Helm — Kubernetes Package Engineering

apiVersion: v2
name: my-api-chart
description: "A production-grade Node.js API Helm chart"
type: application
version: 1.0.0        # Chart release version (SemVer)
appVersion: "2.3.1"    # Application version inside the image
keywords:
  - nodejs
  - api
  - microservice
maintainers:
  - name: DevOps Architect
    email: devops@company.com
dependencies:
  - name: postgresql
    version: 12.1.0
    repository: https://charts.bitnami.com/bitnami
    condition: postgresql.enabled   # Only install if flag is true

# ── Replica Settings ──────────────────────────────
replicaCount: 2

# ── Image Configuration ───────────────────────────
image:
  repository: my-registry/my-api
  pullPolicy: IfNotPresent
  tag: ""    # Defaults to Chart appVersion if empty

# ── Service Account ────────────────────────────────
serviceAccount:
  create: true
  annotations: {}
  name: ""

# ── Service ────────────────────────────────────────
service:
  type: ClusterIP
  port: 3000

# ── Ingress ────────────────────────────────────────
ingress:
  enabled: false
  className: "nginx"
  annotations: {}
  hosts:
    - host: api.example.com
      paths: [{ path: /, pathType: Prefix }]

# ── Resource Limits ────────────────────────────────
resources:
  requests: { cpu: 100m, memory: 128Mi }
  limits:   { cpu: 500m, memory: 256Mi }

# ── Autoscaling ────────────────────────────────────
autoscaling:
  enabled: false
  minReplicas: 2
  maxReplicas: 10
  targetCPUUtilizationPercentage: 80

# ── Database Connection ────────────────────────────
dbConnection:
  host: "postgres-svc"
  port: 5432
  name: "myapp_db"
  username: "app_user"
  passwordSecretName: "db-credentials"
  passwordSecretKey: "password"

# ── PostgreSQL Subchart ─────────────────────────────
postgresql:
  enabled: false   # Set true for local dev

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "type": "object",
  "required": ["replicaCount", "image", "service", "dbConnection"],
  "properties": {
    "replicaCount": {
      "type": "integer",
      "minimum": 1,
      "maximum": 50
    },
    "image": {
      "type": "object",
      "required": ["repository", "pullPolicy"],
      "properties": {
        "repository": { "type": "string" },
        "pullPolicy": {
          "type": "string",
          "enum": ["Always", "IfNotPresent", "Never"]
        },
        "tag": { "type": "string" }
      }
    },
    "service": {
      "type": "object",
      "properties": {
        "type": {
          "type": "string",
          "enum": ["ClusterIP", "NodePort", "LoadBalancer"]
        },
        "port": { "type": "integer", "minimum": 1, "maximum": 65535 }
      }
    },
    "dbConnection": {
      "type": "object",
      "required": ["host", "port", "name", "username"],
      "properties": {
        "host":     { "type": "string" },
        "port":     { "type": "integer", "minimum": 1 },
        "name":     { "type": "string" },
        "username": { "type": "string" }
      }
    }
  }
}

{{/* ── Chart Name ─────────────────────────────── */}}
{{- define "my-api-chart.name" -}}
{{- default .Chart.Name .Values.nameOverride | trunc 63 | trimSuffix "-" -}}
{{- end }}

{{/* ── Fully Qualified App Name (max 63 chars) ─── */}}
{{- define "my-api-chart.fullname" -}}
{{- if .Values.fullnameOverride -}}
{{- .Values.fullnameOverride | trunc 63 | trimSuffix "-" -}}
{{- else -}}
{{- $name := default .Chart.Name .Values.nameOverride -}}
{{- if contains $name .Release.Name -}}
{{- .Release.Name | trunc 63 | trimSuffix "-" -}}
{{- else -}}
{{- printf "%s-%s" .Release.Name $name | trunc 63 | trimSuffix "-" -}}
{{- end -}}
{{- end -}}
{{- end }}

{{/* ── Standard Labels ─────────────────────────── */}}
{{- define "my-api-chart.labels" -}}
helm.sh/chart: {{ printf "%s-%s" .Chart.Name .Chart.Version | replace "+" "_" | trunc 63 }}
{{ include "my-api-chart.selectorLabels" . }}
{{- if .Chart.AppVersion }}
app.kubernetes.io/version: {{ .Chart.AppVersion | quote }}
{{- end }}
app.kubernetes.io/managed-by: {{ .Release.Service }}
{{- end }}

{{/* ── Selector Labels ─────────────────────────── */}}
{{- define "my-api-chart.selectorLabels" -}}
app.kubernetes.io/name: {{ include "my-api-chart.name" . }}
app.kubernetes.io/instance: {{ .Release.Name }}
{{- end }}

{{/* ── Service Account Name ───────────────────── */}}
{{- define "my-api-chart.serviceAccountName" -}}
{{- if .Values.serviceAccount.create -}}
{{- default (include "my-api-chart.fullname" .) .Values.serviceAccount.name -}}
{{- else -}}
{{- default "default" .Values.serviceAccount.name -}}
{{- end -}}
{{- end }}

apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ include "my-api-chart.fullname" . }}
  labels:
    {{- include "my-api-chart.labels" . | nindent 4 }}
spec:
  {{- if not .Values.autoscaling.enabled }}
  replicas: {{ .Values.replicaCount }}
  {{- end }}
  selector:
    matchLabels:
      {{- include "my-api-chart.selectorLabels" . | nindent 6 }}
  template:
    metadata:
      labels:
        {{- include "my-api-chart.selectorLabels" . | nindent 8 }}
    spec:
      serviceAccountName: {{ include "my-api-chart.serviceAccountName" . }}
      securityContext:
        runAsNonRoot: true
        runAsUser: 1000
        fsGroup: 2000
      containers:
        - name: {{ .Chart.Name }}
          image: "{{ .Values.image.repository }}:{{ .Values.image.tag | default .Chart.AppVersion }}"
          imagePullPolicy: {{ .Values.image.pullPolicy }}
          ports:
            - name: http
              containerPort: {{ .Values.service.port }}
          env:
            - name: DB_HOST
              value: {{ .Values.dbConnection.host | quote }}
            - name: DB_PORT
              value: {{ .Values.dbConnection.port | quote }}
            - name: DB_PASSWORD
              valueFrom:
                secretKeyRef:
                  name: {{ .Values.dbConnection.passwordSecretName | quote }}
                  key:  {{ .Values.dbConnection.passwordSecretKey | quote }}
          resources:
            {{- toYaml .Values.resources | nindent 12 }}
          readinessProbe:
            httpGet: { path: /health, port: http }
            initialDelaySeconds: 5
          livenessProbe:
            httpGet: { path: /health, port: http }
            initialDelaySeconds: 15

apiVersion: batch/v1
kind: Job
metadata:
  name: "{{ include "my-api-chart.fullname" . }}-db-migrate"
  annotations:
    # This runs BEFORE install AND upgrade
    "helm.sh/hook":               pre-install,pre-upgrade
    "helm.sh/hook-weight":        "5"
    "helm.sh/hook-delete-policy": before-hook-creation,hook-succeeded
spec:
  backoffLimit: 3
  template:
    spec:
      restartPolicy: Never
      containers:
        - name: db-migrator
          image: "{{ .Values.image.repository }}:{{ .Values.image.tag | default .Chart.AppVersion }}"
          command: ["node", "scripts/migrate.js"]
          env:
            - name: DB_HOST
              value: {{ .Values.dbConnection.host | quote }}
            - name: DB_NAME
              value: {{ .Values.dbConnection.name | quote }}
            - name: DB_PASSWORD
              valueFrom:
                secretKeyRef:
                  name: {{ .Values.dbConnection.passwordSecretName | quote }}
                  key:  {{ .Values.dbConnection.passwordSecretKey | quote }}