add revision describe (knative#15)

* print the yaml formatted revision by default
* allow for custom formatting to be passed in

pkg/kn/commands/revision.go

@@ -25,5 +25,6 @@ func NewRevisionCommand(p *KnParams) *cobra.Command {
 	}
 	revisionCmd.PersistentFlags().StringP("namespace", "n", "default", "Namespace to use.")
 	revisionCmd.AddCommand(NewRevisionListCommand(p))
+	revisionCmd.AddCommand(NewRevisionDescribeCommand(p))
 	return revisionCmd
 }

pkg/kn/commands/revision_describe.go

@@ -0,0 +1,65 @@
+// Copyright © 2018 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 commands
+
+import (
+	"errors"
+
+	"github.com/spf13/cobra"
+	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/cli-runtime/pkg/genericclioptions"
+)
+
+var revisionDescribePrintFlags *genericclioptions.PrintFlags
+
+func NewRevisionDescribeCommand(p *KnParams) *cobra.Command {
+	revisionDescribePrintFlags := genericclioptions.NewPrintFlags("").WithDefaultOutput("yaml")
+	revisionDescribeCmd := &cobra.Command{
+		Use:   "describe NAME",
+		Short: "Describe revisions.",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			client, err := p.ServingFactory()
+			if err != nil {
+				return err
+			}
+			namespace := cmd.Flag("namespace").Value.String()
+
+			if len(args) < 1 {
+				return errors.New("requires the revision name.")
+			}
+			revision, err := client.Revisions(namespace).Get(args[0], v1.GetOptions{})
+			if err != nil {
+				return err
+			}
+
+			printer, err := revisionDescribePrintFlags.ToPrinter()
+			if err != nil {
+				return err
+			}
+			revision.GetObjectKind().SetGroupVersionKind(schema.GroupVersionKind{
+				Group:   "knative.dev",
+				Version: "v1alpha1",
+				Kind:    "Revision"})
+			err = printer.PrintObj(revision, cmd.OutOrStdout())
+			if err != nil {
+				return err
+			}
+			return nil
+		},
+	}
+	revisionDescribePrintFlags.AddFlags(revisionDescribeCmd)
+	return revisionDescribeCmd
+}

pkg/kn/commands/revision_describe_test.go

@@ -0,0 +1,105 @@
+// Copyright © 2018 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 commands
+
+import (
+	"bytes"
+	"encoding/json"
+	"testing"
+
+	"github.com/knative/serving/pkg/apis/serving/v1alpha1"
+	serving "github.com/knative/serving/pkg/client/clientset/versioned/typed/serving/v1alpha1"
+	"github.com/knative/serving/pkg/client/clientset/versioned/typed/serving/v1alpha1/fake"
+	corev1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/api/equality"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	client_testing "k8s.io/client-go/testing"
+	"sigs.k8s.io/yaml"
+)
+
+func fakeRevision(args []string, response *v1alpha1.Revision) (action client_testing.Action, output string, err error) {
+	buf := new(bytes.Buffer)
+	fakeServing := &fake.FakeServingV1alpha1{&client_testing.Fake{}}
+	cmd := NewKnCommand(KnParams{
+		Output:         buf,
+		ServingFactory: func() (serving.ServingV1alpha1Interface, error) { return fakeServing, nil },
+	})
+	fakeServing.AddReactor("*", "*",
+		func(a client_testing.Action) (bool, runtime.Object, error) {
+			action = a
+			return true, response, nil
+		})
+	cmd.SetArgs(args)
+	err = cmd.Execute()
+	if err != nil {
+		return
+	}
+	output = buf.String()
+	return
+}
+
+func TestRevisionWithNoName(t *testing.T) {
+	_, _, err := fakeRevision([]string{"revision", "describe"}, &v1alpha1.Revision{})
+	expectedError := "requires the revision name."
+	if err == nil || err.Error() != expectedError {
+		t.Fatal("expect to fail with missing revision name")
+		return
+	}
+}
+
+func TestRevisionYaml(t *testing.T) {
+	expectedRevision := v1alpha1.Revision{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      "foo",
+			Namespace: "default",
+		},
+		Spec: v1alpha1.RevisionSpec{
+			Container: corev1.Container{
+				Name:  "some-container",
+				Image: "knative/test:latest",
+			},
+		},
+		Status: v1alpha1.RevisionStatus{
+			ServiceName: "foo-service",
+		},
+	}
+
+	action, data, err := fakeRevision([]string{"revision", "describe", "test-rev"}, &expectedRevision)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if action == nil {
+		t.Fatal("No action")
+	} else if !action.Matches("get", "revisions") {
+		t.Fatalf("Bad action %v", action)
+	}
+
+	jsonData, err := yaml.YAMLToJSON([]byte(data))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var returnedRevision v1alpha1.Revision
+	err = json.Unmarshal(jsonData, &returnedRevision)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !equality.Semantic.DeepEqual(expectedRevision, returnedRevision) {
+		t.Fatal("mismatched objects")
+	}
+}