confirm before overriding installation by another manager

Signed-off-by: Somtochi Onyekwere <somtochionyekwere@gmail.com>

cmd/flux/bootstrap.go

@@ -17,11 +17,15 @@ limitations under the License.
 package main
 
 import (
+	"context"
 	"crypto/elliptic"
 	"fmt"
 	"strings"
 
+	"github.com/manifoldco/promptui"
 	"github.com/spf13/cobra"
+	"k8s.io/apimachinery/pkg/api/errors"
+	"sigs.k8s.io/controller-runtime/pkg/client"
 
 	"github.com/fluxcd/flux2/v2/internal/flags"
 	"github.com/fluxcd/flux2/v2/internal/utils"
@@ -72,6 +76,8 @@ type bootstrapFlags struct {
 	gpgPassphrase  string
 	gpgKeyID       string
 
+	force bool
+
 	commitMessageAppendix string
 }
 
@@ -129,6 +135,7 @@ func init() {
 
 	bootstrapCmd.PersistentFlags().StringVar(&bootstrapArgs.commitMessageAppendix, "commit-message-appendix", "", "string to add to the commit messages, e.g. '[ci skip]'")
 
+	bootstrapCmd.PersistentFlags().BoolVar(&bootstrapArgs.force, "force", false, "override existing Flux installation if it's managed by a diffrent tool such as Helm")
 	bootstrapCmd.PersistentFlags().MarkHidden("manifests")
 
 	rootCmd.AddCommand(bootstrapCmd)
@@ -188,3 +195,27 @@ func mapTeamSlice(s []string, defaultPermission string) map[string]string {
 
 	return m
 }
+
+// confirmBootstrap gets a confirmation for running bootstrap over an existing Flux installation.
+// It returns a nil error if Flux is not installed or the user confirms overriding an existing installation
+func confirmBootstrap(ctx context.Context, kubeClient client.Client) error {
+	installed := true
+	info, err := getFluxClusterInfo(ctx, kubeClient)
+	if err != nil {
+		if !errors.IsNotFound(err) {
+			return fmt.Errorf("cluster info unavailable: %w", err)
+		}
+		installed = false
+	}
+
+	if installed {
+		err = confirmFluxInstallOverride(info)
+		if err != nil {
+			if err == promptui.ErrAbort {
+				return fmt.Errorf("bootstrap cancelled")
+			}
+			return err
+		}
+	}
+	return nil
+}

cmd/flux/bootstrap_bitbucket_server.go

@@ -124,6 +124,13 @@ func bootstrapBServerCmdRun(cmd *cobra.Command, args []string) error {
 		return err
 	}
 
+	if !bootstrapArgs.force {
+		err = confirmBootstrap(ctx, kubeClient)
+		if err != nil {
+			return err
+		}
+	}
+
 	// Manifest base
 	if ver, err := getVersion(bootstrapArgs.version); err != nil {
 		return err

cmd/flux/bootstrap_git.go

@@ -146,6 +146,13 @@ func bootstrapGitCmdRun(cmd *cobra.Command, args []string) error {
 		return err
 	}
 
+	if !bootstrapArgs.force {
+		err = confirmBootstrap(ctx, kubeClient)
+		if err != nil {
+			return err
+		}
+	}
+
 	// Manifest base
 	if ver, err := getVersion(bootstrapArgs.version); err != nil {
 		return err

cmd/flux/bootstrap_github.go

@@ -128,6 +128,13 @@ func bootstrapGitHubCmdRun(cmd *cobra.Command, args []string) error {
 		return err
 	}
 
+	if !bootstrapArgs.force {
+		err = confirmBootstrap(ctx, kubeClient)
+		if err != nil {
+			return err
+		}
+	}
+
 	// Manifest base
 	if ver, err := getVersion(bootstrapArgs.version); err != nil {
 		return err

cmd/flux/bootstrap_gitlab.go

@@ -145,6 +145,13 @@ func bootstrapGitLabCmdRun(cmd *cobra.Command, args []string) error {
 		return err
 	}
 
+	if !bootstrapArgs.force {
+		err = confirmBootstrap(ctx, kubeClient)
+		if err != nil {
+			return err
+		}
+	}
+
 	// Manifest base
 	if ver, err := getVersion(bootstrapArgs.version); err != nil {
 		return err

cmd/flux/cluster_info.go

@@ -20,8 +20,8 @@ import (
 	"context"
 	"fmt"
 
+	"github.com/manifoldco/promptui"
 	apiextensionsv1 "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1"
-	"k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 
@@ -47,12 +47,13 @@ type fluxClusterInfo struct {
 }
 
 // getFluxClusterInfo returns information on the Flux installation running on the cluster.
-// If the information cannot be retrieved, the boolean return value will be false.
 // If an error occurred, the returned error will be non-nil.
 //
 // This function retrieves the GitRepository CRD from the cluster and checks it
 // for a set of labels used to determine the Flux version and how Flux was installed.
-func getFluxClusterInfo(ctx context.Context, c client.Client) (fluxClusterInfo, bool, error) {
+// It returns the NotFound error from the underlying library if it was unable to find
+// the GitRepository CRD and this can be used to check if Flux is installed.
+func getFluxClusterInfo(ctx context.Context, c client.Client) (fluxClusterInfo, error) {
 	var info fluxClusterInfo
 	crdMetadata := &metav1.PartialObjectMetadata{
 		TypeMeta: metav1.TypeMeta{
@@ -64,10 +65,7 @@ func getFluxClusterInfo(ctx context.Context, c client.Client) (fluxClusterInfo,
 		},
 	}
 	if err := c.Get(ctx, client.ObjectKeyFromObject(crdMetadata), crdMetadata); err != nil {
-		if errors.IsNotFound(err) {
+		return info, err
-			return info, false, nil
-		}
-		return info, false, err
 	}
 
 	info.version = crdMetadata.Labels["app.kubernetes.io/version"]
@@ -80,8 +78,29 @@ func getFluxClusterInfo(ctx context.Context, c client.Client) (fluxClusterInfo,
 		info.bootstrapped = true
 	}
 
+	// the `app.kubernetes.io` label is not set by flux but might be set by other
+	// tools used to install Flux e.g Helm.
 	if manager, ok := crdMetadata.Labels["app.kubernetes.io/managed-by"]; ok {
 		info.managedBy = manager
 	}
-	return info, true, nil
+	return info, nil
+}
+
+// confirmFluxInstallOverride displays a prompt to the user so that they can confirm before overriding
+// a Flux installation. It returns nil if the installation should continue,
+// promptui.ErrAbort if the user doesn't confirm, or an error encountered.
+func confirmFluxInstallOverride(info fluxClusterInfo) error {
+	// no need to display prompt if installation is managed by Flux
+	if info.managedBy == "" || info.managedBy == "flux" {
+		return nil
+	}
+
+	display := fmt.Sprintf("Flux %s has been installed on this cluster with %s!", info.version, info.managedBy)
+	fmt.Fprintln(rootCmd.ErrOrStderr(), display)
+	prompt := promptui.Prompt{
+		Label:     fmt.Sprintf("Are you sure you want to override the %s installation? Y/N", info.managedBy),
+		IsConfirm: true,
+	}
+	_, err := prompt.Run()
+	return err
 }

cmd/flux/cluster_info_test.go

@@ -24,6 +24,7 @@ import (
 
 	. "github.com/onsi/gomega"
 	apiextensionsv1 "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1"
+	"k8s.io/apimachinery/pkg/api/errors"
 	"k8s.io/apimachinery/pkg/runtime"
 	"sigs.k8s.io/controller-runtime/pkg/client/fake"
 
@@ -44,12 +45,11 @@ func Test_getFluxClusterInfo(t *testing.T) {
 		name     string
 		labels   map[string]string
 		wantErr  bool
-		wantBool bool
 		wantInfo fluxClusterInfo
 	}{
 		{
-			name:     "no git repository CRD present",
+			name:    "no git repository CRD present",
-			wantBool: false,
+			wantErr: true,
 		},
 		{
 			name: "CRD with kustomize-controller labels",
@@ -58,7 +58,6 @@ func Test_getFluxClusterInfo(t *testing.T) {
 				fmt.Sprintf("%s/namespace", kustomizev1.GroupVersion.Group): "flux-system",
 				"app.kubernetes.io/version":                                 "v2.1.0",
 			},
-			wantBool: true,
 			wantInfo: fluxClusterInfo{
 				version:      "v2.1.0",
 				bootstrapped: true,
@@ -72,7 +71,6 @@ func Test_getFluxClusterInfo(t *testing.T) {
 				"app.kubernetes.io/version":                                 "v2.1.0",
 				"app.kubernetes.io/managed-by":                              "flux",
 			},
-			wantBool: true,
 			wantInfo: fluxClusterInfo{
 				version:      "v2.1.0",
 				bootstrapped: true,
@@ -85,7 +83,6 @@ func Test_getFluxClusterInfo(t *testing.T) {
 				"app.kubernetes.io/version":    "v2.1.0",
 				"app.kubernetes.io/managed-by": "helm",
 			},
-			wantBool: true,
 			wantInfo: fluxClusterInfo{
 				version:   "v2.1.0",
 				managedBy: "helm",
@@ -94,14 +91,13 @@ func Test_getFluxClusterInfo(t *testing.T) {
 		{
 			name:     "CRD with no labels",
 			labels:   map[string]string{},
-			wantBool: true,
+			wantInfo: fluxClusterInfo{},
 		},
 		{
 			name: "CRD with only version label",
 			labels: map[string]string{
 				"app.kubernetes.io/version": "v2.1.0",
 			},
-			wantBool: true,
 			wantInfo: fluxClusterInfo{
 				version: "v2.1.0",
 			},
@@ -120,12 +116,14 @@ func Test_getFluxClusterInfo(t *testing.T) {
 			}
 
 			client := builder.Build()
-			info, present, err := getFluxClusterInfo(context.Background(), client)
+			info, err := getFluxClusterInfo(context.Background(), client)
 			if tt.wantErr {
 				g.Expect(err).To(HaveOccurred())
+				g.Expect(errors.IsNotFound(err)).To(BeTrue())
+			} else {
+				g.Expect(err).To(Not(HaveOccurred()))
 			}
 
-			g.Expect(present).To(Equal(tt.wantBool))
 			g.Expect(info).To(BeEquivalentTo(tt.wantInfo))
 		})
 	}

cmd/flux/install.go

@@ -23,7 +23,9 @@ import (
 	"path/filepath"
 	"time"
 
+	"github.com/manifoldco/promptui"
 	"github.com/spf13/cobra"
+	"k8s.io/apimachinery/pkg/api/errors"
 
 	"github.com/fluxcd/flux2/v2/internal/flags"
 	"github.com/fluxcd/flux2/v2/internal/utils"
@@ -72,6 +74,7 @@ type installFlags struct {
 	tokenAuth          bool
 	clusterDomain      string
 	tolerationKeys     []string
+	force              bool
 }
 
 var installArgs = NewInstallFlags()
@@ -98,6 +101,7 @@ func init() {
 	installCmd.Flags().StringVar(&installArgs.clusterDomain, "cluster-domain", rootArgs.defaults.ClusterDomain, "internal cluster domain")
 	installCmd.Flags().StringSliceVar(&installArgs.tolerationKeys, "toleration-keys", nil,
 		"list of toleration keys used to schedule the components pods onto nodes with matching taints")
+	installCmd.Flags().BoolVar(&installArgs.force, "force", false, "override existing Flux installation if it's managed by a diffrent tool such as Helm")
 	installCmd.Flags().MarkHidden("manifests")
 
 	rootCmd.AddCommand(installCmd)
@@ -188,13 +192,28 @@ func installCmdRun(cmd *cobra.Command, args []string) error {
 		return err
 	}
 
-	info, installed, err := getFluxClusterInfo(ctx, kubeClient)
+	installed := true
+	info, err := getFluxClusterInfo(ctx, kubeClient)
 	if err != nil {
-		return fmt.Errorf("cluster info unavailable: %w", err)
+		if !errors.IsNotFound(err) {
+			return fmt.Errorf("cluster info unavailable: %w", err)
+		}
+		installed = false
+	}
+
+	if info.bootstrapped {
+		return fmt.Errorf("this cluster has already been bootstrapped with Flux %s! Please use 'flux bootstrap' to upgrade",
+			info.version)
 	}
 
-	if installed && info.bootstrapped {
+	if installed && !installArgs.force {
-		return fmt.Errorf("this cluster has already been bootstrapped with Flux %s! Please use 'flux bootstrap' to upgrade", info.version)
+		err := confirmFluxInstallOverride(info)
+		if err != nil {
+			if err == promptui.ErrAbort {
+				return fmt.Errorf("installation cancelled")
+			}
+			return err
+		}
 	}
 
 	applyOutput, err := utils.Apply(ctx, kubeconfigArgs, kubeclientOptions, tmpDir, filepath.Join(tmpDir, manifest.Path))