $objectData := (mustDeepCopy $poddisruptionbudget) -}}
+
+      {{- $objectName := (printf "%s-%s" (include "tc.v1.common.lib.chart.names.fullname" $) $name) -}}
+      {{- if hasKey $objectData "expandObjectName" -}}
+        {{- if not $objectData.expandObjectName -}}
+          {{- $objectName = $name -}}
+        {{- end -}}
+      {{- end -}}
+
+      {{/* Perform validations */}}
+      {{- include "tc.v1.common.lib.chart.names.validation" (dict "name" $objectName) -}}
+      {{- include "tc.v1.common.lib.podDisruptionBudget.validation" (dict "objectData" $objectData) -}}
+      {{- include "tc.v1.common.lib.metadata.validation" (dict "objectData" $objectData "caller" "Pod Distruption Budget") -}}
+
+      {{/* Set the name of the poddisruptionbudget */}}
+      {{- $_ := set $objectData "name" $objectName -}}
+      {{- $_ := set $objectData "shortName" $name -}}
+
+      {{/* Call class to create the object */}}
+      {{- include "tc.v1.common.class.podDisruptionBudget" (dict "rootCtx" $ "objectData" $objectData) -}}
+
+    {{- end -}}
+
+  {{- end -}}
+
+{{- end -}}

library/common/values.yaml

@@ -524,6 +524,16 @@ route:
               type: PathPrefix
               value: /
 
+podDisruptionBudget:
+  main:
+    enabled: false
+    # -- Custom Selector Labels
+    # customLabels:
+    #   customKey: customValue
+    targetSelector: main
+    minAvailable: 1
+    maxUnavailable: 1
+
 metrics:
   main:
     enabled: false