refactor: use os.File for apply

Author: thde

apply/apply.go

@@ -1,6 +1,8 @@
 package apply
 
+import "os"
+
 type Cmd struct {
-	Filename string   `short:"f" predictor:"file"`
+	Filename *os.File `short:"f" predictor:"file"`
 	FromFile fromFile `cmd:"" default:"1" name:"-f <file>" help:"Apply any resource from a yaml or json file."`
 }

apply/file.go

@@ -40,23 +40,19 @@ func Delete() Option {
 	}
 }
 
-func File(ctx context.Context, client *api.Client, filename string, opts ...Option) error {
-	if len(filename) == 0 {
+func File(ctx context.Context, client *api.Client, file *os.File, opts ...Option) error {
+	if file == nil {
 		return fmt.Errorf("missing flag -f, --filename=STRING")
 	}
+	defer file.Close()
 
 	cfg := &config{}
 	for _, opt := range opts {
 		opt(cfg)
 	}
 
-	f, err := os.Open(filename)
-	if err != nil {
-		return err
-	}
-
 	obj := &unstructured.Unstructured{}
-	if err := yaml.NewYAMLOrJSONDecoder(f, 4096).Decode(obj); err != nil {
+	if err := yaml.NewYAMLOrJSONDecoder(file, 4096).Decode(obj); err != nil {
 		return err
 	}
 

apply/file_test.go

@@ -118,39 +118,39 @@ func TestFile(t *testing.T) {
 			if _, err := fmt.Fprintf(f, tc.file, name, "value", runtimev1.DeletionOrphan); err != nil {
 				t.Fatal(err)
 			}
+			// The file is written, but the pointer is at the end.
+			// Close it to flush content.
+			require.NoError(t, f.Close())
 
 			opts := []Option{}
 
+			// For delete and update tests, we first create the resource.
+			if tc.delete || tc.update {
+				fileToCreate, err := os.Open(f.Name())
+				require.NoError(t, err)
+				err = File(ctx, apiClient, fileToCreate) // This will close fileToCreate
+				require.NoError(t, err)
+			}
+
 			if tc.delete {
-				// we need to ensure that the resource exists before we can delete it
-				if err := File(ctx, apiClient, f.Name()); err != nil {
-					t.Fatal(err)
-				}
 				opts = append(opts, Delete())
 			}
 
 			if tc.update {
-				// we need to ensure that the resource exists before we can update
-				if err := File(ctx, apiClient, f.Name()); err != nil {
-					t.Fatal(err)
-				}
-
-				if err := f.Truncate(0); err != nil {
-					t.Fatal(err)
-				}
-
-				if _, err := f.Seek(0, 0); err != nil {
-					t.Fatal(err)
-				}
-
-				if _, err := fmt.Fprintf(f, tc.file, name, tc.updatedAnnotation, tc.updatedSpecValue); err != nil {
-					t.Fatal(err)
-				}
+				// Re-create the file to truncate it and write the updated content.
+				updatedFile, err := os.Create(f.Name())
+				require.NoError(t, err)
+				_, err = fmt.Fprintf(updatedFile, tc.file, name, tc.updatedAnnotation, tc.updatedSpecValue)
+				require.NoError(t, err)
+				require.NoError(t, updatedFile.Close())
 
 				opts = append(opts, UpdateOnExists())
 			}
 
-			if err := File(ctx, apiClient, f.Name(), opts...); err != nil {
+			fileToApply, err := os.Open(f.Name())
+			require.NoError(t, err)
+
+			if err := File(ctx, apiClient, fileToApply, opts...); err != nil {
 				if tc.expectedErr {
 					return
 				}

create/create.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"math/rand"
+	"os"
 	"time"
 
 	runtimev1 "github.com/crossplane/crossplane-runtime/apis/common/v1"
@@ -20,7 +21,7 @@ import (
 )
 
 type Cmd struct {
-	Filename            string               `short:"f" help:"Create any resource from a yaml or json file." predictor:"file"`
+	Filename            *os.File             `short:"f" help:"Create any resource from a yaml or json file." predictor:"file"`
 	FromFile            fromFile             `cmd:"" default:"1" name:"-f <file>" help:"Create any resource from a yaml or json file."`
 	VCluster            vclusterCmd          `cmd:"" group:"infrastructure.nine.ch" name:"vcluster" help:"Create a new vcluster."`
 	APIServiceAccount   apiServiceAccountCmd `cmd:"" group:"iam.nine.ch" name:"apiserviceaccount" aliases:"asa" help:"Create a new API Service Account."`

create/mysql.go

@@ -25,7 +25,7 @@ type mySQLCmd struct {
 	MachineType           string                                 `placeholder:"${mysql_machine_default}" help:"Defines the sizing for a particular MySQL instance. Available types: ${mysql_machine_types}"`
 	AllowedCidrs          []meta.IPv4CIDR                        `placeholder:"203.0.113.1/32" help:"Specifies the IP addresses allowed to connect to the instance." `
 	SSHKeys               []storage.SSHKey                       `help:"Contains a list of SSH public keys, allowed to connect to the db server, in order to up-/download and directly restore database backups."`
-	SSHKeysFile           *os.File                               `help:"Path to a file containing a list of SSH public keys (see above), separated by newlines. Lines prefixed with # are ignored."`
+	SSHKeysFile           *os.File                               `predictor:"file" help:"Path to a file containing a list of SSH public keys (see above), separated by newlines. Lines prefixed with # are ignored."`
 	SQLMode               *[]storage.MySQLMode                   `placeholder:"\"MODE1, MODE2, ...\"" help:"Configures the sql_mode setting. Modes affect the SQL syntax MySQL supports and the data validation checks it performs. Defaults to: ${mysql_mode}"`
 	CharacterSetName      string                                 `placeholder:"${mysql_charset}" help:"Configures the character_set_server variable."`
 	CharacterSetCollation string                                 `placeholder:"${mysql_collation}" help:"Configures the collation_server variable."`

create/postgres.go

@@ -24,7 +24,7 @@ type postgresCmd struct {
 	MachineType      string                  `placeholder:"${postgres_machine_default}" help:"Defines the sizing for a particular PostgreSQL instance. Available types: ${postgres_machine_types}"`
 	AllowedCidrs     []meta.IPv4CIDR         `placeholder:"203.0.113.1/32" help:"Specifies the IP addresses allowed to connect to the instance." `
 	SSHKeys          []storage.SSHKey        `help:"Contains a list of SSH public keys, allowed to connect to the db server, in order to up-/download and directly restore database backups."`
-	SSHKeysFile      *os.File                `help:"Path to a file containing a list of SSH public keys (see above), separated by newlines. Lines prefixed with # are ignored."`
+	SSHKeysFile      *os.File                `predictor:"file" help:"Path to a file containing a list of SSH public keys (see above), separated by newlines. Lines prefixed with # are ignored."`
 	PostgresVersion  storage.PostgresVersion `placeholder:"${postgres_version_default}" help:"Release version with which the PostgreSQL instance is created. Available versions: ${postgres_versions}"`
 	KeepDailyBackups *int                    `placeholder:"${postgres_backup_retention_days}" help:"Number of daily database backups to keep. Note that setting this to 0, backup will be disabled and existing dumps deleted immediately."`
 }

delete/delete.go

@@ -3,6 +3,7 @@ package delete
 import (
 	"context"
 	"fmt"
+	"os"
 	"time"
 
 	"github.com/crossplane/crossplane-runtime/pkg/resource"
@@ -12,7 +13,7 @@ import (
 )
 
 type Cmd struct {
-	Filename            string               `short:"f" predictor:"file"`
+	Filename            *os.File             `short:"f" predictor:"file"`
 	FromFile            fromFile             `cmd:"" default:"1" name:"-f <file>" help:"Delete any resource from a yaml or json file."`
 	VCluster            vclusterCmd          `cmd:"" group:"infrastructure.nine.ch" name:"vcluster" help:"Delete a vcluster."`
 	APIServiceAccount   apiServiceAccountCmd `cmd:"" group:"iam.nine.ch" name:"apiserviceaccount" aliases:"asa" help:"Delete an API Service Account."`

go.sum

@@ -579,8 +579,6 @@ github.com/mwitkow/go-conntrack v0.0.0-20190716064945-2f068394615f/go.mod h1:qRW
 github.com/mxk/go-flowrate v0.0.0-20140419014527-cca7078d478f h1:y5//uYreIhSUg3J1GEMiLbxo1LJaP8RfCpH6pymGZus=
 github.com/mxk/go-flowrate v0.0.0-20140419014527-cca7078d478f/go.mod h1:ZdcZmHo+o7JKHSa8/e818NopupXU1YMK5fe1lsApnBw=
 github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e/go.mod h1:zD1mROLANZcx1PVRCS0qkT7pwLkGfwJo4zjcN/Tysno=
-github.com/ninech/apis v0.0.0-20250919080229-7b9e4faad271 h1:EUdePYKqUvLDKRE8jGUYIwSCoYyDpuMyQIfKEMBLTmg=
-github.com/ninech/apis v0.0.0-20250919080229-7b9e4faad271/go.mod h1:v9N/4IvFju6G/Qp6BPanKG+V6VYsTFiytZs2hktr3Yk=
 github.com/ninech/apis v0.0.0-20250923145617-eda423f1b20a h1:HPjeOljDm2Nyc/Ypxu39AOgqQCQ6xqOd6sSHyUMnMyI=
 github.com/ninech/apis v0.0.0-20250923145617-eda423f1b20a/go.mod h1:v9N/4IvFju6G/Qp6BPanKG+V6VYsTFiytZs2hktr3Yk=
 github.com/nxadm/tail v1.4.8 h1:nPr65rt6Y5JFSKQO7qToXr7pePgD6Gwiw05lkbyAQTE=

main.go

@@ -87,27 +87,10 @@ func main() {
 		kong.BindTo(ctx, (*context.Context)(nil)),
 	)
 
-	predictors := []completion.Option{
-		completion.WithPredictor("file", complete.PredictFiles("*")),
-	}
 	apiClientRequired := !noAPIClientRequired(strings.Join(os.Args[1:], " "))
-	if apiClientRequired {
-		predictors = append(predictors,
-			completion.WithPredictor("resource_name", predictor.NewResourceName(ctx, defaultAPICluster)),
-			completion.WithPredictor("project_name", predictor.NewResourceNameWithKind(
-				ctx, defaultAPICluster, management.SchemeGroupVersion.WithKind(
-					reflect.TypeOf(management.ProjectList{}).Name(),
-				)),
-			),
-		)
-	} else {
-		// complete needs all used predictors to be defined, so we just use
-		// [complete.PredictNothing] for those that would require an API client.
-		predictors = append(predictors,
-			completion.WithPredictor("resource_name", complete.PredictNothing),
-			completion.WithPredictor("project_name", complete.PredictNothing),
-		)
-	}
+	predictors := append([]completion.Option{
+		completion.WithPredictor("file", complete.PredictFiles("*")),
+	}, clientPredictors(ctx, apiClientRequired)...)
 	completion.Register(parser, predictors...)
 
 	kongCtx, err := parser.Parse(os.Args[1:])
@@ -149,6 +132,31 @@ func main() {
 	}
 }
 
+func clientPredictors(ctx context.Context, apiClientRequired bool) []completion.Option {
+	// complete needs all used predictors to be defined, so we just use
+	// [complete.PredictNothing] for those that would require an API client.
+	nothing := []completion.Option{
+		completion.WithPredictor("resource_name", complete.PredictNothing),
+		completion.WithPredictor("project_name", complete.PredictNothing),
+	}
+
+	if !apiClientRequired {
+		return nothing
+	}
+
+	client, err := predictor.NewClient(ctx, defaultAPICluster)
+	if err != nil {
+		return nothing
+	}
+
+	return []completion.Option{
+		completion.WithPredictor("resource_name", predictor.NewResourceName(client)),
+		completion.WithPredictor("project_name", predictor.NewResourceNameWithKind(client,
+			management.SchemeGroupVersion.WithKind(reflect.TypeOf(management.ProjectList{}).Name())),
+		),
+	}
+}
+
 // noAPIClientRequired returns true if the command does not need to (or can't)
 // require an API client.
 func noAPIClientRequired(command string) bool {

predictor/predictor.go

@@ -33,21 +33,11 @@ type Resource struct {
 	knownGVK *schema.GroupVersionKind
 }
 
-func NewResourceName(ctx context.Context, defaultAPICluster string) complete.Predictor {
-	// we don't want to error in our predictor so we just return an empty predictor
-	client, err := newClient(ctx, defaultAPICluster)
-	if err != nil {
-		return complete.PredictNothing
-	}
+func NewResourceName(client *api.Client) complete.Predictor {
 	return &Resource{client: client}
 }
 
-func NewResourceNameWithKind(ctx context.Context, defaultAPICluster string, gvk schema.GroupVersionKind) complete.Predictor {
-	// we can't error in our predictor so we just return an empty predictor
-	client, err := newClient(ctx, defaultAPICluster)
-	if err != nil {
-		return complete.PredictNothing
-	}
+func NewResourceNameWithKind(client *api.Client, gvk schema.GroupVersionKind) complete.Predictor {
 	return &Resource{
 		client:   client,
 		knownGVK: ptr.To(gvk),
@@ -109,7 +99,7 @@ func listKindToResource(kind string) string {
 	return flect.Pluralize(strings.TrimSuffix(strings.ToLower(kind), listSuffix))
 }
 
-func newClient(ctx context.Context, defaultAPICluster string) (*api.Client, error) {
+func NewClient(ctx context.Context, defaultAPICluster string) (*api.Client, error) {
 	// the client for the predictor requires a static token in the client config
 	// since dynamic exec config seems to break with some shells during completion.
 	// The exact reason for that is unknown.