Centralise adapter types

Since the generic commands tend to share a few of the methods they
need -- at least AsClientObject -- it's worth having just one wrapper
struct for each API type, and adding methods to it where necessary.

For the automation types, I put these in auto.go.

While doing this I also did some tidying:

 - I changed the name of the wrappers to `<type>Adapter`, and the
   generic adapter to `universalAdapter` (it's only needed for delete,
   so far).

 - I de-exported and renamed some interface methods e.g.,
   `exportItem`. They aren't needed outside the package.

Signed-off-by: Michael Bridgen <michael@weave.works>

cmd/flux/auto.go

@@ -0,0 +1,99 @@
+/*
+Copyright 2020 The Flux authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package main
+
+import (
+	"k8s.io/apimachinery/pkg/runtime"
+
+	autov1 "github.com/fluxcd/image-automation-controller/api/v1alpha1"
+	imagev1 "github.com/fluxcd/image-reflector-controller/api/v1alpha1"
+)
+
+// These are general-purpose adapters for attaching methods to, for
+// the various commands. The *List adapters implement len(), since
+// it's used in at least a couple of commands.
+
+// imagev1.ImageRepository
+type imageRepositoryAdapter struct {
+	*imagev1.ImageRepository
+}
+
+func (a imageRepositoryAdapter) asRuntimeObject() runtime.Object {
+	return a.ImageRepository
+}
+
+// imagev1.ImageRepositoryList
+
+type imageRepositoryListAdapter struct {
+	*imagev1.ImageRepositoryList
+}
+
+func (a imageRepositoryListAdapter) asRuntimeObject() runtime.Object {
+	return a.ImageRepositoryList
+}
+
+func (a imageRepositoryListAdapter) len() int {
+	return len(a.ImageRepositoryList.Items)
+}
+
+// imagev1.ImagePolicy
+
+type imagePolicyAdapter struct {
+	*imagev1.ImagePolicy
+}
+
+func (a imagePolicyAdapter) asRuntimeObject() runtime.Object {
+	return a.ImagePolicy
+}
+
+// imagev1.ImagePolicyList
+
+type imagePolicyListAdapter struct {
+	*imagev1.ImagePolicyList
+}
+
+func (a imagePolicyListAdapter) asRuntimeObject() runtime.Object {
+	return a.ImagePolicyList
+}
+
+func (a imagePolicyListAdapter) len() int {
+	return len(a.ImagePolicyList.Items)
+}
+
+// autov1.ImageUpdateAutomation
+
+type imageUpdateAutomationAdapter struct {
+	*autov1.ImageUpdateAutomation
+}
+
+func (a imageUpdateAutomationAdapter) asRuntimeObject() runtime.Object {
+	return a.ImageUpdateAutomation
+}
+
+// autov1.ImageUpdateAutomationList
+
+type imageUpdateAutomationListAdapter struct {
+	*autov1.ImageUpdateAutomationList
+}
+
+func (a imageUpdateAutomationListAdapter) asRuntimeObject() runtime.Object {
+	return a.ImageUpdateAutomationList
+}
+
+func (a imageUpdateAutomationListAdapter) len() int {
+	return len(a.ImageUpdateAutomationList.Items)
+}

cmd/flux/delete.go

@@ -46,7 +46,7 @@ func init() {
 
 type deleteCommand struct {
 	humanKind string  // the kind being deleted, lowercase and spaced e.g., "image policy"
-	container objectContainer // for getting the value, and later deleting it
+	adapter   adapter // for getting the value, and later deleting it
 }
 
 func (del deleteCommand) run(cmd *cobra.Command, args []string) error {
@@ -68,7 +68,7 @@ func (del deleteCommand) run(cmd *cobra.Command, args []string) error {
 		Name:      name,
 	}
 
-	err = kubeClient.Get(ctx, namespacedName, del.container.AsClientObject())
+	err = kubeClient.Get(ctx, namespacedName, del.adapter.asRuntimeObject())
 	if err != nil {
 		return err
 	}
@@ -84,7 +84,7 @@ func (del deleteCommand) run(cmd *cobra.Command, args []string) error {
 	}
 
 	logger.Actionf("deleting %s %s in %s namespace", del.humanKind, name, namespace)
-	err = kubeClient.Delete(ctx, del.container.AsClientObject())
+	err = kubeClient.Delete(ctx, del.adapter.asRuntimeObject())
 	if err != nil {
 		return err
 	}

cmd/flux/delete_auto_imagepolicy.go

@@ -31,7 +31,7 @@ var deleteImagePolicyCmd = &cobra.Command{
 `,
 	RunE: deleteCommand{
 		humanKind: "image policy",
-		container: genericContainer{&imagev1.ImagePolicy{}},
+		adapter:   universalAdapter{&imagev1.ImagePolicy{}},
 	}.run,
 }
 

cmd/flux/delete_auto_imagerepository.go

@@ -31,7 +31,7 @@ var deleteImageRepositoryCmd = &cobra.Command{
 `,
 	RunE: deleteCommand{
 		humanKind: "image repository",
-		container: genericContainer{&imagev1.ImageRepository{}},
+		adapter:   universalAdapter{&imagev1.ImageRepository{}},
 	}.run,
 }
 

cmd/flux/delete_auto_imageupdateauto.go

@@ -31,7 +31,7 @@ var deleteImageUpdateCmd = &cobra.Command{
 `,
 	RunE: deleteCommand{
 		humanKind: "image update automation",
-		container: genericContainer{&autov1.ImageUpdateAutomation{}},
+		adapter:   universalAdapter{&autov1.ImageUpdateAutomation{}},
 	}.run,
 }
 

cmd/flux/export.go

@@ -48,21 +48,21 @@ func init() {
 // exportable represents a type that you can fetch from the Kubernetes
 // API, then tidy up for serialising.
 type exportable interface {
-	objectContainer
-	Export() interface{}
+	adapter
+	export() interface{}
 }
 
-// exportableAt represents a type that has a list of values, each of
+// exportableList represents a type that has a list of values, each of
 // which is exportable.
-type exportableAt interface {
-	objectContainer
-	Len() int
-	ExportAt(i int) interface{}
+type exportableList interface {
+	adapter
+	len() int
+	exportItem(i int) interface{}
 }
 
 type exportCommand struct {
 	object exportable
-	list   exportableAt
+	list   exportableList
 }
 
 func (export exportCommand) run(cmd *cobra.Command, args []string) error {
@@ -79,18 +79,18 @@ func (export exportCommand) run(cmd *cobra.Command, args []string) error {
 	}
 
 	if exportAll {
-		err = kubeClient.List(ctx, export.list.AsClientObject(), client.InNamespace(namespace))
+		err = kubeClient.List(ctx, export.list.asRuntimeObject(), client.InNamespace(namespace))
 		if err != nil {
 			return err
 		}
 
-		if export.list.Len() == 0 {
+		if export.list.len() == 0 {
 			logger.Failuref("no objects found in %s namespace", namespace)
 			return nil
 		}
 
-		for i := 0; i < export.list.Len(); i++ {
-			if err = printExport(export.list.ExportAt(i)); err != nil {
+		for i := 0; i < export.list.len(); i++ {
+			if err = printExport(export.list.exportItem(i)); err != nil {
 				return err
 			}
 		}
@@ -100,11 +100,11 @@ func (export exportCommand) run(cmd *cobra.Command, args []string) error {
 			Namespace: namespace,
 			Name:      name,
 		}
-		err = kubeClient.Get(ctx, namespacedName, export.object.AsClientObject())
+		err = kubeClient.Get(ctx, namespacedName, export.object.asRuntimeObject())
 		if err != nil {
 			return err
 		}
-		return printExport(export.object.Export())
+		return printExport(export.object.export())
 	}
 	return nil
 }

cmd/flux/export_auto_imagepolicy.go

@@ -19,7 +19,6 @@ package main
 import (
 	"github.com/spf13/cobra"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-	"k8s.io/apimachinery/pkg/runtime"
 
 	imagev1 "github.com/fluxcd/image-reflector-controller/api/v1alpha1"
 )
@@ -35,8 +34,8 @@ var exportImagePolicyCmd = &cobra.Command{
   flux export auto image-policy alpine1x > alpine1x.yaml
 `,
 	RunE: exportCommand{
-		object: exportableImagePolicy{&imagev1.ImagePolicy{}},
-		list:   exportableImagePolicyList{&imagev1.ImagePolicyList{}},
+		object: imagePolicyAdapter{&imagev1.ImagePolicy{}},
+		list:   imagePolicyListAdapter{&imagev1.ImagePolicyList{}},
 	}.run,
 }
 
@@ -64,30 +63,10 @@ func exportImagePolicy(item *imagev1.ImagePolicy) interface{} {
 	return export
 }
 
-type exportableImagePolicy struct {
-	policy *imagev1.ImagePolicy
+func (ex imagePolicyAdapter) export() interface{} {
+	return exportImagePolicy(ex.ImagePolicy)
 }
 
-func (ex exportableImagePolicy) AsClientObject() runtime.Object {
-	return ex.policy
-}
-
-func (ex exportableImagePolicy) Export() interface{} {
-	return exportImagePolicy(ex.policy)
-}
-
-type exportableImagePolicyList struct {
-	list *imagev1.ImagePolicyList
-}
-
-func (ex exportableImagePolicyList) AsClientObject() runtime.Object {
-	return ex.list
-}
-
-func (ex exportableImagePolicyList) Len() int {
-	return len(ex.list.Items)
-}
-
-func (ex exportableImagePolicyList) ExportAt(i int) interface{} {
-	return exportImagePolicy(&ex.list.Items[i])
+func (ex imagePolicyListAdapter) exportItem(i int) interface{} {
+	return exportImagePolicy(&ex.ImagePolicyList.Items[i])
 }

cmd/flux/export_auto_imagerepository.go

@@ -19,7 +19,6 @@ package main
 import (
 	"github.com/spf13/cobra"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-	"k8s.io/apimachinery/pkg/runtime"
 
 	imagev1 "github.com/fluxcd/image-reflector-controller/api/v1alpha1"
 )
@@ -35,8 +34,8 @@ var exportImageRepositoryCmd = &cobra.Command{
   flux export auto image-repository alpine > alpine.yaml
 `,
 	RunE: exportCommand{
-		object: exportableImageRepository{&imagev1.ImageRepository{}},
-		list:   exportableImageRepositoryList{&imagev1.ImageRepositoryList{}},
+		object: imageRepositoryAdapter{&imagev1.ImageRepository{}},
+		list:   imageRepositoryListAdapter{&imagev1.ImageRepositoryList{}},
 	}.run,
 }
 
@@ -62,30 +61,10 @@ func exportImageRepository(repo *imagev1.ImageRepository) interface{} {
 	return export
 }
 
-type exportableImageRepository struct {
-	repo *imagev1.ImageRepository
+func (ex imageRepositoryAdapter) export() interface{} {
+	return exportImageRepository(ex.ImageRepository)
 }
 
-func (ex exportableImageRepository) AsClientObject() runtime.Object {
-	return ex.repo
-}
-
-func (ex exportableImageRepository) Export() interface{} {
-	return exportImageRepository(ex.repo)
-}
-
-type exportableImageRepositoryList struct {
-	list *imagev1.ImageRepositoryList
-}
-
-func (ex exportableImageRepositoryList) AsClientObject() runtime.Object {
-	return ex.list
-}
-
-func (ex exportableImageRepositoryList) Len() int {
-	return len(ex.list.Items)
-}
-
-func (ex exportableImageRepositoryList) ExportAt(i int) interface{} {
-	return exportImageRepository(&ex.list.Items[i])
+func (ex imageRepositoryListAdapter) exportItem(i int) interface{} {
+	return exportImageRepository(&ex.ImageRepositoryList.Items[i])
 }

cmd/flux/export_auto_imageupdateauto.go

@@ -19,7 +19,6 @@ package main
 import (
 	"github.com/spf13/cobra"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-	"k8s.io/apimachinery/pkg/runtime"
 
 	autov1 "github.com/fluxcd/image-automation-controller/api/v1alpha1"
 )
@@ -35,8 +34,8 @@ var exportImageUpdateCmd = &cobra.Command{
   flux export auto image-update latest-images > latest.yaml
 `,
 	RunE: exportCommand{
-		object: exportableImageUpdate{&autov1.ImageUpdateAutomation{}},
-		list:   exportableImageUpdateList{&autov1.ImageUpdateAutomationList{}},
+		object: imageUpdateAutomationAdapter{&autov1.ImageUpdateAutomation{}},
+		list:   imageUpdateAutomationListAdapter{&autov1.ImageUpdateAutomationList{}},
 	}.run,
 }
 
@@ -64,30 +63,10 @@ func exportImageUpdate(item *autov1.ImageUpdateAutomation) interface{} {
 	return export
 }
 
-type exportableImageUpdate struct {
-	update *autov1.ImageUpdateAutomation
+func (ex imageUpdateAutomationAdapter) export() interface{} {
+	return exportImageUpdate(ex.ImageUpdateAutomation)
 }
 
-func (ex exportableImageUpdate) AsClientObject() runtime.Object {
-	return ex.update
-}
-
-func (ex exportableImageUpdate) Export() interface{} {
-	return exportImageUpdate(ex.update)
-}
-
-type exportableImageUpdateList struct {
-	list *autov1.ImageUpdateAutomationList
-}
-
-func (ex exportableImageUpdateList) AsClientObject() runtime.Object {
-	return ex.list
-}
-
-func (ex exportableImageUpdateList) Len() int {
-	return len(ex.list.Items)
-}
-
-func (ex exportableImageUpdateList) ExportAt(i int) interface{} {
-	return exportImageUpdate(&ex.list.Items[i])
+func (ex imageUpdateAutomationListAdapter) exportItem(i int) interface{} {
+	return exportImageUpdate(&ex.ImageUpdateAutomationList.Items[i])
 }

cmd/flux/get.go

@@ -45,10 +45,10 @@ func init() {
 }
 
 type summarisable interface {
-	objectContainer
-	Len() int
-	SummariseAt(i int, includeNamespace bool) []string
-	Headers(includeNamespace bool) []string
+	adapter
+	len() int
+	summariseItem(i int, includeNamespace bool) []string
+	headers(includeNamespace bool) []string
 }
 
 // --- these help with implementations of summarisable
@@ -92,20 +92,20 @@ func (get getCommand) run(cmd *cobra.Command, args []string) error {
 	if !allNamespaces {
 		listOpts = append(listOpts, client.InNamespace(namespace))
 	}
-	err = kubeClient.List(ctx, get.list.AsClientObject(), listOpts...)
+	err = kubeClient.List(ctx, get.list.asRuntimeObject(), listOpts...)
 	if err != nil {
 		return err
 	}
 
-	if get.list.Len() == 0 {
+	if get.list.len() == 0 {
 		logger.Failuref("no imagerepository objects found in %s namespace", namespace)
 		return nil
 	}
 
-	header := get.list.Headers(allNamespaces)
+	header := get.list.headers(allNamespaces)
 	var rows [][]string
-	for i := 0; i < get.list.Len(); i++ {
-		row := get.list.SummariseAt(i, allNamespaces)
+	for i := 0; i < get.list.len(); i++ {
+		row := get.list.summariseItem(i, allNamespaces)
 		rows = append(rows, row)
 	}
 	utils.PrintTable(os.Stdout, header, rows)

cmd/flux/get_auto_imagepolicy.go

@@ -18,7 +18,6 @@ package main
 
 import (
 	"github.com/spf13/cobra"
-	"k8s.io/apimachinery/pkg/runtime"
 
 	imagev1 "github.com/fluxcd/image-reflector-controller/api/v1alpha1"
 )
@@ -34,7 +33,7 @@ var getImagePolicyCmd = &cobra.Command{
   flux get auto image-policy --all-namespaces
 `,
 	RunE: getCommand{
-		list: &imagePolicySummary{&imagev1.ImagePolicyList{}},
+		list: &imagePolicyListAdapter{&imagev1.ImagePolicyList{}},
 	}.run,
 }
 
@@ -42,28 +41,16 @@ func init() {
 	getAutoCmd.AddCommand(getImagePolicyCmd)
 }
 
-type imagePolicySummary struct {
-	*imagev1.ImagePolicyList
-}
-
-func (s imagePolicySummary) Len() int {
-	return len(s.Items)
-}
-
-func (s imagePolicySummary) SummariseAt(i int, includeNamespace bool) []string {
+func (s imagePolicyListAdapter) summariseItem(i int, includeNamespace bool) []string {
 	item := s.Items[i]
 	status, msg := statusAndMessage(item.Status.Conditions)
 	return append(nameColumns(&item, includeNamespace), status, msg, item.Status.LatestImage)
 }
 
-func (s imagePolicySummary) Headers(includeNamespace bool) []string {
+func (s imagePolicyListAdapter) headers(includeNamespace bool) []string {
 	headers := []string{"Name", "Ready", "Message", "Latest image"}
 	if includeNamespace {
 		return append(namespaceHeader, headers...)
 	}
 	return headers
 }
-
-func (s imagePolicySummary) AsClientObject() runtime.Object {
-	return s.ImagePolicyList
-}

cmd/flux/get_auto_imagerepository.go

@@ -22,7 +22,6 @@ import (
 	"time"
 
 	"github.com/spf13/cobra"
-	"k8s.io/apimachinery/pkg/runtime"
 
 	imagev1 "github.com/fluxcd/image-reflector-controller/api/v1alpha1"
 )
@@ -38,7 +37,7 @@ var getImageRepositoryCmd = &cobra.Command{
   flux get auto image-repository --all-namespaces
 `,
 	RunE: getCommand{
-		list: imageRepositorySummary{&imagev1.ImageRepositoryList{}},
+		list: imageRepositoryListAdapter{&imagev1.ImageRepositoryList{}},
 	}.run,
 }
 
@@ -46,15 +45,7 @@ func init() {
 	getAutoCmd.AddCommand(getImageRepositoryCmd)
 }
 
-type imageRepositorySummary struct {
-	*imagev1.ImageRepositoryList
-}
-
-func (s imageRepositorySummary) Len() int {
-	return len(s.Items)
-}
-
-func (s imageRepositorySummary) SummariseAt(i int, includeNamespace bool) []string {
+func (s imageRepositoryListAdapter) summariseItem(i int, includeNamespace bool) []string {
 	item := s.Items[i]
 	status, msg := statusAndMessage(item.Status.Conditions)
 	var lastScan string
@@ -65,14 +56,10 @@ func (s imageRepositorySummary) SummariseAt(i int, includeNamespace bool) []stri
 		status, msg, lastScan, strings.Title(strconv.FormatBool(item.Spec.Suspend)))
 }
 
-func (s imageRepositorySummary) Headers(includeNamespace bool) []string {
+func (s imageRepositoryListAdapter) headers(includeNamespace bool) []string {
 	headers := []string{"Name", "Ready", "Message", "Last scan", "Suspended"}
 	if includeNamespace {
 		return append(namespaceHeader, headers...)
 	}
 	return headers
 }
-
-func (s imageRepositorySummary) AsClientObject() runtime.Object {
-	return s.ImageRepositoryList
-}

cmd/flux/get_auto_imageupdateauto.go

@@ -22,7 +22,6 @@ import (
 	"time"
 
 	"github.com/spf13/cobra"
-	"k8s.io/apimachinery/pkg/runtime"
 
 	autov1 "github.com/fluxcd/image-automation-controller/api/v1alpha1"
 )
@@ -38,7 +37,7 @@ var getImageUpdateCmd = &cobra.Command{
   flux get auto image-update --all-namespaces
 `,
 	RunE: getCommand{
-		list: &imageUpdateSummary{&autov1.ImageUpdateAutomationList{}},
+		list: &imageUpdateAutomationListAdapter{&autov1.ImageUpdateAutomationList{}},
 	}.run,
 }
 
@@ -46,15 +45,7 @@ func init() {
 	getAutoCmd.AddCommand(getImageUpdateCmd)
 }
 
-type imageUpdateSummary struct {
-	*autov1.ImageUpdateAutomationList
-}
-
-func (s imageUpdateSummary) Len() int {
-	return len(s.Items)
-}
-
-func (s imageUpdateSummary) SummariseAt(i int, includeNamespace bool) []string {
+func (s imageUpdateAutomationListAdapter) summariseItem(i int, includeNamespace bool) []string {
 	item := s.Items[i]
 	status, msg := statusAndMessage(item.Status.Conditions)
 	var lastRun string
@@ -64,14 +55,10 @@ func (s imageUpdateSummary) SummariseAt(i int, includeNamespace bool) []string {
 	return append(nameColumns(&item, includeNamespace), status, msg, lastRun, strings.Title(strconv.FormatBool(item.Spec.Suspend)))
 }
 
-func (s imageUpdateSummary) Headers(includeNamespace bool) []string {
+func (s imageUpdateAutomationListAdapter) headers(includeNamespace bool) []string {
 	headers := []string{"Name", "Ready", "Message", "Last run", "Suspended"}
 	if includeNamespace {
 		return append(namespaceHeader, headers...)
 	}
 	return headers
 }
-
-func (s imageUpdateSummary) AsClientObject() runtime.Object {
-	return s.ImageUpdateAutomationList
-}

cmd/flux/object.go

@@ -20,21 +20,21 @@ import (
 	"k8s.io/apimachinery/pkg/runtime"
 )
 
-// objectContainer is an interface for a wrapper or alias from which we
-// can get a controller-runtime deserialisable value. This is used so
-// that you can wrap an API type to give it other useful methods, but
-// still use values of the wrapper with `client.Client`, which only
-// deals with types that have been added to the schema.
-type objectContainer interface {
-	AsClientObject() runtime.Object
+// adapter is an interface for a wrapper or alias from which we can
+// get a controller-runtime deserialisable value. This is used so that
+// you can wrap an API type to give it other useful methods, but still
+// use values of the wrapper with `client.Client`, which only deals
+// with types that have been added to the schema.
+type adapter interface {
+	asRuntimeObject() runtime.Object
 }
 
-// genericContainer is an objectContainer for any runtime.Object. Use
-// this if there are no other methods needed.
-type genericContainer struct {
+// universalAdapter is an adapter for any runtime.Object. Use this if
+// there are no other methods needed.
+type universalAdapter struct {
 	obj runtime.Object
 }
 
-func (c genericContainer) AsClientObject() runtime.Object {
+func (c universalAdapter) asRuntimeObject() runtime.Object {
 	return c.obj
 }