CLI: Adds reinstall command

This adds reinstall command to install an existing resource again.
If a user install Task A and then change it editing the yaml, then the
user can reinstall the same Task which will bring the Task to orignal.
tkn hub reinstall task <name> [--from=<catalog>] [--version=<version>]
If the task yaml is missing catalog or version label, user will be asked
for it.

Signed-off-by: Shivam Mukhade <smukhade@redhat.com>

api/pkg/cli/cmd/reinstall/reinstall.go

@@ -0,0 +1,249 @@
+// Copyright © 2020 The Tekton 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 reinstall
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/spf13/cobra"
+	"github.com/tektoncd/hub/api/pkg/cli/app"
+	"github.com/tektoncd/hub/api/pkg/cli/flag"
+	"github.com/tektoncd/hub/api/pkg/cli/hub"
+	"github.com/tektoncd/hub/api/pkg/cli/installer"
+	"github.com/tektoncd/hub/api/pkg/cli/kube"
+	"github.com/tektoncd/hub/api/pkg/cli/printer"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+)
+
+const (
+	defaultCatalog = "tekton"
+	catalogLabel   = "hub.tekton.dev/catalog"
+	versionLabel   = "app.kubernetes.io/version"
+)
+
+type options struct {
+	cli      app.CLI
+	from     string
+	version  string
+	kind     string
+	args     []string
+	kc       kube.Config
+	cs       kube.ClientSet
+	hubRes   hub.ResourceResult
+	resource *unstructured.Unstructured
+}
+
+var cmdExamples string = `
+Reinstall a %S of name 'foo':
+
+    tkn hub reinstall %s foo
+
+`
+
+func Command(cli app.CLI) *cobra.Command {
+
+	opts := &options{cli: cli}
+
+	cmd := &cobra.Command{
+		Use:   "reinstall",
+		Short: "Reinstall a resource by its kind and name",
+		Long:  ``,
+		Annotations: map[string]string{
+			"commandType": "main",
+		},
+		SilenceUsage: true,
+	}
+	cmd.AddCommand(
+		commandForKind("task", opts),
+	)
+
+	cmd.PersistentFlags().StringVar(&opts.from, "from", defaultCatalog, "Name of Catalog to which resource belongs.")
+	cmd.PersistentFlags().StringVar(&opts.version, "version", "", "Version of Resource")
+
+	cmd.PersistentFlags().StringVarP(&opts.kc.Path, "kubeconfig", "k", "", "Kubectl config file (default: $HOME/.kube/config)")
+	cmd.PersistentFlags().StringVarP(&opts.kc.Context, "context", "c", "", "Name of the kubeconfig context to use (default: kubectl config current-context)")
+	cmd.PersistentFlags().StringVarP(&opts.kc.Namespace, "namespace", "n", "", "Namespace to use (default: from $KUBECONFIG)")
+
+	return cmd
+}
+
+// commandForKind creates a cobra.Command that when run sets
+// opts.Kind and opts.Args and invokes opts.run
+func commandForKind(kind string, opts *options) *cobra.Command {
+
+	return &cobra.Command{
+		Use:          kind,
+		Short:        "Reinstall " + kind + " from its name",
+		Long:         ``,
+		SilenceUsage: true,
+		Example:      examples(kind),
+		Annotations: map[string]string{
+			"commandType": "main",
+		},
+		Args: cobra.ExactArgs(1),
+		RunE: func(cmd *cobra.Command, args []string) error {
+			opts.kind = kind
+			opts.args = args
+			return opts.run()
+		},
+	}
+}
+
+func (opts *options) run() error {
+
+	if err := opts.validate(); err != nil {
+		return err
+	}
+
+	// This allows fake clients to be inserted while testing
+	var err error
+	if opts.cs == nil {
+		opts.cs, err = kube.NewClientSet(opts.kc)
+		if err != nil {
+			return err
+		}
+	}
+
+	installer := installer.New(opts.cs)
+	opts.resource, err = installer.LookupInstalled(opts.name(), opts.kind, opts.cs.Namespace())
+	if err != nil {
+		if err = opts.lookupError(err); err != nil {
+			return err
+		}
+	}
+
+	catalog, err := opts.resCatalog()
+	if err != nil {
+		return err
+	}
+
+	version, err := opts.resVersion()
+	if err != nil {
+		return err
+	}
+
+	hubClient := opts.cli.Hub()
+	opts.hubRes = hubClient.GetResource(hub.ResourceOption{
+		Name:    opts.name(),
+		Catalog: catalog,
+		Kind:    opts.kind,
+		Version: version,
+	})
+
+	manifest, err := opts.hubRes.Manifest()
+	if err != nil {
+		return err
+	}
+
+	opts.resource, err = installer.Update(manifest, opts.from, opts.cs.Namespace())
+	if err != nil {
+		return opts.errors(err)
+	}
+
+	out := opts.cli.Stream().Out
+	return printer.New(out).String(msg(opts.resource))
+}
+
+func msg(res *unstructured.Unstructured) string {
+	version := res.GetLabels()["app.kubernetes.io/version"]
+	return fmt.Sprintf("%s %s(%s) reinstalled in %s namespace",
+		strings.Title(res.GetKind()), res.GetName(), version, res.GetNamespace())
+}
+
+func (opts *options) validate() error {
+	return flag.ValidateVersion(opts.version)
+}
+
+func (opts *options) name() string {
+	return strings.TrimSpace(opts.args[0])
+}
+
+func (opts *options) lookupError(err error) error {
+
+	if err == installer.ErrNotFound {
+		return fmt.Errorf("%s %s doesn't exists in %s namespace. Use install command to install the resource",
+			strings.Title(opts.kind), opts.name(), opts.cs.Namespace())
+	}
+
+	if err == installer.ErrVersionAndCatalogMissing {
+		if opts.version == "" {
+			return fmt.Errorf("existing resource seems to be missing version and catalog label. Use --version & --catalog (Default: tekton) flag to reinstall the resource")
+		}
+		return nil
+	}
+
+	if err == installer.ErrVersionMissing {
+		if opts.version == "" {
+			return fmt.Errorf("existing resource seems to be missing version label. Use --version flag to reinstall the resource")
+		}
+		return nil
+	}
+
+	// Skip catalog missing error and use default catalog
+	if err == installer.ErrCatalogMissing {
+		return nil
+	}
+
+	return err
+}
+
+func (opts *options) errors(err error) error {
+
+	if strings.Contains(err.Error(), "mutation failed: cannot decode incoming new object") {
+		version, vErr := opts.hubRes.MinPipelinesVersion()
+		if vErr != nil {
+			return vErr
+		}
+		return fmt.Errorf("%v \nMake sure the pipeline version you are running is not lesser than %s and %s have correct spec fields",
+			err, version, opts.kind)
+	}
+	return err
+}
+
+func (opts *options) resCatalog() (string, error) {
+	labels := opts.resource.GetLabels()
+	if len(labels) == 0 {
+		return opts.from, nil
+	}
+	catalog, ok := labels[catalogLabel]
+	if ok {
+		if catalog != opts.from && opts.from != "" {
+			return "", fmt.Errorf("existing resource seems to be from %s catalog, can't reinstall from %s catalog", catalog, opts.from)
+		}
+		return catalog, nil
+	}
+	return opts.from, nil
+}
+
+func (opts *options) resVersion() (string, error) {
+	labels := opts.resource.GetLabels()
+	if len(labels) == 0 {
+		return opts.version, nil
+	}
+	version, ok := labels[versionLabel]
+	if ok {
+		if version != opts.version && opts.version != "" {
+			return "", fmt.Errorf("existing resource seems to be of version %s, can't reinstall version %s", version, opts.version)
+		}
+		return version, nil
+	}
+	return opts.version, nil
+}
+
+func examples(kind string) string {
+	replacer := strings.NewReplacer("%s", kind, "%S", strings.Title(kind))
+	return replacer.Replace(cmdExamples)
+}