add custom status readers (#314)

internal/kstatus/statusreaders/common.go

@@ -0,0 +1,143 @@
+package statusreaders
+
+import (
+	"context"
+	"errors"
+
+	apierrors "k8s.io/apimachinery/pkg/api/errors"
+	"k8s.io/apimachinery/pkg/api/meta"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/apimachinery/pkg/types"
+	"sigs.k8s.io/cli-utils/pkg/kstatus/polling/engine"
+	"sigs.k8s.io/cli-utils/pkg/kstatus/polling/event"
+	"sigs.k8s.io/cli-utils/pkg/kstatus/status"
+	"sigs.k8s.io/cli-utils/pkg/object"
+)
+
+// baseStatusReader is the implementation of the StatusReader interface defined
+// in the engine package. It contains the basic logic needed for every resource.
+// In order to handle resource specific logic, it must include an implementation
+// of the resourceTypeStatusReader interface.
+// In practice we will create many instances of baseStatusReader, each with a different
+// implementation of the resourceTypeStatusReader interface and therefore each
+// of the instances will be able to handle different resource types.
+type baseStatusReader struct {
+	// mapper provides a way to look up the resource types that are available
+	// in the cluster.
+	mapper meta.RESTMapper
+
+	// resourceStatusReader is an resource-type specific implementation
+	// of the resourceTypeStatusReader interface. While the baseStatusReader
+	// contains the logic shared between all resource types, this implementation
+	// will contain the resource specific info.
+	resourceStatusReader resourceTypeStatusReader
+}
+
+// resourceTypeStatusReader is an interface that can be implemented differently
+// for each resource type.
+type resourceTypeStatusReader interface {
+	Supports(gk schema.GroupKind) bool
+	ReadStatusForObject(ctx context.Context, reader engine.ClusterReader, object *unstructured.Unstructured) (*event.ResourceStatus, error)
+}
+
+func (b *baseStatusReader) Supports(gk schema.GroupKind) bool {
+	return b.resourceStatusReader.Supports(gk)
+}
+
+// ReadStatus reads the object identified by the passed-in identifier and computes it's status. It reads
+// the resource here, but computing status is delegated to the ReadStatusForObject function.
+func (b *baseStatusReader) ReadStatus(ctx context.Context, reader engine.ClusterReader, identifier object.ObjMetadata) (*event.ResourceStatus, error) {
+	object, err := b.lookupResource(ctx, reader, identifier)
+	if err != nil {
+		return errIdentifierToResourceStatus(err, identifier)
+	}
+	return b.resourceStatusReader.ReadStatusForObject(ctx, reader, object)
+}
+
+// ReadStatusForObject computes the status for the passed-in object. Since this is specific for each
+// resource type, the actual work is delegated to the implementation of the resourceTypeStatusReader interface.
+func (b *baseStatusReader) ReadStatusForObject(ctx context.Context, reader engine.ClusterReader, object *unstructured.Unstructured) (*event.ResourceStatus, error) {
+	return b.resourceStatusReader.ReadStatusForObject(ctx, reader, object)
+}
+
+// lookupResource looks up a resource with the given identifier. It will use the rest mapper to resolve
+// the version of the GroupKind given in the identifier.
+// If the resource is found, it is returned. If it is not found or something
+// went wrong, the function will return an error.
+func (b *baseStatusReader) lookupResource(ctx context.Context, reader engine.ClusterReader, identifier object.ObjMetadata) (*unstructured.Unstructured, error) {
+	GVK, err := gvk(identifier.GroupKind, b.mapper)
+	if err != nil {
+		return nil, err
+	}
+
+	var u unstructured.Unstructured
+	u.SetGroupVersionKind(GVK)
+	key := types.NamespacedName{
+		Name:      identifier.Name,
+		Namespace: identifier.Namespace,
+	}
+	err = reader.Get(ctx, key, &u)
+	if err != nil {
+		return nil, err
+	}
+	return &u, nil
+}
+
+// gvk looks up the GVK from a GroupKind using the rest mapper.
+func gvk(gk schema.GroupKind, mapper meta.RESTMapper) (schema.GroupVersionKind, error) {
+	mapping, err := mapper.RESTMapping(gk)
+	if err != nil {
+		return schema.GroupVersionKind{}, err
+	}
+	return mapping.GroupVersionKind, nil
+}
+
+// errResourceToResourceStatus construct the appropriate ResourceStatus
+// object based on an error and the resource itself.
+func errResourceToResourceStatus(err error, resource *unstructured.Unstructured, genResources ...*event.ResourceStatus) (*event.ResourceStatus, error) {
+	// If the error is from the context, we don't attach that to the ResourceStatus,
+	// but just return it directly so the caller can decide how to handle this
+	// situation.
+	if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
+		return nil, err
+	}
+	identifier := object.UnstructuredToObjMetadata(resource)
+	if apierrors.IsNotFound(err) {
+		return &event.ResourceStatus{
+			Identifier: identifier,
+			Status:     status.NotFoundStatus,
+			Message:    "Resource not found",
+		}, nil
+	}
+	return &event.ResourceStatus{
+		Identifier:         identifier,
+		Status:             status.UnknownStatus,
+		Resource:           resource,
+		Error:              err,
+		GeneratedResources: genResources,
+	}, nil
+}
+
+// errIdentifierToResourceStatus construct the appropriate ResourceStatus
+// object based on an error and the identifier for a resource.
+func errIdentifierToResourceStatus(err error, identifier object.ObjMetadata) (*event.ResourceStatus, error) {
+	// If the error is from the context, we don't attach that to the ResourceStatus,
+	// but just return it directly so the caller can decide how to handle this
+	// situation.
+	if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
+		return nil, err
+	}
+	if apierrors.IsNotFound(err) {
+		return &event.ResourceStatus{
+			Identifier: identifier,
+			Status:     status.NotFoundStatus,
+			Message:    "Resource not found",
+		}, nil
+	}
+	return &event.ResourceStatus{
+		Identifier: identifier,
+		Status:     status.UnknownStatus,
+		Error:      err,
+	}, nil
+}

internal/kstatus/statusreaders/default.go

@@ -0,0 +1,84 @@
+package statusreaders
+
+import (
+	"context"
+	"fmt"
+
+	"k8s.io/apimachinery/pkg/api/meta"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"sigs.k8s.io/cli-utils/pkg/kstatus/polling/engine"
+	"sigs.k8s.io/cli-utils/pkg/kstatus/polling/event"
+	"sigs.k8s.io/cli-utils/pkg/kstatus/polling/statusreaders"
+	"sigs.k8s.io/cli-utils/pkg/kstatus/status"
+	"sigs.k8s.io/cli-utils/pkg/object"
+)
+
+// NewDefaultStatusReader returns a DelegatingStatusReader that wraps a list of
+// statusreaders to cover all built-in Kubernetes resources and other CRDs that
+// follow known status conventions.
+func NewDefaultStatusReader(mapper meta.RESTMapper) engine.StatusReader {
+	return NewStatusReader(mapper)
+}
+
+// NewStatusReader returns a DelegatingStatusReader that includes the statusreaders
+// for the build-in Kubernetes resources and also any provided custom status readers.
+func NewStatusReader(mapper meta.RESTMapper, statusReaders ...engine.StatusReader) engine.StatusReader {
+	defaultStatusReader := statusreaders.NewGenericStatusReader(mapper, status.Compute)
+
+	replicaSetStatusReader := NewReplicaSetStatusReader(mapper)
+	deploymentStatusReader := NewDeploymentResourceReader(mapper)
+	statefulSetStatusReader := NewStatefulSetResourceReader(mapper)
+
+	statusReaders = append(statusReaders,
+		deploymentStatusReader,
+		statefulSetStatusReader,
+		replicaSetStatusReader,
+		defaultStatusReader,
+	)
+
+	return &DelegatingStatusReader{
+		StatusReaders: statusReaders,
+	}
+}
+
+type DelegatingStatusReader struct {
+	StatusReaders []engine.StatusReader
+}
+
+func (dsr *DelegatingStatusReader) Supports(gk schema.GroupKind) bool {
+	for _, sr := range dsr.StatusReaders {
+		if sr.Supports(gk) {
+			return true
+		}
+	}
+	return false
+}
+
+func (dsr *DelegatingStatusReader) ReadStatus(
+	ctx context.Context,
+	reader engine.ClusterReader,
+	id object.ObjMetadata,
+) (*event.ResourceStatus, error) {
+	gk := id.GroupKind
+	for _, sr := range dsr.StatusReaders {
+		if sr.Supports(gk) {
+			return sr.ReadStatus(ctx, reader, id)
+		}
+	}
+	return nil, fmt.Errorf("no status reader supports this resource: %v", gk)
+}
+
+func (dsr *DelegatingStatusReader) ReadStatusForObject(
+	ctx context.Context,
+	reader engine.ClusterReader,
+	obj *unstructured.Unstructured,
+) (*event.ResourceStatus, error) {
+	gk := obj.GroupVersionKind().GroupKind()
+	for _, sr := range dsr.StatusReaders {
+		if sr.Supports(gk) {
+			return sr.ReadStatusForObject(ctx, reader, obj)
+		}
+	}
+	return nil, fmt.Errorf("no status reader supports this resource: %v", gk)
+}

internal/kstatus/statusreaders/deployment.go

@@ -0,0 +1,54 @@
+package statusreaders
+
+import (
+	"context"
+
+	appsv1 "k8s.io/api/apps/v1"
+	"k8s.io/apimachinery/pkg/api/meta"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"sigs.k8s.io/cli-utils/pkg/kstatus/polling/engine"
+	"sigs.k8s.io/cli-utils/pkg/kstatus/polling/event"
+	"sigs.k8s.io/cli-utils/pkg/kstatus/status"
+	"sigs.k8s.io/cli-utils/pkg/object"
+)
+
+func NewDeploymentResourceReader(mapper meta.RESTMapper) engine.StatusReader {
+	return &baseStatusReader{
+		mapper: mapper,
+		resourceStatusReader: &deploymentResourceReader{
+			mapper: mapper,
+		},
+	}
+}
+
+// deploymentResourceReader is a resourceTypeStatusReader that can fetch Deployment
+// resources from the cluster, knows how to find any ReplicaSets belonging to the
+// Deployment, and compute status for the deployment.
+type deploymentResourceReader struct {
+	mapper meta.RESTMapper
+}
+
+var _ resourceTypeStatusReader = &deploymentResourceReader{}
+
+func (d *deploymentResourceReader) Supports(gk schema.GroupKind) bool {
+	return gk == appsv1.SchemeGroupVersion.WithKind("Deployment").GroupKind()
+}
+
+func (d *deploymentResourceReader) ReadStatusForObject(_ context.Context, _ engine.ClusterReader,
+	deployment *unstructured.Unstructured) (*event.ResourceStatus, error) {
+	identifier := object.UnstructuredToObjMetadata(deployment)
+
+	res, err := status.Compute(deployment)
+	if err != nil {
+		return errResourceToResourceStatus(err, deployment, []*event.ResourceStatus{}...)
+	}
+
+	return &event.ResourceStatus{
+		Identifier:         identifier,
+		Status:             res.Status,
+		Resource:           deployment,
+		Message:            res.Message,
+		GeneratedResources: []*event.ResourceStatus{},
+	}, nil
+}

internal/kstatus/statusreaders/replicaset.go

@@ -0,0 +1,52 @@
+package statusreaders
+
+import (
+	"context"
+
+	appsv1 "k8s.io/api/apps/v1"
+	"k8s.io/apimachinery/pkg/api/meta"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"sigs.k8s.io/cli-utils/pkg/kstatus/polling/engine"
+	"sigs.k8s.io/cli-utils/pkg/kstatus/polling/event"
+	"sigs.k8s.io/cli-utils/pkg/kstatus/status"
+	"sigs.k8s.io/cli-utils/pkg/object"
+)
+
+func NewReplicaSetStatusReader(mapper meta.RESTMapper) engine.StatusReader {
+	return &baseStatusReader{
+		mapper: mapper,
+		resourceStatusReader: &replicaSetStatusReader{
+			mapper: mapper,
+		},
+	}
+}
+
+// replicaSetStatusReader is an engine that can fetch ReplicaSet resources
+// from the cluster, knows how to find any Pods belonging to the ReplicaSet,
+// and compute status for the ReplicaSet.
+type replicaSetStatusReader struct {
+	mapper meta.RESTMapper
+}
+
+var _ resourceTypeStatusReader = &replicaSetStatusReader{}
+
+func (r *replicaSetStatusReader) Supports(gk schema.GroupKind) bool {
+	return gk == appsv1.SchemeGroupVersion.WithKind("ReplicaSet").GroupKind()
+}
+
+func (r *replicaSetStatusReader) ReadStatusForObject(_ context.Context, _ engine.ClusterReader, rs *unstructured.Unstructured) (*event.ResourceStatus, error) {
+	identifier := object.UnstructuredToObjMetadata(rs)
+	res, err := status.Compute(rs)
+	if err != nil {
+		return errResourceToResourceStatus(err, rs, []*event.ResourceStatus{}...)
+	}
+
+	return &event.ResourceStatus{
+		Identifier:         identifier,
+		Status:             res.Status,
+		Resource:           rs,
+		Message:            res.Message,
+		GeneratedResources: []*event.ResourceStatus{},
+	}, nil
+}

internal/kstatus/statusreaders/statefulset.go

@@ -0,0 +1,53 @@
+package statusreaders
+
+import (
+	"context"
+
+	appsv1 "k8s.io/api/apps/v1"
+	"k8s.io/apimachinery/pkg/api/meta"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"sigs.k8s.io/cli-utils/pkg/kstatus/polling/engine"
+	"sigs.k8s.io/cli-utils/pkg/kstatus/polling/event"
+	"sigs.k8s.io/cli-utils/pkg/kstatus/status"
+	"sigs.k8s.io/cli-utils/pkg/object"
+)
+
+func NewStatefulSetResourceReader(mapper meta.RESTMapper) engine.StatusReader {
+	return &baseStatusReader{
+		mapper: mapper,
+		resourceStatusReader: &statefulSetResourceReader{
+			mapper: mapper,
+		},
+	}
+}
+
+// statefulSetResourceReader is an implementation of the ResourceReader interface
+// that can fetch StatefulSet resources from the cluster, knows how to find any
+// Pods belonging to the StatefulSet, and compute status for the StatefulSet.
+type statefulSetResourceReader struct {
+	mapper meta.RESTMapper
+}
+
+var _ resourceTypeStatusReader = &statefulSetResourceReader{}
+
+func (s *statefulSetResourceReader) Supports(gk schema.GroupKind) bool {
+	return gk == appsv1.SchemeGroupVersion.WithKind("StatefulSet").GroupKind()
+}
+
+func (s *statefulSetResourceReader) ReadStatusForObject(_ context.Context, _ engine.ClusterReader,
+	statefulSet *unstructured.Unstructured) (*event.ResourceStatus, error) {
+	identifier := object.UnstructuredToObjMetadata(statefulSet)
+	res, err := status.Compute(statefulSet)
+	if err != nil {
+		return errResourceToResourceStatus(err, statefulSet, []*event.ResourceStatus{}...)
+	}
+
+	return &event.ResourceStatus{
+		Identifier:         identifier,
+		Status:             res.Status,
+		Resource:           statefulSet,
+		Message:            res.Message,
+		GeneratedResources: []*event.ResourceStatus{},
+	}, nil
+}