pkg/components/util: refactor InstallComponent to make it shorter

This commit moves ensuring that release namespace exists code into
separate function, so linter does not complain about function length and
potentially allows to test this bit of code independently.

Signed-off-by: Mateusz Gozdek <mateusz@kinvolk.io>

Author: invidian

pkg/components/util/install.go

@@ -19,6 +19,7 @@ import (
 	"fmt"
 
 	"helm.sh/helm/v3/pkg/action"
+	"helm.sh/helm/v3/pkg/chart"
 	"helm.sh/helm/v3/pkg/kube"
 	"helm.sh/helm/v3/pkg/storage/driver"
 	v1 "k8s.io/api/core/v1"
@@ -29,31 +30,38 @@ import (
 	"github.com/kinvolk/lokomotive/pkg/k8sutil"
 )
 
-// InstallComponent installs given component using given kubeconfig as a Helm release using a Helm client.
-func InstallComponent(c components.Component, kubeconfig string) error {
-	name := c.Metadata().Name
-
-	cs, err := k8sutil.NewClientset(kubeconfig)
+func ensureNamespaceExists(name string, kubeconfigPath string) error {
+	cs, err := k8sutil.NewClientset(kubeconfigPath)
 	if err != nil {
-		return err
+		return fmt.Errorf("creating clientset: %w", err)
 	}
 
-	// Get the namespace in which the component should be created.
-	ns := c.Metadata().Namespace
-	if ns == "" {
-		return fmt.Errorf("component %s namespace is empty", name)
+	if name == "" {
+		return fmt.Errorf("namespace name can't be empty")
 	}
 
 	// Ensure the namespace in which we create release and resources exists.
 	_, err = cs.CoreV1().Namespaces().Create(context.TODO(), &v1.Namespace{
 		ObjectMeta: metav1.ObjectMeta{
-			Name: ns,
+			Name: name,
 		},
 	}, metav1.CreateOptions{})
 	if err != nil && !errors.IsAlreadyExists(err) {
 		return err
 	}
 
+	return nil
+}
+
+// InstallComponent installs given component using given kubeconfig as a Helm release using a Helm client.
+func InstallComponent(c components.Component, kubeconfig string) error {
+	name := c.Metadata().Name
+	ns := c.Metadata().Namespace
+
+	if err := ensureNamespaceExists(ns, kubeconfig); err != nil {
+		return fmt.Errorf("failed ensuring that namespace %q for component %q exists: %w", ns, name, err)
+	}
+
 	actionConfig, err := HelmActionConfig(ns, kubeconfig)
 	if err != nil {
 		return fmt.Errorf("failed preparing helm client: %w", err)
@@ -75,37 +83,59 @@ func InstallComponent(c components.Component, kubeconfig string) error {
 
 	wait := c.Metadata().Helm.Wait
 
+	helmAction := &helmAction{
+		releaseName:  name,
+		chart:        chart,
+		actionConfig: actionConfig,
+		wait:         wait,
+	}
+
 	if !exists {
-		install := action.NewInstall(actionConfig)
-		install.ReleaseName = name
-		install.Namespace = ns
-
-		// Currently, we install components one-by-one, in the order how they are
-		// defined in the configuration and we do not support any dependencies between
-		// the components.
-		//
-		// If it is critical for component to have it's dependencies ready before it is
-		// installed, all dependencies should set Wait field to 'true' in components.HelmMetadata
-		// struct.
-		//
-		// The example of such dependency is between prometheus-operator and openebs-storage-class, where
-		// both openebs-operator and openebs-storage-class components must be fully functional, before
-		// prometheus-operator is deployed, otherwise it won't pick the default storage class.
-		install.Wait = wait
-
-		if _, err := install.Run(chart, map[string]interface{}{}); err != nil {
-			return fmt.Errorf("installing component '%s' as chart failed: %w", name, err)
-		}
-
-		return nil
+		return install(helmAction, ns)
 	}
 
-	upgrade := action.NewUpgrade(actionConfig)
-	upgrade.Wait = wait
+	return upgrade(helmAction)
+}
+
+type helmAction struct {
+	releaseName  string
+	chart        *chart.Chart
+	actionConfig *action.Configuration
+	wait         bool
+}
+
+func install(helmAction *helmAction, namespace string) error {
+	install := action.NewInstall(helmAction.actionConfig)
+	install.ReleaseName = helmAction.releaseName
+	install.Namespace = namespace
+
+	// Currently, we install components one-by-one, in the order how they are
+	// defined in the configuration and we do not support any dependencies between
+	// the components.
+	//
+	// If it is critical for component to have it's dependencies ready before it is
+	// installed, all dependencies should set Wait field to 'true' in components.HelmMetadata
+	// struct.
+	//
+	// The example of such dependency is between prometheus-operator and openebs-storage-class, where
+	// both openebs-operator and openebs-storage-class components must be fully functional, before
+	// prometheus-operator is deployed, otherwise it won't pick the default storage class.
+	install.Wait = helmAction.wait
+
+	if _, err := install.Run(helmAction.chart, map[string]interface{}{}); err != nil {
+		return fmt.Errorf("installing release failed: %w", err)
+	}
+
+	return nil
+}
+
+func upgrade(helmAction *helmAction) error {
+	upgrade := action.NewUpgrade(helmAction.actionConfig)
+	upgrade.Wait = helmAction.wait
 	upgrade.RecreateResources = true
 
-	if _, err := upgrade.Run(name, chart, map[string]interface{}{}); err != nil {
-		return fmt.Errorf("updating chart failed: %w", err)
+	if _, err := upgrade.Run(helmAction.releaseName, helmAction.chart, map[string]interface{}{}); err != nil {
+		return fmt.Errorf("upgrading release failed: %w", err)
 	}
 
 	return nil