add flag --prompt-ssh-username to override username

Add a new flag --prompt-ssh-username which prompts users for a SSH
username to be used which will override the value of the flag
--username. This enables a flow where some git providers, for eg, AWS
CodeCommit, assign SSH usernames to be used for a public key after its
attached to the IAM user.

Signed-off-by: Sanskar Jaiswal <jaiswalsanskar078@gmail.com>

cmd/flux/bootstrap.go

@@ -51,14 +51,16 @@ type bootstrapFlags struct {
 	registry        string
 	imagePullSecret string
 
-	secretName     string
-	tokenAuth      bool
-	keyAlgorithm   flags.PublicKeyAlgorithm
-	keyRSABits     flags.RSAKeyBits
-	keyECDSACurve  flags.ECDSACurve
-	sshHostname    string
-	caFile         string
-	privateKeyFile string
+	secretName        string
+	tokenAuth         bool
+	promptSSHUsername bool
+	keyAlgorithm      flags.PublicKeyAlgorithm
+	keyRSABits        flags.RSAKeyBits
+	keyECDSACurve     flags.ECDSACurve
+	sshHostname       string
+	caFile            string
+	privateKeyFile    string
+	sshUsername       string
 
 	watchAllNamespaces bool
 	networkPolicy      bool
@@ -107,6 +109,8 @@ func init() {
 		"deny ingress access to the toolkit controllers from other namespaces using network policies")
 	bootstrapCmd.PersistentFlags().BoolVar(&bootstrapArgs.tokenAuth, "token-auth", false,
 		"when enabled, the personal access token will be used instead of SSH deploy key")
+	bootstrapCmd.PersistentFlags().BoolVar(&bootstrapArgs.promptSSHUsername, "prompt-ssh-username", false,
+		"when enabled, you'll be prompted for the SSH username to override the HTTPS username")
 	bootstrapCmd.PersistentFlags().Var(&bootstrapArgs.logLevel, "log-level", bootstrapArgs.logLevel.Description())
 	bootstrapCmd.PersistentFlags().StringVar(&bootstrapArgs.clusterDomain, "cluster-domain", rootArgs.defaults.ClusterDomain, "internal cluster domain")
 	bootstrapCmd.PersistentFlags().StringSliceVar(&bootstrapArgs.tolerationKeys, "toleration-keys", nil,

cmd/flux/bootstrap_git.go

@@ -258,6 +258,7 @@ func bootstrapGitCmdRun(cmd *cobra.Command, args []string) error {
 		bootstrap.WithCommitMessageAppendix(bootstrapArgs.commitMessageAppendix),
 		bootstrap.WithKubeconfig(kubeconfigArgs, kubeclientOptions),
 		bootstrap.WithPostGenerateSecretFunc(promptPublicKey),
+		bootstrap.WithPromptSSHUsernameFunc(promptSSHUsername),
 		bootstrap.WithLogger(logger),
 		bootstrap.WithGitCommitSigning(entityList, bootstrapArgs.gpgPassphrase, bootstrapArgs.gpgKeyID),
 	}
@@ -338,3 +339,17 @@ func promptPublicKey(ctx context.Context, secret corev1.Secret, _ sourcesecret.O
 	}
 	return nil
 }
+
+func promptSSHUsername(ctx context.Context) (string, error) {
+	if !gitArgs.silent && bootstrapArgs.promptSSHUsername {
+		prompt := promptui.Prompt{
+			Label: "Please enter the SSH username",
+		}
+		sshUsername, err := prompt.Run()
+		if err != nil {
+			return "", fmt.Errorf("aborting")
+		}
+		return sshUsername, nil
+	}
+	return "", nil
+}

pkg/bootstrap/bootstrap.go

@@ -76,6 +76,8 @@ type RepositoryReconciler interface {
 
 type PostGenerateSecretFunc func(ctx context.Context, secret corev1.Secret, options sourcesecret.Options) error
 
+type PromptSSHUSernameFunc func(ctx context.Context) (string, error)
+
 func Run(ctx context.Context, reconciler Reconciler, manifestsBase string,
 	installOpts install.Options, secretOpts sourcesecret.Options, syncOpts sync.Options,
 	pollInterval, timeout time.Duration) error {

pkg/bootstrap/bootstrap_plain_git.go

@@ -20,6 +20,7 @@ import (
 	"context"
 	"fmt"
 	"io"
+	"net/url"
 	"os"
 	"path/filepath"
 	"strings"
@@ -65,6 +66,7 @@ type PlainGitBootstrapper struct {
 	restClientOptions *runclient.Options
 
 	postGenerateSecret []PostGenerateSecretFunc
+	promptSSHUsername  PromptSSHUSernameFunc
 
 	gitClient git.RepositoryClient
 	kube      client.Client
@@ -95,6 +97,16 @@ func (o postGenerateSecret) applyGit(b *PlainGitBootstrapper) {
 	b.postGenerateSecret = append(b.postGenerateSecret, PostGenerateSecretFunc(o))
 }
 
+func WithPromptSSHUsernameFunc(callback PromptSSHUSernameFunc) GitOption {
+	return promptSSHUsername(callback)
+}
+
+type promptSSHUsername PromptSSHUSernameFunc
+
+func (o promptSSHUsername) applyGit(b *PlainGitBootstrapper) {
+	b.promptSSHUsername = PromptSSHUSernameFunc(o)
+}
+
 func NewPlainGitProvider(git git.RepositoryClient, kube client.Client, opts ...GitOption) (*PlainGitBootstrapper, error) {
 	b := &PlainGitBootstrapper{
 		gitClient: git,
@@ -276,6 +288,19 @@ func (b *PlainGitBootstrapper) ReconcileSyncConfig(ctx context.Context, options
 		return err
 	}
 
+	sshUsername, err := b.promptSSHUsername(ctx)
+	if err != nil {
+		return fmt.Errorf("prompting for ssh username failed: %w", err)
+	}
+	if sshUsername != "" {
+		repoURL, err := url.Parse(options.URL)
+		if err != nil {
+			return fmt.Errorf("unable to parse url: %w", err)
+		}
+		repoURL.User = url.User(sshUsername)
+		options.URL = repoURL.String()
+	}
+
 	// Generate sync manifests and write to Git repository
 	b.logger.Actionf("generating sync manifests")
 	manifests, err := sync.Generate(options)