Add rollout history

api/v1beta1/common_types.go

@@ -120,6 +120,10 @@ const (
 	// instead of being a source of truth for eventual consistency.
 	// This annotation can be used to inform MachinePool status during in-progress scaling scenarios.
 	ReplicasManagedByAnnotation = "cluster.x-k8s.io/replicas-managed-by"
+
+	// ChangeCauseAnnotation is the annotation set on MachineSets by users to identify the cause of revision changes.
+	// This annotation will be shown when users run `clusterctl alpha rollout history`.
+	ChangeCauseAnnotation = "cluster.x-k8s.io/change-cause"
 )
 
 const (

cmd/clusterctl/client/alpha/rollout.go

@@ -40,6 +40,7 @@ type Rollout interface {
 	ObjectPauser(cluster.Proxy, corev1.ObjectReference) error
 	ObjectResumer(cluster.Proxy, corev1.ObjectReference) error
 	ObjectRollbacker(cluster.Proxy, corev1.ObjectReference, int64) error
+	ObjectViewer(cluster.Proxy, corev1.ObjectReference, int64) error
 }
 
 var _ Rollout = &rollout{}

cmd/clusterctl/client/alpha/rollout_viewer.go

@@ -0,0 +1,108 @@
+/*
+Copyright 2022 The Kubernetes 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 alpha
+
+import (
+	"fmt"
+	"os"
+	"sort"
+	"text/tabwriter"
+
+	"github.com/pkg/errors"
+	"gopkg.in/yaml.v2"
+	corev1 "k8s.io/api/core/v1"
+
+	clusterv1 "sigs.k8s.io/cluster-api/api/v1beta1"
+	"sigs.k8s.io/cluster-api/cmd/clusterctl/client/cluster"
+	logf "sigs.k8s.io/cluster-api/cmd/clusterctl/log"
+	"sigs.k8s.io/cluster-api/internal/controllers/machinedeployment/mdutil"
+)
+
+// ObjectViewer will issue a view on the specified cluster-api resource.
+func (r *rollout) ObjectViewer(proxy cluster.Proxy, ref corev1.ObjectReference, revision int64) error {
+	switch ref.Kind {
+	case MachineDeployment:
+		deployment, err := getMachineDeployment(proxy, ref.Name, ref.Namespace)
+		if err != nil || deployment == nil {
+			return errors.Wrapf(err, "failed to get %v/%v", ref.Kind, ref.Name)
+		}
+		if err := viewMachineDeployment(proxy, deployment, revision); err != nil {
+			return err
+		}
+	default:
+		return errors.Errorf("invalid resource type %q, valid values are %v", ref.Kind, validResourceTypes)
+	}
+	return nil
+}
+
+func viewMachineDeployment(proxy cluster.Proxy, d *clusterv1.MachineDeployment, revision int64) error {
+	log := logf.Log
+	msList, err := getMachineSetsForDeployment(proxy, d)
+	if err != nil {
+		return err
+	}
+
+	if revision < 0 {
+		return errors.Errorf("revision number cannot be negative: %v", revision)
+	}
+
+	// Print details of a specific revision
+	if revision > 0 {
+		ms, err := findMachineDeploymentRevision(revision, msList)
+		if err != nil {
+			return errors.Errorf("unable to find the spcified revision")
+		}
+		output, err := yaml.Marshal(ms.Spec.Template)
+		if err != nil {
+			return err
+		}
+		fmt.Fprint(os.Stdout, string(output))
+		return nil
+	}
+
+	// Print an overview of all revisions
+	// Create a revisionToChangeCause map
+	historyInfo := make(map[int64]string)
+	for _, ms := range msList {
+		v, err := mdutil.Revision(ms)
+		if err != nil {
+			log.V(7).Error(err, fmt.Sprintf("unable to get revision from machineset %s for machinedeployment %s in namespace %s", ms.Name, d.Name, d.Namespace))
+			continue
+		}
+		historyInfo[v] = ms.Annotations[clusterv1.ChangeCauseAnnotation]
+	}
+
+	// Sort the revisions
+	revisions := make([]int64, 0, len(historyInfo))
+	for r := range historyInfo {
+		revisions = append(revisions, r)
+	}
+	sort.Slice(revisions, func(i, j int) bool { return revisions[i] < revisions[j] })
+
+	// Output the revisionToChangeCause map
+	writer := new(tabwriter.Writer)
+	writer.Init(os.Stdout, 0, 8, 2, ' ', 0)
+	fmt.Fprintf(writer, "REVISION\tCHANGE-CAUSE\n")
+	for _, r := range revisions {
+		changeCause := historyInfo[r]
+		if changeCause == "" {
+			changeCause = "<none>"
+		}
+		fmt.Fprintf(writer, "%d\t%s\n", r, changeCause)
+	}
+	return writer.Flush()
+}