Move utility functions dealing with IAM to libs/iamutil (#1820)

## Changes

The two functions `GetShortUserName` and `IsServicePrincipal` are
unrelated to auth or the purpose of the auth package. This change moves
them into their own package and updates `IsServicePrincipal` to take an
`*iam.User` argument instead of a string username.

## Tests

Tests pass.

bundle/config/mutator/populate_current_user.go

@@ -5,8 +5,8 @@ import (
 
 	"github.com/databricks/cli/bundle"
 	"github.com/databricks/cli/bundle/config"
-	"github.com/databricks/cli/libs/auth"
 	"github.com/databricks/cli/libs/diag"
+	"github.com/databricks/cli/libs/iamutil"
 	"github.com/databricks/cli/libs/tags"
 )
 
@@ -33,7 +33,7 @@ func (m *populateCurrentUser) Apply(ctx context.Context, b *bundle.Bundle) diag.
 	}
 
 	b.Config.Workspace.CurrentUser = &config.User{
-		ShortName: auth.GetShortUserName(me),
+		ShortName: iamutil.GetShortUserName(me),
 		User:      me,
 	}
 

bundle/config/mutator/process_target_mode.go

@@ -6,9 +6,9 @@ import (
 
 	"github.com/databricks/cli/bundle"
 	"github.com/databricks/cli/bundle/config"
-	"github.com/databricks/cli/libs/auth"
 	"github.com/databricks/cli/libs/diag"
 	"github.com/databricks/cli/libs/dyn"
+	"github.com/databricks/cli/libs/iamutil"
 	"github.com/databricks/cli/libs/log"
 )
 
@@ -174,7 +174,7 @@ func (m *processTargetMode) Apply(ctx context.Context, b *bundle.Bundle) diag.Di
 		transformDevelopmentMode(ctx, b)
 		return diags
 	case config.Production:
-		isPrincipal := auth.IsServicePrincipal(b.Config.Workspace.CurrentUser.UserName)
+		isPrincipal := iamutil.IsServicePrincipal(b.Config.Workspace.CurrentUser.User)
 		return validateProductionMode(ctx, b, isPrincipal)
 	case "":
 		// No action

bundle/permissions/permission_report.go

@@ -5,8 +5,8 @@ import (
 	"fmt"
 
 	"github.com/databricks/cli/bundle"
-	"github.com/databricks/cli/libs/auth"
 	"github.com/databricks/cli/libs/diag"
+	"github.com/databricks/cli/libs/iamutil"
 	"github.com/databricks/cli/libs/log"
 )
 
@@ -17,9 +17,10 @@ import (
 func ReportPossiblePermissionDenied(ctx context.Context, b *bundle.Bundle, path string) diag.Diagnostics {
 	log.Errorf(ctx, "Failed to update, encountered possible permission error: %v", path)
 
-	user := b.Config.Workspace.CurrentUser.UserName
-	if auth.IsServicePrincipal(user) {
-		user = b.Config.Workspace.CurrentUser.DisplayName
+	me := b.Config.Workspace.CurrentUser.User
+	userName := me.UserName
+	if iamutil.IsServicePrincipal(me) {
+		userName = me.DisplayName
 	}
 	canManageBundle, assistance := analyzeBundlePermissions(b)
 
@@ -30,7 +31,7 @@ func ReportPossiblePermissionDenied(ctx context.Context, b *bundle.Bundle, path
 				"%s\n"+
 				"They may need to redeploy the bundle to apply the new permissions.\n"+
 				"Please refer to https://docs.databricks.com/dev-tools/bundles/permissions.html for more on managing permissions.",
-				path, user, assistance),
+				path, userName, assistance),
 			Severity: diag.Error,
 			ID:       diag.PathPermissionDenied,
 		}}
@@ -44,7 +45,7 @@ func ReportPossiblePermissionDenied(ctx context.Context, b *bundle.Bundle, path
 			"%s\n"+
 			"They can redeploy the project to apply the latest set of permissions.\n"+
 			"Please refer to https://docs.databricks.com/dev-tools/bundles/permissions.html for more on managing permissions.",
-			path, user, assistance),
+			path, userName, assistance),
 		Severity: diag.Error,
 		ID:       diag.CannotChangePathPermissions,
 	}}

internal/init_test.go

@@ -12,7 +12,7 @@ import (
 
 	"github.com/databricks/cli/bundle/config"
 	"github.com/databricks/cli/internal/testutil"
-	"github.com/databricks/cli/libs/auth"
+	"github.com/databricks/cli/libs/iamutil"
 	"github.com/databricks/databricks-sdk-go"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -126,7 +126,7 @@ func TestAccBundleInitHelpers(t *testing.T) {
 	}{
 		{
 			funcName: "{{short_name}}",
-			expected: auth.GetShortUserName(me),
+			expected: iamutil.GetShortUserName(me),
 		},
 		{
 			funcName: "{{user_name}}",
@@ -138,7 +138,7 @@ func TestAccBundleInitHelpers(t *testing.T) {
 		},
 		{
 			funcName: "{{is_service_principal}}",
-			expected: strconv.FormatBool(auth.IsServicePrincipal(me.UserName)),
+			expected: strconv.FormatBool(iamutil.IsServicePrincipal(me)),
 		},
 		{
 			funcName: "{{smallest_node_type}}",

libs/iamutil/service_principal.go

@@ -1,15 +1,16 @@
-package auth
+package iamutil
 
 import (
+	"github.com/databricks/databricks-sdk-go/service/iam"
 	"github.com/google/uuid"
 )
 
-// Determines whether a given user name is a service principal.
+// Determines whether a given user is a service principal.
 // This function uses a heuristic: if the user name is a UUID, then we assume
 // it's a service principal. Unfortunately, the service principal listing API is too
 // slow for our purposes. And the "users" and "service principals get" APIs
 // only allow access by workspace admins.
-func IsServicePrincipal(userName string) bool {
-	_, err := uuid.Parse(userName)
+func IsServicePrincipal(user *iam.User) bool {
+	_, err := uuid.Parse(user.UserName)
 	return err == nil
 }

libs/iamutil/service_principal_test.go

@@ -1,19 +1,24 @@
-package auth
+package iamutil
 
 import (
 	"testing"
 
+	"github.com/databricks/databricks-sdk-go/service/iam"
 	"github.com/stretchr/testify/assert"
 )
 
 func TestIsServicePrincipal_ValidUUID(t *testing.T) {
-	userId := "8b948b2e-d2b5-4b9e-8274-11b596f3b652"
-	isSP := IsServicePrincipal(userId)
+	user := &iam.User{
+		UserName: "8b948b2e-d2b5-4b9e-8274-11b596f3b652",
+	}
+	isSP := IsServicePrincipal(user)
 	assert.True(t, isSP, "Expected user ID to be recognized as a service principal")
 }
 
 func TestIsServicePrincipal_InvalidUUID(t *testing.T) {
-	userId := "invalid"
-	isSP := IsServicePrincipal(userId)
+	user := &iam.User{
+		UserName: "invalid",
+	}
+	isSP := IsServicePrincipal(user)
 	assert.False(t, isSP, "Expected user ID to not be recognized as a service principal")
 }

libs/iamutil/user.go

@@ -1,4 +1,4 @@
-package auth
+package iamutil
 
 import (
 	"strings"
@@ -12,7 +12,7 @@ import (
 // including dots, which are not supported in e.g. experiment names.
 func GetShortUserName(user *iam.User) string {
 	name := user.UserName
-	if IsServicePrincipal(user.UserName) && user.DisplayName != "" {
+	if IsServicePrincipal(user) && user.DisplayName != "" {
 		name = user.DisplayName
 	}
 	local, _, _ := strings.Cut(name, "@")

libs/iamutil/user_test.go

@@ -1,4 +1,4 @@
-package auth
+package iamutil
 
 import (
 	"testing"

libs/template/helpers.go

@@ -11,7 +11,7 @@ import (
 	"text/template"
 
 	"github.com/databricks/cli/cmd/root"
-	"github.com/databricks/cli/libs/auth"
+	"github.com/databricks/cli/libs/iamutil"
 	"github.com/databricks/databricks-sdk-go/apierr"
 	"github.com/databricks/databricks-sdk-go/service/iam"
 
@@ -119,7 +119,7 @@ func loadHelpers(ctx context.Context) template.FuncMap {
 					return "", err
 				}
 			}
-			return auth.GetShortUserName(cachedUser), nil
+			return iamutil.GetShortUserName(cachedUser), nil
 		},
 		// Get the default workspace catalog. If there is no default, or if
 		// Unity Catalog is not enabled, return an empty string.
@@ -151,7 +151,7 @@ func loadHelpers(ctx context.Context) template.FuncMap {
 					return false, err
 				}
 			}
-			result := auth.IsServicePrincipal(cachedUser.UserName)
+			result := iamutil.IsServicePrincipal(cachedUser)
 			cachedIsServicePrincipal = &result
 			return result, nil
 		},