Add controller for object statuses

internal/pkg/status/deployment_reporter.go

@@ -0,0 +1,170 @@
+// This file is heavily inspired by Prometheus Operator.
+//
+// Copyright 2022 The prometheus-operator 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 status
+
+import (
+	"context"
+	"fmt"
+	"strings"
+	"time"
+
+	appsv1 "k8s.io/api/apps/v1"
+	v1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/utils/ptr"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+)
+
+type DeploymentReporter struct {
+	Pods        []*Pod
+	deployment  *appsv1.Deployment
+	replicaSets *appsv1.ReplicaSetList
+}
+
+// NewDeploymentReporter returns a deployment's reporter.
+func NewDeploymentReporter(ctx context.Context, c client.Client, deployment *appsv1.Deployment) (*DeploymentReporter, error) {
+	if deployment == nil {
+		// deployment is nil when the controller couldn't create the deployment
+		// (incompatible spec fields for instance).
+		return &DeploymentReporter{
+			Pods: []*Pod{},
+		}, nil
+	}
+
+	ls, err := metav1.LabelSelectorAsSelector(deployment.Spec.Selector)
+	if err != nil {
+		// Something is really broken if the deployment's selector isn't valid.
+		panic(err)
+	}
+
+	pods := &v1.PodList{}
+	if err := c.List(ctx, pods, client.InNamespace(deployment.Namespace), client.MatchingLabelsSelector{Selector: ls}); err != nil {
+		return nil, err
+	}
+
+	replicaSets := &appsv1.ReplicaSetList{}
+	if err := c.List(ctx, replicaSets, client.InNamespace(deployment.Namespace), client.MatchingLabelsSelector{Selector: ls}); err != nil {
+		return nil, err
+	}
+
+	deploymentReporter := &DeploymentReporter{
+		deployment:  deployment,
+		replicaSets: replicaSets,
+		Pods:        make([]*Pod, 0, len(pods.Items)),
+	}
+	for _, p := range pods.Items {
+		var found bool
+		for _, owner := range p.ObjectMeta.OwnerReferences {
+			if owner.Kind == "Deployment" && owner.Name == deployment.Name {
+				found = true
+				break
+			}
+		}
+
+		if !found {
+			continue
+		}
+
+		deploymentReporter.Pods = append(deploymentReporter.Pods, ptr.To(Pod(p)))
+	}
+
+	return deploymentReporter, nil
+}
+
+// UpdatedPods returns the list of pods that match with the deployment's revision.
+func (dr *DeploymentReporter) UpdatedPods() []*Pod {
+	return dr.filterPods(func(p *Pod) bool {
+		return dr.IsUpdated(p)
+	})
+}
+
+// IsUpdated returns true if the given pod matches with the deployment's revision.
+func (dr *DeploymentReporter) IsUpdated(p *Pod) bool {
+	for _, rs := range dr.replicaSets.Items {
+		if rs.Labels["pod-template-hash"] == p.Labels["pod-template-hash"] {
+			if dr.deployment.Annotations["deployment.kubernetes.io/revision"] == rs.Annotations["deployment.kubernetes.io/revision"] {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+// ReadyPods returns the list of pods that are ready.
+func (dr *DeploymentReporter) ReadyPods() []*Pod {
+	return dr.filterPods(func(p *Pod) bool {
+		return p.Ready()
+	})
+}
+
+func (dr *DeploymentReporter) filterPods(f func(*Pod) bool) []*Pod {
+	pods := make([]*Pod, 0, len(dr.Pods))
+
+	for _, p := range dr.Pods {
+		if f(p) {
+			pods = append(pods, p)
+		}
+	}
+
+	return pods
+}
+
+func (dr *DeploymentReporter) Update(gObj GoverningObject) metav1.Condition {
+	condition := metav1.Condition{
+		Type:   "Available",
+		Status: metav1.ConditionTrue,
+		LastTransitionTime: metav1.Time{
+			Time: time.Now().UTC(),
+		},
+		ObservedGeneration: gObj.GetGeneration(),
+	}
+
+	var (
+		ready     = len(dr.ReadyPods())
+		updated   = len(dr.UpdatedPods())
+		available = len(dr.ReadyPods())
+	)
+	gObj.SetReplicas(len(dr.Pods))
+	gObj.SetUpdatedReplicas(updated)
+	gObj.SetAvailableReplicas(ready)
+	gObj.SetUnavailableReplicas(len(dr.Pods) - ready)
+
+	switch {
+	case dr.deployment == nil:
+		condition.Reason = "DeploymentNotFound"
+		condition.Status = metav1.ConditionFalse
+	case ready < gObj.ExpectedReplicas():
+		switch {
+		case available == 0:
+			condition.Reason = "NoPodReady"
+			condition.Status = metav1.ConditionFalse
+		default:
+			condition.Reason = "SomePodsNotReady"
+			condition.Status = "Degraded"
+		}
+	}
+
+	var messages []string
+	for _, p := range dr.Pods {
+		if m := p.Message(); m != "" {
+			messages = append(messages, fmt.Sprintf("pod %s: %s", p.Name, m))
+		}
+	}
+
+	condition.Message = strings.Join(messages, "\n")
+	return condition
+}

internal/pkg/status/interface.go

@@ -0,0 +1,20 @@
+package status
+
+import metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+
+// GoverningObject is an interface that represents a Kubernetes object that can be used to report the status of a StatefulSet or Deployment.
+type GoverningObject interface {
+	metav1.Object
+	ExpectedReplicas() int
+	SetReplicas(int)
+	SetUpdatedReplicas(int)
+	SetAvailableReplicas(int)
+	SetUnavailableReplicas(int)
+}
+
+type Reporter interface {
+	Update(GoverningObject) metav1.Condition
+}
+
+var _ Reporter = &StatefulSetReporter{}
+var _ Reporter = &DeploymentReporter{}

internal/pkg/status/pod.go

@@ -0,0 +1,40 @@
+package status
+
+import v1 "k8s.io/api/core/v1"
+
+// Pod is an alias for the Kubernetes v1.Pod type.
+type Pod v1.Pod
+
+// Ready returns true if the pod is ready.
+func (p *Pod) Ready() bool {
+	if p.Status.Phase != v1.PodRunning {
+		return false
+	}
+
+	for _, cond := range p.Status.Conditions {
+		if cond.Type != v1.PodReady {
+			continue
+		}
+		return cond.Status == v1.ConditionTrue
+	}
+
+	return false
+}
+
+// Message returns a human-readable and terse message about the state of the pod.
+func (p *Pod) Message() string {
+	for _, condType := range []v1.PodConditionType{
+		v1.PodScheduled,    // Check first that the pod is scheduled.
+		v1.PodInitialized,  // Then that init containers have been started successfully.
+		v1.ContainersReady, // Then that all containers are ready.
+		v1.PodReady,        // And finally that the pod is ready.
+	} {
+		for _, cond := range p.Status.Conditions {
+			if cond.Type == condType && cond.Status == v1.ConditionFalse {
+				return cond.Message
+			}
+		}
+	}
+
+	return ""
+}

internal/pkg/status/statefulset_reporter.go

@@ -0,0 +1,157 @@
+// This file is heavily inspired by Prometheus Operator.
+//
+// Copyright 2022 The prometheus-operator 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 status
+
+import (
+	"context"
+	"fmt"
+	"strings"
+	"time"
+
+	appsv1 "k8s.io/api/apps/v1"
+	v1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/utils/ptr"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+)
+
+type StatefulSetReporter struct {
+	Pods []*Pod
+	sset *appsv1.StatefulSet
+}
+
+// NewStatefulSetReporter returns a statefulset's reporter.
+func NewStatefulSetReporter(ctx context.Context, c client.Client, sset *appsv1.StatefulSet) (*StatefulSetReporter, error) {
+	if sset == nil {
+		// sset is nil when the controller couldn't create the statefulset
+		// (incompatible spec fields for instance).
+		return &StatefulSetReporter{
+			Pods: []*Pod{},
+		}, nil
+	}
+
+	ls, err := metav1.LabelSelectorAsSelector(sset.Spec.Selector)
+	if err != nil {
+		// Something is really broken if the statefulset's selector isn't valid.
+		panic(err)
+	}
+
+	pods := &v1.PodList{}
+	if err := c.List(ctx, pods, client.InNamespace(sset.Namespace), client.MatchingLabelsSelector{Selector: ls}); err != nil {
+		return nil, err
+	}
+
+	stsReporter := &StatefulSetReporter{
+		sset: sset,
+		Pods: make([]*Pod, 0, len(pods.Items)),
+	}
+	for _, p := range pods.Items {
+		var found bool
+		for _, owner := range p.ObjectMeta.OwnerReferences {
+			if owner.Kind == "StatefulSet" && owner.Name == sset.Name {
+				found = true
+				break
+			}
+		}
+
+		if !found {
+			continue
+		}
+
+		stsReporter.Pods = append(stsReporter.Pods, ptr.To(Pod(p)))
+	}
+
+	return stsReporter, nil
+}
+
+// UpdatedPods returns the list of pods that match with the statefulset's revision.
+func (sr *StatefulSetReporter) UpdatedPods() []*Pod {
+	return sr.filterPods(func(p *Pod) bool {
+		return sr.IsUpdated(p)
+	})
+}
+
+// IsUpdated returns true if the given pod matches with the statefulset's revision.
+func (sr *StatefulSetReporter) IsUpdated(p *Pod) bool {
+	return sr.sset.Status.UpdateRevision == p.Labels["controller-revision-hash"]
+}
+
+// ReadyPods returns the list of pods that are ready.
+func (sr *StatefulSetReporter) ReadyPods() []*Pod {
+	return sr.filterPods(func(p *Pod) bool {
+		return p.Ready()
+	})
+}
+
+func (sr *StatefulSetReporter) filterPods(f func(*Pod) bool) []*Pod {
+	pods := make([]*Pod, 0, len(sr.Pods))
+
+	for _, p := range sr.Pods {
+		if f(p) {
+			pods = append(pods, p)
+		}
+	}
+
+	return pods
+}
+
+func (sr *StatefulSetReporter) Update(gObj GoverningObject) metav1.Condition {
+	condition := metav1.Condition{
+		Type:   "Available",
+		Status: metav1.ConditionTrue,
+		LastTransitionTime: metav1.Time{
+			Time: time.Now().UTC(),
+		},
+		ObservedGeneration: gObj.GetGeneration(),
+	}
+
+	var (
+		ready     = len(sr.ReadyPods())
+		updated   = len(sr.UpdatedPods())
+		available = len(sr.ReadyPods())
+	)
+	gObj.SetReplicas(len(sr.Pods))
+	gObj.SetUpdatedReplicas(updated)
+	gObj.SetAvailableReplicas(ready)
+	gObj.SetUnavailableReplicas(len(sr.Pods) - ready)
+
+	switch {
+	case sr.sset == nil:
+		condition.Reason = "StatefulSetNotFound"
+		condition.Status = metav1.ConditionFalse
+	case ready < gObj.ExpectedReplicas():
+		switch {
+		case available == 0:
+			condition.Reason = "NoPodReady"
+			condition.Status = metav1.ConditionFalse
+		default:
+			condition.Reason = "SomePodsNotReady"
+			condition.Status = "Degraded"
+		}
+	}
+
+	var messages []string
+	for _, p := range sr.Pods {
+		if m := p.Message(); m != "" {
+			messages = append(messages, fmt.Sprintf("pod %s: %s", p.Name, m))
+		}
+	}
+
+	condition.Message = strings.Join(messages, "\n")
+
+	return condition
+}