From 9aecdacf39e829a635e3fbe6ce61001d0fd569ee Mon Sep 17 00:00:00 2001
From: Chi-En Wu <jason.wu@hahow.in>
Date: Wed, 22 Apr 2020 10:26:17 +0800
Subject: [PATCH] feat: allow arguments to be passed to templates

---
 templates/_configmap.yaml             |  5 ++--
 templates/_container.yaml             | 15 ++++++-----
 templates/_cronjob.yaml               | 19 ++++++++------
 templates/_deployment.yaml            | 14 +++++-----
 templates/_hpa.yaml                   | 23 +++++++---------
 templates/_ingress.yaml               | 30 ++++++++++-----------
 templates/_metadata.tpl               |  7 ++---
 templates/_pdb.yaml                   | 31 ++++++++++------------
 templates/_pod.tpl                    | 18 +++++++------
 templates/_secret.yaml                |  5 ++--
 templates/_service.yaml               | 12 +++++----
 templates/_serviceaccount.yaml        | 16 +++++------
 templates/_servicemonitor-secret.yaml | 16 +++++------
 templates/_servicemonitor.yaml        | 31 +++++++++++-----------
 templates/_utils.tpl                  | 38 ++++++++++-----------------
 15 files changed, 137 insertions(+), 143 deletions(-)

diff --git a/templates/_configmap.yaml b/templates/_configmap.yaml
index 05f70f0..d509ada 100644
--- a/templates/_configmap.yaml
+++ b/templates/_configmap.yaml
@@ -1,13 +1,14 @@
 {{/* vim: set filetype=mustache: */}}
 
 {{- define "common.configMap.tpl" -}}
+{{- $top := first . -}}
 apiVersion: v1
 kind: ConfigMap
 metadata:
-  {{ include "common.metadata" . | nindent 2 }}
+  {{ include "common.metadata" (list $top) | nindent 2 }}
 data: {}
 {{- end -}}
 
 {{- define "common.configMap" -}}
-{{- include "common.utils.flattenCall" (list "common.utils.merge" . "common.configMap.tpl") -}}
+{{- include "common.utils.merge" (append . "common.configMap.tpl") -}}
 {{- end -}}
diff --git a/templates/_container.yaml b/templates/_container.yaml
index 32e1fe0..a012156 100644
--- a/templates/_container.yaml
+++ b/templates/_container.yaml
@@ -1,15 +1,18 @@
 {{/* vim: set filetype=mustache: */}}
 
 {{- define "common.container.tpl" -}}
-name: {{ .Chart.Name }}
+{{- $top := first . -}}
+{{- $container := index . 1 -}}
+{{- $image := $container.image | default (dict) -}}
+name: {{ $top.Chart.Name }}
 securityContext:
-  {{- toYaml .Values.securityContext | nindent 4 }}
-image: "{{ .Values.image.repository }}:{{ .Values.image.tag | default .Chart.AppVersion }}"
-imagePullPolicy: {{ .Values.image.pullPolicy }}
+  {{- toYaml $container.securityContext | nindent 4 }}
+image: "{{ $image.repository }}:{{ $image.tag | default $top.Chart.AppVersion }}"
+imagePullPolicy: {{ $container.image.pullPolicy }}
 resources:
-  {{- toYaml .Values.resources | nindent 4 }}
+  {{- toYaml $container.resources | nindent 4 }}
 {{- end -}}
 
 {{- define "common.container" -}}
-{{- include "common.utils.flattenCall" (list "common.utils.merge" . "common.container.tpl") -}}
+{{- include "common.utils.merge" (append . "common.container.tpl") -}}
 {{- end -}}
diff --git a/templates/_cronjob.yaml b/templates/_cronjob.yaml
index c5c6651..2c6eb32 100644
--- a/templates/_cronjob.yaml
+++ b/templates/_cronjob.yaml
@@ -6,29 +6,32 @@ spec:
 {{- end -}}
 
 {{- define "common.cronJob.tpl" -}}
+{{- $top := first . -}}
+{{- $cronJob := index . 1 -}}
+{{- $pod := index . 2 -}}
 apiVersion: batch/v1beta1
 kind: CronJob
 metadata:
-  {{ include "common.metadata" . | nindent 2 }}
+  {{ include "common.metadata" (list $top) | nindent 2 }}
 spec:
-  schedule: "{{ .Values.cronJob.schedule }}"
-  {{- with .Values.cronJob.concurrencyPolicy }}
+  schedule: "{{ $cronJob.schedule }}"
+  {{- with $cronJob.concurrencyPolicy }}
   concurrencyPolicy: {{ . }}
   {{- end }}
-  {{- with .Values.cronJob.failedJobsHistoryLimit }}
+  {{- with $cronJob.failedJobsHistoryLimit }}
   failedJobsHistoryLimit: {{ . }}
   {{- end }}
-  {{- with .Values.cronJob.successfulJobsHistoryLimit }}
+  {{- with $cronJob.successfulJobsHistoryLimit }}
   successfulJobsHistoryLimit: {{ . }}
   {{- end }}
   jobTemplate:
     metadata:
-      {{ include "common.metadata" . | nindent 6 }}
+      {{ include "common.metadata" (list $top) | nindent 6 }}
     spec:
       template:
-        {{ include "common.pod-template" (list . "common.cronJob.pod") | nindent 8 }}
+        {{ include "common.pod-template" (list $top $pod "common.cronJob.pod") | nindent 8 }}
 {{- end -}}
 
 {{- define "common.cronJob" -}}
-{{- include "common.utils.flattenCall" (list "common.utils.merge" . "common.cronJob.tpl") -}}
+{{- include "common.utils.merge" (append . "common.cronJob.tpl") -}}
 {{- end -}}
diff --git a/templates/_deployment.yaml b/templates/_deployment.yaml
index 5f4e448..bcc58a1 100644
--- a/templates/_deployment.yaml
+++ b/templates/_deployment.yaml
@@ -1,22 +1,24 @@
 {{/* vim: set filetype=mustache: */}}
 
 {{- define "common.deployment.tpl" -}}
-{{- $autoscaling := .Values.autoscaling | default (dict) -}}
+{{- $top := first . -}}
+{{- $deployment := index . 1 -}}
+{{- $autoscaling := index . 2 -}}
 apiVersion: apps/v1
 kind: Deployment
 metadata:
-  {{ include "common.metadata" . | nindent 2 }}
+  {{ include "common.metadata" (list $top) | nindent 2 }}
 spec:
   {{- if not $autoscaling.enabled }}
-  replicas: {{ .Values.replicaCount | default 1 }}
+  replicas: {{ $deployment.replicaCount | default 1 }}
   {{- end }}
   selector:
     matchLabels:
-      {{- include "common.selectorLabels" . | nindent 6 }}
+      {{ include "common.selectorLabels" $top | nindent 6 }}
   template:
-    {{- include "common.pod-template" . | nindent 4 }}
+    {{ include "common.pod-template" . | nindent 4 }}
 {{- end -}}
 
 {{- define "common.deployment" -}}
-{{- include "common.utils.flattenCall" (list "common.utils.merge" . "common.deployment.tpl") -}}
+{{- include "common.utils.merge" (append . "common.deployment.tpl") -}}
 {{- end -}}
diff --git a/templates/_hpa.yaml b/templates/_hpa.yaml
index c1a2baa..4253f6b 100644
--- a/templates/_hpa.yaml
+++ b/templates/_hpa.yaml
@@ -1,19 +1,21 @@
 {{/* vim: set filetype=mustache: */}}
 
 {{- define "common.hpa.tpl" -}}
+{{- $top := first . -}}
+{{- $autoscaling := index . 1 -}}
 apiVersion: autoscaling/v2beta2
 kind: HorizontalPodAutoscaler
 metadata:
-  {{ include "common.metadata" . | nindent 2 }}
+  {{ include "common.metadata" (list $top) | nindent 2 }}
 spec:
   scaleTargetRef:
     apiVersion: apps/v1
     kind: Deployment
-    name: {{ include "common.fullname" . }}
-  minReplicas: {{ .Values.autoscaling.minReplicas }}
-  maxReplicas: {{ .Values.autoscaling.maxReplicas }}
+    name: {{ include "common.fullname" $top }}
+  minReplicas: {{ $autoscaling.minReplicas }}
+  maxReplicas: {{ $autoscaling.maxReplicas }}
   metrics:
-  {{- with .Values.autoscaling.cpuUtilizationPercentage }}
+  {{- with $autoscaling.cpuUtilizationPercentage }}
     - type: Resource
       resource:
         name: cpu
@@ -21,7 +23,7 @@ spec:
           type: Utilization
           averageUtilization: {{ . }}
   {{- end }}
-  {{- with .Values.autoscaling.memoryUtilizationPercentage }}
+  {{- with $autoscaling.memoryUtilizationPercentage }}
     - type: Resource
       resource:
         name: memory
@@ -31,14 +33,9 @@ spec:
   {{- end -}}
 {{- end -}}
 
-{{- define "common.hpa.if" -}}
-{{- $top := first . -}}
-{{- $autoscaling := $top.Values.autoscaling | default (dict) -}}
+{{- define "common.hpa" -}}
+{{- $autoscaling := index . 1 -}}
 {{- if $autoscaling.enabled -}}
   {{- include "common.utils.merge" (append . "common.hpa.tpl") -}}
 {{- end -}}
 {{- end -}}
-
-{{- define "common.hpa" -}}
-{{- include "common.utils.flattenCall" (list "common.hpa.if" .) -}}
-{{- end -}}
diff --git a/templates/_ingress.yaml b/templates/_ingress.yaml
index d8638a1..731b60a 100644
--- a/templates/_ingress.yaml
+++ b/templates/_ingress.yaml
@@ -1,27 +1,31 @@
 {{/* vim: set filetype=mustache: */}}
 
 {{- define "common.ingress.metadata" -}}
-{{- with .Values.ingress.annotations }}
+{{- $ingress := index . 1 -}}
+{{- with $ingress.annotations }}
 annotations:
   {{- toYaml . | nindent 2 }}
 {{- end }}
 {{- end -}}
 
 {{- define "common.ingress.tpl" -}}
-{{- $fullName := include "common.fullname" . -}}
-{{- $svcPort := .Values.service.port -}}
-{{- if semverCompare ">=1.14-0" .Capabilities.KubeVersion.GitVersion -}}
+{{- $top := first . -}}
+{{- $ingress := index . 1 -}}
+{{- $service := index . 2 -}}
+{{- $fullName := include "common.fullname" $top -}}
+{{- $svcPort := $service.port -}}
+{{- if semverCompare ">=1.14-0" $top.Capabilities.KubeVersion.GitVersion -}}
 apiVersion: networking.k8s.io/v1beta1
 {{- else -}}
 apiVersion: extensions/v1beta1
 {{- end }}
 kind: Ingress
 metadata:
-  {{ include "common.metadata" (list . "common.ingress.metadata") | nindent 2 }}
+  {{ include "common.metadata" (append . "common.ingress.metadata") | nindent 2 }}
 spec:
-{{- if .Values.ingress.tls }}
+{{- if $ingress.tls }}
   tls:
-  {{- range .Values.ingress.tls }}
+  {{- range $ingress.tls }}
     - hosts:
       {{- range .hosts }}
         - {{ . | quote }}
@@ -30,7 +34,7 @@ spec:
   {{- end }}
 {{- end }}
   rules:
-  {{- range .Values.ingress.hosts }}
+  {{- range $ingress.hosts }}
     - host: {{ .host | quote }}
       http:
         paths:
@@ -43,13 +47,9 @@ spec:
   {{- end }}
 {{- end -}}
 
-{{- define "common.ingress.if" -}}
-{{- $top := first . -}}
-{{- if $top.Values.ingress.enabled -}}
+{{- define "common.ingress" -}}
+{{- $ingress := index . 1 -}}
+{{- if $ingress.enabled -}}
   {{- include "common.utils.merge" (append . "common.ingress.tpl") -}}
 {{- end -}}
 {{- end -}}
-
-{{- define "common.ingress" -}}
-{{- include "common.utils.flattenCall" (list "common.ingress.if" .) -}}
-{{- end -}}
diff --git a/templates/_metadata.tpl b/templates/_metadata.tpl
index e20880b..3efe2e8 100644
--- a/templates/_metadata.tpl
+++ b/templates/_metadata.tpl
@@ -21,14 +21,15 @@ app.kubernetes.io/instance: {{ .Release.Name }}
 {{- end -}}
 
 {{ define "common.metadata.tpl" -}}
-name: {{ include "common.fullname" . }}
+{{- $top := first . -}}
+name: {{ include "common.fullname" $top }}
 labels:
-  {{- include "common.labels" . | nindent 2 -}}
+  {{- include "common.labels" $top | nindent 2 -}}
 {{- end -}}
 
 {{- /*
 Create a standard metadata header
 */ -}}
 {{ define "common.metadata" -}}
-{{- include "common.utils.flattenCall" (list "common.utils.merge" . "common.metadata.tpl") -}}
+{{- include "common.utils.merge" (append . "common.metadata.tpl") -}}
 {{- end -}}
diff --git a/templates/_pdb.yaml b/templates/_pdb.yaml
index 21699fe..ee88c8f 100644
--- a/templates/_pdb.yaml
+++ b/templates/_pdb.yaml
@@ -1,35 +1,32 @@
 {{/* vim: set filetype=mustache: */}}
 
 {{- define "common.pdb.tpl" -}}
+{{- $top := first . -}}
+{{- $pdb := index . 1 -}}
 apiVersion: policy/v1beta1
 kind: PodDisruptionBudget
 metadata:
-  {{ include "common.metadata" . | nindent 2 }}
+  {{ include "common.metadata" (list $top) | nindent 2 }}
 spec:
   selector:
     matchLabels:
-      {{- include "common.selectorLabels" . | nindent 6 }}
-  {{- with .Values.podDisruptionBudget }}
-  {{- if not (or (empty .minAvailable) (empty .maxUnavailable)) -}}
-    {{- fail "podDisruptionBudget.minAvailable and podDisruptionBudget.maxUnavailable can not be set together" }}
+      {{- include "common.selectorLabels" $top | nindent 6 }}
+  {{- if not (or (empty $pdb.minAvailable) (empty $pdb.maxUnavailable)) -}}
+    {{- fail "minAvailable and maxUnavailable can not be set together" }}
   {{- end -}}
-  {{- with .minAvailable }}
+  {{- with $pdb.minAvailable }}
   minAvailable: {{ . }}
   {{- end }}
-  {{- with .maxUnavailable }}
+  {{- with $pdb.maxUnavailable }}
   maxUnavailable: {{ . }}
   {{- end }}
-  {{- end }}
-{{- end -}}
-
-{{- define "common.pdb.if" -}}
-{{- $top := first . -}}
-{{- $autoscaling := $top.Values.autoscaling | default (dict) -}}
-{{- if or (and $autoscaling.enabled (gt ($autoscaling.minReplicas | int) 1)) (gt ($top.Values.replicaCount | int) 1) }}
-  {{- include "common.utils.merge" (append . "common.pdb.tpl") -}}
-{{- end -}}
 {{- end -}}
 
 {{- define "common.pdb" -}}
-{{- include "common.utils.flattenCall" (list "common.pdb.if" .) -}}
+{{- $top := first . -}}
+{{- $pod := index . 2 -}}
+{{- $autoscaling := index . 3 -}}
+{{- if or (and $autoscaling.enabled (gt ($autoscaling.minReplicas | int) 1)) (gt ($pod.replicaCount | int) 1) }}
+  {{- include "common.utils.merge" (append . "common.pdb.tpl") -}}
+{{- end -}}
 {{- end -}}
diff --git a/templates/_pod.tpl b/templates/_pod.tpl
index ca2b38d..224b1e3 100644
--- a/templates/_pod.tpl
+++ b/templates/_pod.tpl
@@ -1,33 +1,35 @@
 {{/* vim: set filetype=mustache: */}}
 
 {{- define "common.pod-template.tpl" -}}
+{{- $top := first . -}}
+{{- $values := index . 1 -}}
 metadata:
   labels:
-    {{- include "common.selectorLabels" . | nindent 4 }}
+    {{- include "common.selectorLabels" $top | nindent 4 }}
 spec:
-  {{- with .Values.imagePullSecrets }}
+  {{- with $values.imagePullSecrets }}
   imagePullSecrets:
     {{- toYaml . | nindent 8 }}
   {{- end }}
-  serviceAccountName: {{ include "common.serviceAccountName" . }}
+  serviceAccountName: {{ include "common.serviceAccountName" $top }}
   securityContext:
-    {{- toYaml .Values.podSecurityContext | nindent 4 }}
+    {{- toYaml $values.podSecurityContext | nindent 4 }}
   containers:
     - {{- include "common.container" . | nindent 6 }}
-  {{- with .Values.nodeSelector }}
+  {{- with $values.nodeSelector }}
   nodeSelector:
     {{- toYaml . | nindent 4 }}
   {{- end }}
-  {{- with .Values.affinity }}
+  {{- with $values.affinity }}
   affinity:
     {{- toYaml . | nindent 4 }}
   {{- end }}
-  {{- with .Values.tolerations }}
+  {{- with $values.tolerations }}
   tolerations:
     {{- toYaml . | nindent 4 }}
   {{- end }}
 {{- end -}}
 
 {{- define "common.pod-template" -}}
-{{- include "common.utils.flattenCall" (list "common.utils.merge" . "common.pod-template.tpl") -}}
+{{- include "common.utils.merge" (append . "common.pod-template.tpl") -}}
 {{- end -}}
diff --git a/templates/_secret.yaml b/templates/_secret.yaml
index 37b19f9..0bcbc66 100644
--- a/templates/_secret.yaml
+++ b/templates/_secret.yaml
@@ -1,14 +1,15 @@
 {{/* vim: set filetype=mustache: */}}
 
 {{- define "common.secret.tpl" -}}
+{{- $top := first . -}}
 apiVersion: v1
 kind: Secret
 metadata:
-  {{ include "common.metadata" . | nindent 2 }}
+  {{ include "common.metadata"  (list $top) | nindent 2 }}
 type: Opaque
 data: {}
 {{- end -}}
 
 {{- define "common.secret" -}}
-{{- include "common.utils.flattenCall" (list "common.utils.merge" . "common.secret.tpl") -}}
+{{- include "common.utils.merge" (append . "common.secret.tpl") -}}
 {{- end -}}
diff --git a/templates/_service.yaml b/templates/_service.yaml
index eb3d299..3f151b8 100644
--- a/templates/_service.yaml
+++ b/templates/_service.yaml
@@ -1,21 +1,23 @@
 {{/* vim: set filetype=mustache: */}}
 
 {{- define "common.service.tpl" -}}
+{{- $top := first . -}}
+{{- $service := index . 1 -}}
 apiVersion: v1
 kind: Service
 metadata:
-  {{ include "common.metadata" . | nindent 2 }}
+  {{ include "common.metadata" (list $top) | nindent 2 }}
 spec:
-  type: {{ .Values.service.type }}
+  type: {{ $service.type }}
   ports:
-    - port: {{ .Values.service.port }}
+    - port: {{ $service.port }}
       targetPort: http
       protocol: TCP
       name: http
   selector:
-    {{- include "common.selectorLabels" . | nindent 4 }}
+    {{- include "common.selectorLabels" $top | nindent 4 }}
 {{- end -}}
 
 {{- define "common.service" -}}
-{{- include "common.utils.flattenCall" (list "common.utils.merge" . "common.service.tpl") -}}
+{{- include "common.utils.merge" (append . "common.service.tpl") -}}
 {{- end -}}
diff --git a/templates/_serviceaccount.yaml b/templates/_serviceaccount.yaml
index 8209b09..bd425f0 100644
--- a/templates/_serviceaccount.yaml
+++ b/templates/_serviceaccount.yaml
@@ -1,8 +1,10 @@
 {{/* vim: set filetype=mustache: */}}
 
 {{- define "common.serviceAccount.metadata" -}}
-name: {{ include "common.serviceAccountName" . }}
-{{- with .Values.serviceAccount.annotations }}
+{{- $top := first . -}}
+{{- $serviceAccount := index . 1 -}}
+name: {{ include "common.serviceAccountName" $top }}
+{{- with $serviceAccount.annotations }}
 annotations:
   {{- toYaml . | nindent 2 }}
 {{- end }}
@@ -12,17 +14,13 @@ annotations:
 apiVersion: v1
 kind: ServiceAccount
 metadata:
-  {{ include "common.metadata" (list . "common.serviceAccount.metadata") | nindent 2 }}
+  {{ include "common.metadata" (append . "common.serviceAccount.metadata") | nindent 2 }}
 {{- end -}}
 
-{{- define "common.serviceAccount.if" -}}
+{{- define "common.serviceAccount" -}}
 {{- $top := first . -}}
-{{- $serviceAccount := $top.Values.serviceAccount | default (dict) -}}
+{{- $serviceAccount := index . 1 -}}
 {{- if $serviceAccount.create -}}
   {{- include "common.utils.merge" (append . "common.serviceAccount.tpl") -}}
 {{- end -}}
 {{- end -}}
-
-{{- define "common.serviceAccount" -}}
-{{- include "common.utils.flattenCall" (list "common.serviceAccount.if" .) -}}
-{{- end -}}
diff --git a/templates/_servicemonitor-secret.yaml b/templates/_servicemonitor-secret.yaml
index ec6283e..21f60c6 100644
--- a/templates/_servicemonitor-secret.yaml
+++ b/templates/_servicemonitor-secret.yaml
@@ -1,10 +1,12 @@
 {{/* vim: set filetype=mustache: */}}
 
 {{- define "common.serviceMonitor.secret.tpl" -}}
-{{- $basicAuth := .Values.serviceMonitor.basicAuth | default (dict) -}}
+{{- $top := first . -}}
+{{- $serviceMonitor := index . 1 -}}
+{{- $basicAuth := $serviceMonitor.basicAuth | default (dict) -}}
 metadata:
-  name: {{ $basicAuth.secretName | default (include "common.fullname" .) }}
-  {{- with .Values.serviceMonitor.namespace }}
+  name: {{ $basicAuth.secretName | default (include "common.fullname" $top) }}
+  {{- with $serviceMonitor.namespace }}
   namespace: {{ . }}
   {{- end }}
 {{- if $basicAuth.enabled }}
@@ -14,14 +16,10 @@ data:
 {{- end }}
 {{- end -}}
 
-{{- define "common.serviceMonitor.secret.if" -}}
+{{- define "common.serviceMonitor.secret" -}}
 {{- $top := first . -}}
-{{- $serviceMonitor := $top.Values.serviceMonitor | default (dict) -}}
+{{- $serviceMonitor := index . 1 -}}
 {{- if $serviceMonitor.enabled -}}
   {{- include "common.secret" (append . "common.serviceMonitor.secret.tpl") -}}
 {{- end -}}
 {{- end -}}
-
-{{- define "common.serviceMonitor.secret" -}}
-{{- include "common.utils.flattenCall" (list "common.serviceMonitor.secret.if" .) -}}
-{{- end -}}
diff --git a/templates/_servicemonitor.yaml b/templates/_servicemonitor.yaml
index 91156b1..965a17b 100644
--- a/templates/_servicemonitor.yaml
+++ b/templates/_servicemonitor.yaml
@@ -1,36 +1,39 @@
 {{/* vim: set filetype=mustache: */}}
 
 {{- define "common.serviceMonitor.metadata" -}}
-{{- with .Values.serviceMonitor.namespace }}
+{{- $serviceMonitor := index . 1 -}}
+{{- with $serviceMonitor.namespace }}
 namespace: {{ . }}
 {{- end }}
 {{- end -}}
 
 {{- define "common.serviceMonitor.tpl" -}}
+{{- $top := first . -}}
+{{- $serviceMonitor := index . 1 -}}
 apiVersion: monitoring.coreos.com/v1
 kind: ServiceMonitor
 metadata:
-  {{ include "common.metadata" (list . "common.serviceMonitor.metadata") | nindent 2 }}
+  {{ include "common.metadata" (append . "common.serviceMonitor.metadata") | nindent 2 }}
 spec:
   selector:
     matchLabels:
-      {{- include "common.selectorLabels" . | nindent 6 }}
+      {{- include "common.selectorLabels" $top | nindent 6 }}
   namespaceSelector:
     matchNames:
-    - {{ .Release.Namespace | quote }}
+    - {{ $top.Release.Namespace | quote }}
   endpoints:
-  - port: {{ .Values.serviceMonitor.port | default .Values.service.port }}
-    {{- with .Values.serviceMonitor.path }}
+  - port: {{ $serviceMonitor.port }}
+    {{- with $serviceMonitor.path }}
     path: {{ . }}
     {{- end }}
-    {{- with .Values.serviceMonitor.interval }}
+    {{- with $serviceMonitor.interval }}
     interval: {{ . }}
     {{- end }}
-    {{- with .Values.serviceMonitor.scrapeTimeout }}
+    {{- with $serviceMonitor.scrapeTimeout }}
     scrapeTimeout: {{ . }}
     {{- end }}
-    {{- $basicAuth := .Values.serviceMonitor.basicAuth | default (dict) -}}
-    {{- $name := $basicAuth.secretName | default (include "common.fullname" .) -}}
+    {{- $basicAuth := $serviceMonitor.basicAuth | default (dict) -}}
+    {{- $name := $basicAuth.secretName | default (include "common.fullname" $top) -}}
     {{- if $basicAuth.enabled }}
     basicAuth:
       username:
@@ -42,14 +45,10 @@ spec:
     {{- end }}
 {{- end -}}
 
-{{- define "common.serviceMonitor.if" -}}
+{{- define "common.serviceMonitor" -}}
 {{- $top := first . -}}
-{{- $serviceMonitor := $top.Values.serviceMonitor | default (dict) -}}
+{{- $serviceMonitor := index . 1 -}}
 {{- if $serviceMonitor.enabled -}}
   {{- include "common.utils.merge" (append . "common.serviceMonitor.tpl") -}}
 {{- end -}}
 {{- end -}}
-
-{{- define "common.serviceMonitor" -}}
-{{- include "common.utils.flattenCall" (list "common.serviceMonitor.if" .) -}}
-{{- end -}}
diff --git a/templates/_utils.tpl b/templates/_utils.tpl
index f0c087a..834979c 100644
--- a/templates/_utils.tpl
+++ b/templates/_utils.tpl
@@ -3,32 +3,22 @@
 {{- /*
 Merge one or more YAML templates and output the result.
 This takes an list of values:
-- the first item is the top context
-- the rest items are template names of the templates, the former one will override the latter.
+- the top context
+- [optional] zero or more template args
+- [optional] the template name of the overrides (destination)
+- the template name of the base (source)
 */ -}}
 {{- define "common.utils.merge" -}}
 {{- $top := first . -}}
-{{- $dest := dict -}}
-{{- range (rest .) -}}
-  {{- $src := fromYaml (include . $top) | default (dict) -}}
-  {{- $dest = merge $dest $src -}}
+{{- $tplName := last . -}}
+{{- $args := initial . -}}
+{{- if typeIs "string" (last $args) -}}
+  {{- $overridesName := last $args -}}
+  {{- $args = initial $args -}}
+  {{- $tpl := fromYaml (include $tplName $args) | default (dict) -}}
+  {{- $overrides := fromYaml (include $overridesName $args) | default (dict) -}}
+  {{- toYaml (merge $overrides $tpl) -}}
+{{- else -}}
+  {{- include $tplName $args -}}
 {{- end -}}
-{{- toYaml $dest -}}
-{{- end -}}
-
-{{- /*
-Flatten list of arguments before rendering the given template.
-This takes an list of values:
-- the first item is the template name to be rendered
-- the second item is either an list of arguments or a single argument
-- the rest items are the appended arguments
-*/ -}}
-{{- define "common.utils.flattenCall" -}}
-{{- $tpl := first . -}}
-{{- $args := index . 1 -}}
-{{- if not (typeIs "[]interface {}" $args) -}}
-  {{- $args = list $args -}}
-{{- end -}}
-{{- $args = concat $args (slice . 2) -}}
-{{- include $tpl $args -}}
 {{- end -}}