Extract component versions to a static file

This should make it easier to add new components, or change versions.
Embed the file into the binary with Go Embed.

Signed-off-by: David Calavera <dcalaverapalacio@twilio.com>

cmd/check_versions.go

@@ -2,6 +2,8 @@ package cmd
 
 import (
 	"context"
+	"encoding/json"
+	"fmt"
 	"os"
 	"strings"
 
@@ -12,6 +14,8 @@ import (
 	"k8s.io/cli-runtime/pkg/printers"
 	"k8s.io/client-go/kubernetes"
 
+	_ "embed"
+
 	"github.com/blang/semver/v4"
 )
 
@@ -49,22 +53,8 @@ type Services []Service
 // that can be used for reference
 type KubernetesVersions map[string]Services
 
-// This is the source of truth for what versions
-// belong on which servers
-var (
-	versions = KubernetesVersions{
-		"v1.19": Services{
-			{Name: "cert-manager", Version: "1.4.0"},
-			{Name: "coredns", Version: "1.8.4"},
-			{Name: "kube-proxy", Version: "1.19.6-eksbuild.2"},
-			{Name: "kube-state-metrics", Version: "2.1.0"},
-			{Name: "metrics-server", Version: "0.5.0"},
-			{Name: "node-problem-detector", Version: "0.8.9"},
-			{Name: "nvidia-device-plugin", Version: "0.9.0"},
-			{Name: "cluster-autoscaler", Version: "1.19"},
-		},
-	}
-)
+//go:embed config/components.json
+var componentsConfig []byte
 
 var getVersionsCmd = &cobra.Command{
 	Use:   "versions",
@@ -92,7 +82,10 @@ var getVersionsCmd = &cobra.Command{
 		for _, s := range svcs {
 			// walk through required versions and
 			// find the matching service
-			req := getRequiredVersion(kubeVersion, s.Name)
+			req, err := getRequiredVersion(kubeVersion, s.Name)
+			if err != nil {
+				return err
+			}
 			if req == "unknown" {
 				continue
 			}
@@ -128,13 +121,17 @@ func isOutOfDate(required, current string) (bool, error) {
 	return r.Compare(c) > 0, nil
 }
 
-func getRequiredVersion(kubernetesVersion string, serviceName string) string {
+func getRequiredVersion(kubernetesVersion string, serviceName string) (string, error) {
+	var versions KubernetesVersions
+	if err := json.Unmarshal(componentsConfig, &versions); err != nil {
+		return "", fmt.Errorf("unable to read components configuration: %w", err)
+	}
 	for _, e := range versions[kubernetesVersion] {
 		if e.Name == serviceName {
-			return e.Version
+			return e.Version, nil
 		}
 	}
-	return "unknown"
+	return "unknown", nil
 }
 
 func getDeployments(clientset *kubernetes.Clientset, namespace string) (Services, error) {

cmd/check_versions_test.go

@@ -0,0 +1,55 @@
+package cmd
+
+import "testing"
+
+func TestGetRequiredVersions(t *testing.T) {
+	cases := Services{
+		{
+			Name:    "cert-manager",
+			Version: "1.4.0",
+		},
+		{
+			Name:    "coredns",
+			Version: "1.8.4",
+		},
+		{
+			Name:    "kube-proxy",
+			Version: "1.19.6-eksbuild.2",
+		},
+		{
+			Name:    "kube-state-metrics",
+			Version: "2.1.0",
+		},
+		{
+			Name:    "metrics-server",
+			Version: "0.5.0",
+		},
+		{
+			Name:    "node-problem-detector",
+			Version: "0.8.9",
+		},
+		{
+			Name:    "nvidia-device-plugin",
+			Version: "0.9.0",
+		},
+		{
+			Name:    "cluster-autoscaler",
+			Version: "1.19",
+		},
+	}
+
+	for _, test := range cases {
+		actual, err := getRequiredVersion("v1.19", test.Name)
+		if err != nil {
+			t.Fatal(err)
+		}
+		assertVersion(t, test.Name, test.Version, actual)
+	}
+}
+
+func assertVersion(t *testing.T, component, expected, actual string) {
+	t.Helper()
+	if expected != actual {
+		t.Fatalf("expected %s version %s, got %s", component, expected, actual)
+	}
+}

cmd/config/components.json

@@ -0,0 +1,36 @@
+{
+    "v1.19": [
+        {
+            "Name": "cert-manager",
+            "Version": "1.4.0"
+        },
+        {
+            "Name": "coredns",
+            "Version": "1.8.4"
+        },
+        {
+            "Name": "kube-proxy",
+            "Version": "1.19.6-eksbuild.2"
+        },
+        {
+            "Name": "kube-state-metrics",
+            "Version": "2.1.0"
+        },
+        {
+            "Name": "metrics-server",
+            "Version": "0.5.0"
+        },
+        {
+            "Name": "node-problem-detector",
+            "Version": "0.8.9"
+        },
+        {
+            "Name": "nvidia-device-plugin",
+            "Version": "0.9.0"
+        },
+        {
+            "Name": "cluster-autoscaler",
+            "Version": "1.19"
+        }
+    ]
+}