httpbin: convert to Helm chart

closes: #957

Signed-off-by: knrt10 <kautilya@kinvolk.io>

assets/charts/components/httpbin/.helmignore

@@ -0,0 +1,23 @@
+# Patterns to ignore when building packages.
+# This supports shell glob matching, relative path matching, and
+# negation (prefixed with !). Only one pattern per line.
+.DS_Store
+# Common VCS dirs
+.git/
+.gitignore
+.bzr/
+.bzrignore
+.hg/
+.hgignore
+.svn/
+# Common backup files
+*.swp
+*.bak
+*.tmp
+*.orig
+*~
+# Various IDEs
+.project
+.idea/
+*.tmproj
+.vscode/

assets/charts/components/httpbin/Chart.yaml

@@ -0,0 +1,23 @@
+apiVersion: v2
+name: httpbin
+description: A Helm chart for Kubernetes
+
+# A chart can be either an 'application' or a 'library' chart.
+#
+# Application charts are a collection of templates that can be packaged into versioned archives
+# to be deployed.
+#
+# Library charts provide useful utilities or functions for the chart developer. They're included as
+# a dependency of application charts to inject those utilities and functions into the rendering
+# pipeline. Library charts do not define any templates and therefore cannot be deployed.
+type: application
+
+# This is the chart version. This version number should be incremented each time you make changes
+# to the chart and its templates, including the app version.
+# Versions are expected to follow Semantic Versioning (https://semver.org/)
+version: 0.1.0
+
+# This is the version number of the application being deployed. This version number should be
+# incremented each time you make changes to the application. Versions are not expected to
+# follow Semantic Versioning. They should reflect the version the application is using.
+appVersion: v0.6.1

assets/charts/components/httpbin/templates/deployment.yaml

@@ -0,0 +1,37 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  labels:
+    app: httpbin
+  name: httpbin
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: httpbin
+  strategy:
+    rollingUpdate:
+      maxSurge: 1
+      maxUnavailable: 1
+    type: RollingUpdate
+  template:
+    metadata:
+      labels:
+        app: httpbin
+    spec:
+      containers:
+      - image: docker.io/kennethreitz/httpbin
+        name: httpbin
+        ports:
+        - containerPort: 8080
+          name: http
+        command: ["gunicorn"]
+        args: ["-b", "0.0.0.0:8080", "httpbin:app"]
+      dnsPolicy: ClusterFirst
+      restartPolicy: Always
+      schedulerName: default-scheduler
+      securityContext:
+        runAsNonRoot: true
+        runAsUser: 65534
+        runAsGroup: 65534
+      terminationGracePeriodSeconds: 30

assets/charts/components/httpbin/templates/ingress.yaml

@@ -0,0 +1,20 @@
+apiVersion: networking.k8s.io/v1beta1
+kind: Ingress
+metadata:
+  name: httpbin
+  annotations:
+    kubernetes.io/tls-acme: "true"
+    cert-manager.io/cluster-issuer: {{ .Values.certManagerClusterIssuer }}
+    kubernetes.io/ingress.class: contour
+spec:
+  tls:
+  - secretName: {{ .Values.ingressHost }}-tls
+    hosts:
+    - {{ .Values.ingressHost }}
+  rules:
+  - host: {{ .Values.ingressHost }}
+    http:
+      paths:
+      - backend:
+          serviceName: httpbin
+          servicePort: 8080

assets/charts/components/httpbin/templates/service.yaml

@@ -0,0 +1,11 @@
+apiVersion: v1
+kind: Service
+metadata:
+  name: httpbin
+spec:
+  ports:
+  - port: 8080
+    protocol: TCP
+    targetPort: 8080
+  selector:
+    app: httpbin

assets/charts/components/httpbin/values.yaml

@@ -0,0 +1,2 @@
+certManagerClusterIssuer:
+ingressHost:

pkg/components/httpbin/component.go

@@ -15,109 +15,20 @@
 package httpbin
 
 import (
-	"bytes"
 	"fmt"
-	"text/template"
 
 	"github.com/hashicorp/hcl/v2"
 	"github.com/hashicorp/hcl/v2/gohcl"
 
+	internaltemplate "github.com/kinvolk/lokomotive/internal/template"
 	"github.com/kinvolk/lokomotive/pkg/components"
+	"github.com/kinvolk/lokomotive/pkg/components/util"
 	"github.com/kinvolk/lokomotive/pkg/k8sutil"
 )
 
 const name = "httpbin"
 
-const namespaceManifest = `apiVersion: v1
-kind: Namespace
-metadata:
-  name: httpbin
-  labels:
-    name: httpbin
-`
-
-const deploymentManifest = `apiVersion: apps/v1
-kind: Deployment
-metadata:
-  labels:
-    app: httpbin
-  name: httpbin
-  namespace: httpbin
-spec:
-  replicas: 1
-  selector:
-    matchLabels:
-      app: httpbin
-  strategy:
-    rollingUpdate:
-      maxSurge: 1
-      maxUnavailable: 1
-    type: RollingUpdate
-  template:
-    metadata:
-      labels:
-        app: httpbin
-    spec:
-      containers:
-      - image: docker.io/kennethreitz/httpbin
-        name: httpbin
-        ports:
-        - containerPort: 8080
-          name: http
-        command: ["gunicorn"]
-        args: ["-b", "0.0.0.0:8080", "httpbin:app"]
-      dnsPolicy: ClusterFirst
-      restartPolicy: Always
-      schedulerName: default-scheduler
-      securityContext:
-        runAsNonRoot: true
-        runAsUser: 65534
-        runAsGroup: 65534
-      terminationGracePeriodSeconds: 30
-`
-
-const serviceManifest = `apiVersion: v1
-kind: Service
-metadata:
-  name: httpbin
-  namespace: httpbin
-spec:
-  ports:
-  - port: 8080
-    protocol: TCP
-    targetPort: 8080
-  selector:
-    app: httpbin
-`
-
-const ingressTmpl = `apiVersion: networking.k8s.io/v1beta1
-kind: Ingress
-metadata:
-  name: httpbin
-  namespace: httpbin
-  labels:
-    app.kubernetes.io/managed-by: Helm
-  annotations:
-    kubernetes.io/tls-acme: "true"
-    cert-manager.io/cluster-issuer: {{ .CertManagerClusterIssuer }}
-    kubernetes.io/ingress.class: contour
-    meta.helm.sh/release-name: httpbin
-    meta.helm.sh/release-namespace: httpbin
-spec:
-  tls:
-  - secretName: {{ .IngressHost }}-tls
-    hosts:
-    - {{ .IngressHost }}
-  rules:
-  - host: {{ .IngressHost }}
-    http:
-      paths:
-      - backend:
-          serviceName: httpbin
-          servicePort: 8080
-`
-
-func init() {
+func init() { //nolint:gochecknoinits
 	components.Register(name, newComponent())
 }
 
@@ -138,25 +49,28 @@ func (c *component) LoadConfig(configBody *hcl.Body, evalContext *hcl.EvalContex
 			components.HCLDiagConfigBodyNil,
 		}
 	}
+
 	return gohcl.DecodeBody(*configBody, evalContext, c)
 }
 
-// TODO: Convert to Helm chart.
 func (c *component) RenderManifests() (map[string]string, error) {
-	tmpl, err := template.New("ingress").Parse(ingressTmpl)
+	helmChart, err := components.Chart(name)
 	if err != nil {
-		return nil, fmt.Errorf("parsing template: %w", err)
+		return nil, fmt.Errorf("retrieving chart from assets: %w", err)
 	}
-	var buf bytes.Buffer
-	if err := tmpl.Execute(&buf, c); err != nil {
-		return nil, fmt.Errorf("executing template: %w", err)
+
+	values, err := internaltemplate.Render(chartValuesTmpl, c)
+	if err != nil {
+		return nil, fmt.Errorf("rendering values template failed: %w", err)
 	}
-	return map[string]string{
-		"namespace.yml":  namespaceManifest,
-		"deployment.yml": deploymentManifest,
-		"service.yml":    serviceManifest,
-		"ingress.yml":    buf.String(),
-	}, nil
+
+	// Generate YAML for the httpbin deployment.
+	renderedFiles, err := util.RenderChart(helmChart, name, c.Metadata().Namespace.Name, values)
+	if err != nil {
+		return nil, fmt.Errorf("rendering chart failed: %w", err)
+	}
+
+	return renderedFiles, nil
 }
 
 func (c *component) Metadata() components.Metadata {

pkg/components/httpbin/template.go

@@ -0,0 +1,22 @@
+// Copyright 2020 The Lokomotive Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package httpbin has code related to deployment of httpbin component.
+package httpbin
+
+const chartValuesTmpl = `
+ingressHost: {{ .IngressHost }}
+
+certManagerClusterIssuer: {{ .CertManagerClusterIssuer }}
+`