add "kn service export" (#653)

CHANGELOG.adoc

@@ -63,6 +63,10 @@
 | 🎁
 | Add `--user` flag for specifying the user id to run the container
 | https://github.com/knative/client/pull/679[#679]
+
+| 🎁
+| add kn service export command for exporting a service
+| https://github.com/knative/client/pull/669[#669]
 |===
 
 ## v0.12.0 (2020-01-29)

docs/cmd/kn_service.md

@@ -30,6 +30,7 @@ kn service [flags]
 * [kn service create](kn_service_create.md)	 - Create a service.
 * [kn service delete](kn_service_delete.md)	 - Delete a service.
 * [kn service describe](kn_service_describe.md)	 - Show details of a service
+* [kn service export](kn_service_export.md)	 - export a service
 * [kn service list](kn_service_list.md)	 - List available services.
 * [kn service update](kn_service_update.md)	 - Update a service.
 

docs/cmd/kn_service_export.md

@@ -0,0 +1,45 @@
+## kn service export
+
+export a service
+
+### Synopsis
+
+export a service
+
+```
+kn service export NAME [flags]
+```
+
+### Examples
+
+```
+
+  # Export a service in yaml format
+  kn service export foo -n bar -o yaml
+  # Export a service in json format
+  kn service export foo -n bar -o json
+```
+
+### Options
+
+```
+      --allow-missing-template-keys   If true, ignore any errors in templates when a field or map key is missing in the template. Only applies to golang and jsonpath output formats. (default true)
+  -h, --help                          help for export
+  -r, --history                       Export all active revisions
+  -n, --namespace string              Specify the namespace to operate in.
+  -o, --output string                 Output format. One of: json|yaml|name|go-template|go-template-file|template|templatefile|jsonpath|jsonpath-file.
+      --template string               Template string or path to template file to use when -o=go-template, -o=go-template-file. The template format is golang templates [http://golang.org/pkg/text/template/#pkg-overview].
+```
+
+### Options inherited from parent commands
+
+```
+      --config string       kn config file (default is ~/.config/kn/config.yaml)
+      --kubeconfig string   kubectl config file (default is ~/.kube/config)
+      --log-http            log http traffic
+```
+
+### SEE ALSO
+
+* [kn service](kn_service.md)	 - Service command group
+

pkg/kn/commands/service/export.go

@@ -0,0 +1,230 @@
+// Copyright © 2020 The Knative 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 service
+
+import (
+	"errors"
+	"fmt"
+
+	"sort"
+	"strconv"
+
+	"github.com/spf13/cobra"
+
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/cli-runtime/pkg/genericclioptions"
+
+	"knative.dev/client/pkg/kn/commands"
+	clientservingv1 "knative.dev/client/pkg/serving/v1"
+	"knative.dev/serving/pkg/apis/serving"
+	servingv1 "knative.dev/serving/pkg/apis/serving/v1"
+)
+
+// NewServiceExportCommand returns a new command for exporting a service.
+func NewServiceExportCommand(p *commands.KnParams) *cobra.Command {
+
+	// For machine readable output
+	machineReadablePrintFlags := genericclioptions.NewPrintFlags("")
+
+	command := &cobra.Command{
+		Use:   "export NAME",
+		Short: "export a service",
+		Example: `
+  # Export a service in yaml format
+  kn service export foo -n bar -o yaml
+  # Export a service in json format
+  kn service export foo -n bar -o json`,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			if len(args) != 1 {
+				return errors.New("'kn service export' requires name of the service as single argument")
+			}
+			if !machineReadablePrintFlags.OutputFlagSpecified() {
+				return errors.New("'kn service export' requires output format")
+			}
+			serviceName := args[0]
+
+			namespace, err := p.GetNamespace(cmd)
+			if err != nil {
+				return err
+			}
+
+			client, err := p.NewServingClient(namespace)
+			if err != nil {
+				return err
+			}
+
+			service, err := client.GetService(serviceName)
+			if err != nil {
+				return err
+			}
+
+			history, err := cmd.Flags().GetBool("history")
+			if err != nil {
+				return err
+			}
+
+			printer, err := machineReadablePrintFlags.ToPrinter()
+			if err != nil {
+				return err
+			}
+
+			if history {
+				if svcList, err := exportServicewithActiveRevisions(service, client); err != nil {
+					return err
+				} else {
+					return printer.PrintObj(svcList, cmd.OutOrStdout())
+				}
+			}
+			return printer.PrintObj(exportService(service), cmd.OutOrStdout())
+		},
+	}
+	flags := command.Flags()
+	commands.AddNamespaceFlags(flags, false)
+	flags.BoolP("history", "r", false, "Export all active revisions")
+	machineReadablePrintFlags.AddFlags(command)
+	return command
+}
+
+func exportService(latestSvc *servingv1.Service) *servingv1.Service {
+
+	exportedSvc := servingv1.Service{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:   latestSvc.ObjectMeta.Name,
+			Labels: latestSvc.ObjectMeta.Labels,
+		},
+		TypeMeta: latestSvc.TypeMeta,
+	}
+
+	exportedSvc.Spec.Template = servingv1.RevisionTemplateSpec{
+		Spec:       latestSvc.Spec.ConfigurationSpec.Template.Spec,
+		ObjectMeta: latestSvc.Spec.ConfigurationSpec.Template.ObjectMeta,
+	}
+
+	return &exportedSvc
+}
+
+func constructServicefromRevision(latestSvc *servingv1.Service, revision servingv1.Revision) servingv1.Service {
+
+	exportedSvc := servingv1.Service{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:   latestSvc.ObjectMeta.Name,
+			Labels: latestSvc.ObjectMeta.Labels,
+		},
+		TypeMeta: latestSvc.TypeMeta,
+	}
+
+	exportedSvc.Spec.Template = servingv1.RevisionTemplateSpec{
+		Spec:       revision.Spec,
+		ObjectMeta: latestSvc.Spec.ConfigurationSpec.Template.ObjectMeta,
+	}
+
+	exportedSvc.Spec.ConfigurationSpec.Template.ObjectMeta.Name = revision.ObjectMeta.Name
+
+	return exportedSvc
+}
+
+func exportServicewithActiveRevisions(latestSvc *servingv1.Service, client clientservingv1.KnServingClient) (*servingv1.ServiceList, error) {
+	var exportedSvcItems []servingv1.Service
+
+	//get revisions to export from traffic
+	revsMap := getRevisionstoExport(latestSvc)
+
+	var params []clientservingv1.ListConfig
+	params = append(params, clientservingv1.WithService(latestSvc.ObjectMeta.Name))
+
+	// Query for list with filters
+	revisionList, err := client.ListRevisions(params...)
+	if err != nil {
+		return nil, err
+	}
+	if len(revisionList.Items) == 0 {
+		return nil, fmt.Errorf("No revisions found for the service %s", latestSvc.ObjectMeta.Name)
+	}
+
+	// sort revisions to main the order of generations
+	sortRevisions(revisionList)
+
+	for _, revision := range revisionList.Items {
+		//construct service only for active revisions
+		if revsMap[revision.ObjectMeta.Name] {
+			exportedSvcItems = append(exportedSvcItems, constructServicefromRevision(latestSvc, revision))
+		}
+	}
+
+	//set traffic in the latest revision
+	exportedSvcItems[len(exportedSvcItems)-1] = setTrafficSplit(latestSvc, exportedSvcItems[len(exportedSvcItems)-1])
+
+	typeMeta := metav1.TypeMeta{
+		APIVersion: "v1",
+		Kind:       "List",
+	}
+	exportedSvcList := &servingv1.ServiceList{
+		TypeMeta: typeMeta,
+		Items:    exportedSvcItems,
+	}
+
+	return exportedSvcList, nil
+}
+
+func setTrafficSplit(latestSvc *servingv1.Service, exportedSvc servingv1.Service) servingv1.Service {
+
+	exportedSvc.Spec.RouteSpec = latestSvc.Spec.RouteSpec
+
+	return exportedSvc
+}
+
+func getRevisionstoExport(latestSvc *servingv1.Service) map[string]bool {
+	trafficList := latestSvc.Spec.RouteSpec.Traffic
+	revsMap := make(map[string]bool)
+
+	for _, traffic := range trafficList {
+		if traffic.RevisionName == "" {
+			revsMap[latestSvc.Spec.ConfigurationSpec.Template.ObjectMeta.Name] = true
+		} else {
+			revsMap[traffic.RevisionName] = true
+		}
+	}
+	return revsMap
+}
+
+// sortRevisions sorts revisions by generation and name (in this order)
+func sortRevisions(revisionList *servingv1.RevisionList) {
+	// sort revisionList by configuration generation key
+	sort.SliceStable(revisionList.Items, revisionListSortFunc(revisionList))
+}
+
+// revisionListSortFunc sorts by generation and name
+func revisionListSortFunc(revisionList *servingv1.RevisionList) func(i int, j int) bool {
+	return func(i, j int) bool {
+		a := revisionList.Items[i]
+		b := revisionList.Items[j]
+
+		// By Generation
+		// Convert configuration generation key from string to int for avoiding string comparison.
+		agen, err := strconv.Atoi(a.Labels[serving.ConfigurationGenerationLabelKey])
+		if err != nil {
+			return a.Name > b.Name
+		}
+		bgen, err := strconv.Atoi(b.Labels[serving.ConfigurationGenerationLabelKey])
+		if err != nil {
+			return a.Name > b.Name
+		}
+
+		if agen != bgen {
+			return agen < bgen
+		}
+		return a.Name > b.Name
+	}
+}