Always populate TemplateParams 'Object' (#249)

## Change Overview

This commit modifies template params creation to always
populate the Object field with the unstructured representation
of the Kubernetes object that is the target of the actionset

This allows writing generic blueprints that can be re-used
across different types of Kubernetes resources and to reference
fields from within the object spec that we do not hoist into
TemplateParams e.g. `.Object.metadata.labels.<foo>`

The change described is contained to `param.go` and `param_test.go`.
The rest of the changes are to the `kube` pkg to allow testing with
a fake dynamic client. 

## Pull request type

Please check the type of change your PR introduces:
- [ ] Work in Progress
- [ ] Refactoring (no functional changes, no api changes)
- [ ] Trival/Minor
- [x] Bugfix
- [ ] Feature
- [ ] Documentation

## Issues

- #247 

## Test Plan

- [ ] Manual
- [x] Unit test
- [ ] E2E

```
$ go test -check.vv
...
OK: 14 passed
PASS
ok  	github.com/kanisterio/kanister/pkg/param	103.201s
```

pkg/controller/controller.go

@@ -33,6 +33,7 @@ import (
 	corev1 "k8s.io/api/core/v1"
 	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/client-go/dynamic"
 	"k8s.io/client-go/kubernetes"
 	"k8s.io/client-go/rest"
 	"k8s.io/client-go/tools/cache"
@@ -54,6 +55,7 @@ type Controller struct {
 	config           *rest.Config
 	crClient         versioned.Interface
 	clientset        kubernetes.Interface
+	dynClient        dynamic.Interface
 	recorder         record.EventRecorder
 	actionSetTombMap sync.Map
 }
@@ -78,8 +80,14 @@ func (c *Controller) StartWatch(ctx context.Context, namespace string) error {
 	if err != nil {
 		return errors.Wrap(err, "failed to get a k8s client")
 	}
+	dynClient, err := dynamic.NewForConfig(c.config)
+	if err != nil {
+		return errors.Wrap(err, "failed to get a k8s dynamic client")
+	}
+
 	c.crClient = crClient
 	c.clientset = clientset
+	c.dynClient = dynClient
 	c.recorder = eventer.NewEventRecorder(c.clientset, "Kanister Controller")
 
 	for cr, o := range map[customresource.CustomResource]runtime.Object{
@@ -360,7 +368,7 @@ func (c *Controller) runAction(ctx context.Context, as *crv1alpha1.ActionSet, aI
 	if err != nil {
 		return errors.WithStack(err)
 	}
-	tp, err := param.New(ctx, c.clientset, c.crClient, action)
+	tp, err := param.New(ctx, c.clientset, c.dynClient, c.crClient, action)
 	if err != nil {
 		return err
 	}

pkg/function/data_test.go

@@ -20,9 +20,11 @@ import (
 	"fmt"
 
 	. "gopkg.in/check.v1"
-	"k8s.io/api/core/v1"
+	v1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/client-go/dynamic/fake"
 	"k8s.io/client-go/kubernetes"
+	k8sscheme "k8s.io/client-go/kubernetes/scheme"
 
 	kanister "github.com/kanisterio/kanister/pkg"
 	crv1alpha1 "github.com/kanisterio/kanister/pkg/apis/cr/v1alpha1"
@@ -296,7 +298,7 @@ func (s *DataSuite) getTemplateParamsAndPVCName(c *C, replicas int32) (*param.Te
 		},
 	}
 
-	tp, err := param.New(ctx, s.cli, s.crCli, as)
+	tp, err := param.New(ctx, s.cli, fake.NewSimpleDynamicClient(k8sscheme.Scheme, ss), s.crCli, as)
 	c.Assert(err, IsNil)
 	tp.Profile = s.profile
 
@@ -528,7 +530,7 @@ func (s *DataSuite) initPVCTemplateParams(c *C, pvc *v1.PersistentVolumeClaim, o
 		},
 		Options: options,
 	}
-	tp, err := param.New(context.Background(), s.cli, s.crCli, as)
+	tp, err := param.New(context.Background(), s.cli, fake.NewSimpleDynamicClient(k8sscheme.Scheme, pvc), s.crCli, as)
 	c.Assert(err, IsNil)
 	tp.Profile = s.profile
 	return tp

pkg/function/e2e_volume_snapshot_test.go

@@ -25,7 +25,9 @@ import (
 	"k8s.io/api/core/v1"
 	k8sresource "k8s.io/apimachinery/pkg/api/resource"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/client-go/dynamic/fake"
 	"k8s.io/client-go/kubernetes"
+	k8sscheme "k8s.io/client-go/kubernetes/scheme"
 
 	kanister "github.com/kanisterio/kanister/pkg"
 	crv1alpha1 "github.com/kanisterio/kanister/pkg/apis/cr/v1alpha1"
@@ -113,7 +115,7 @@ func (s *VolumeSnapshotTestSuite) SetUpTest(c *C) {
 		},
 	}
 
-	tp, err := param.New(ctx, s.cli, s.crCli, as)
+	tp, err := param.New(ctx, s.cli, fake.NewSimpleDynamicClient(k8sscheme.Scheme, ss), s.crCli, as)
 	c.Assert(err, IsNil)
 	s.tp = tp
 

pkg/function/kube_exec_all_test.go

@@ -21,7 +21,9 @@ import (
 	. "gopkg.in/check.v1"
 	"k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/client-go/dynamic/fake"
 	"k8s.io/client-go/kubernetes"
+	k8sscheme "k8s.io/client-go/kubernetes/scheme"
 
 	kanister "github.com/kanisterio/kanister/pkg"
 	crv1alpha1 "github.com/kanisterio/kanister/pkg/apis/cr/v1alpha1"
@@ -122,7 +124,7 @@ func (s *KubeExecAllTest) TestKubeExecAllDeployment(c *C) {
 			Namespace: s.namespace,
 		},
 	}
-	tp, err := param.New(ctx, s.cli, s.crCli, as)
+	tp, err := param.New(ctx, s.cli, fake.NewSimpleDynamicClient(k8sscheme.Scheme, d), s.crCli, as)
 	c.Assert(err, IsNil)
 
 	action := "echo"
@@ -156,7 +158,7 @@ func (s *KubeExecAllTest) TestKubeExecAllStatefulSet(c *C) {
 			Namespace: s.namespace,
 		},
 	}
-	tp, err := param.New(ctx, s.cli, s.crCli, as)
+	tp, err := param.New(ctx, s.cli, fake.NewSimpleDynamicClient(k8sscheme.Scheme, ss), s.crCli, as)
 	c.Assert(err, IsNil)
 
 	action := "echo"

pkg/function/kube_exec_test.go

@@ -20,9 +20,11 @@ import (
 	"strings"
 
 	. "gopkg.in/check.v1"
-	"k8s.io/api/core/v1"
+	v1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/client-go/dynamic/fake"
 	"k8s.io/client-go/kubernetes"
+	k8sscheme "k8s.io/client-go/kubernetes/scheme"
 
 	kanister "github.com/kanisterio/kanister/pkg"
 	crv1alpha1 "github.com/kanisterio/kanister/pkg/apis/cr/v1alpha1"
@@ -151,7 +153,7 @@ func (s *KubeExecTest) TestKubeExec(c *C) {
 			Namespace: s.namespace,
 		},
 	}
-	tp, err := param.New(ctx, s.cli, s.crCli, as)
+	tp, err := param.New(ctx, s.cli, fake.NewSimpleDynamicClient(k8sscheme.Scheme, ss), s.crCli, as)
 	c.Assert(err, IsNil)
 
 	action := "echo"

pkg/function/scale_test.go

@@ -21,7 +21,9 @@ import (
 	. "gopkg.in/check.v1"
 	"k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/client-go/dynamic/fake"
 	"k8s.io/client-go/kubernetes"
+	k8sscheme "k8s.io/client-go/kubernetes/scheme"
 
 	kanister "github.com/kanisterio/kanister/pkg"
 	crv1alpha1 "github.com/kanisterio/kanister/pkg/apis/cr/v1alpha1"
@@ -154,7 +156,7 @@ func (s *ScaleSuite) TestScaleDeployment(c *C) {
 		},
 	}
 	for _, action := range []string{"scaleUp", "echoHello", "scaleDown"} {
-		tp, err := param.New(ctx, s.cli, s.crCli, as)
+		tp, err := param.New(ctx, s.cli, fake.NewSimpleDynamicClient(k8sscheme.Scheme, d), s.crCli, as)
 		c.Assert(err, IsNil)
 		bp := newScaleBlueprint(kind)
 		phases, err := kanister.GetPhases(*bp, action, *tp)
@@ -203,7 +205,7 @@ func (s *ScaleSuite) TestScaleStatefulSet(c *C) {
 	}
 
 	for _, action := range []string{"scaleUp", "echoHello", "scaleDown"} {
-		tp, err := param.New(ctx, s.cli, s.crCli, as)
+		tp, err := param.New(ctx, s.cli, fake.NewSimpleDynamicClient(k8sscheme.Scheme, ss), s.crCli, as)
 		c.Assert(err, IsNil)
 		bp := newScaleBlueprint(kind)
 		phases, err := kanister.GetPhases(*bp, action, *tp)

pkg/kube/unstructured.go

@@ -27,10 +27,15 @@ func FetchUnstructuredObject(resource schema.GroupVersionResource, namespace, na
 	if err != nil {
 		return nil, err
 	}
-	return fetchCR(cli, resource, namespace, name)
+	return FetchUnstructuredObjectWithCli(cli, resource, namespace, name)
 }
 
-func fetchCR(cli dynamic.Interface, resource schema.GroupVersionResource, namespace, name string) (runtime.Unstructured, error) {
+// FetchUnstructuredObjectWithCli returns the referenced API object as a map[string]interface{} using the specified CLI
+// TODO: deprecate `FetchUnstructuredObject`
+func FetchUnstructuredObjectWithCli(cli dynamic.Interface, resource schema.GroupVersionResource, namespace, name string) (runtime.Unstructured, error) {
+	if namespace == "" {
+		cli.Resource(resource).Get(name, metav1.GetOptions{})
+	}
 	return cli.Resource(resource).Namespace(namespace).Get(name, metav1.GetOptions{})
 }
 
@@ -40,12 +45,16 @@ func ListUnstructuredObject(resource schema.GroupVersionResource, namespace stri
 	if err != nil {
 		return nil, err
 	}
-	return listCR(cli, resource, namespace)
+	return ListUnstructuredObjectWithCli(cli, resource, namespace)
 }
 
-func listCR(cli dynamic.Interface, resource schema.GroupVersionResource, namespace string) (runtime.Unstructured, error) {
-	//return cli.Resource(resource).Namespace(namespace).List(metav1.ListOptions{})
-	return cli.Resource(resource).List(metav1.ListOptions{})
+// ListUnstructuredObjectWithCli returns the referenced API objects as a map[string]interface{} using the specified CLI
+// TODO: deprecate `ListUnstructuredObject`
+func ListUnstructuredObjectWithCli(cli dynamic.Interface, resource schema.GroupVersionResource, namespace string) (runtime.Unstructured, error) {
+	if namespace == "" {
+		return cli.Resource(resource).List(metav1.ListOptions{})
+	}
+	return cli.Resource(resource).Namespace(namespace).List(metav1.ListOptions{})
 }
 
 func client() (dynamic.Interface, error) {

pkg/param/param.go

@@ -20,9 +20,10 @@ import (
 	"time"
 
 	"github.com/pkg/errors"
-	"k8s.io/api/core/v1"
+	v1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/client-go/dynamic"
 	"k8s.io/client-go/kubernetes"
 
 	crv1alpha1 "github.com/kanisterio/kanister/pkg/apis/cr/v1alpha1"
@@ -118,7 +119,7 @@ const (
 )
 
 // New function fetches and returns the desired params
-func New(ctx context.Context, cli kubernetes.Interface, crCli versioned.Interface, as crv1alpha1.ActionSpec) (*TemplateParams, error) {
+func New(ctx context.Context, cli kubernetes.Interface, dynCli dynamic.Interface, crCli versioned.Interface, as crv1alpha1.ActionSpec) (*TemplateParams, error) {
 	secrets, err := fetchSecrets(ctx, cli, as.Secrets)
 	if err != nil {
 		return nil, err
@@ -140,40 +141,48 @@ func New(ctx context.Context, cli kubernetes.Interface, crCli versioned.Interfac
 		Time:        now.Format(timeFormat),
 		Options:     as.Options,
 	}
+	var gvr schema.GroupVersionResource
+	namespace := as.Object.Namespace
 	switch strings.ToLower(as.Object.Kind) {
 	case StatefulSetKind:
 		ssp, err := fetchStatefulSetParams(ctx, cli, as.Object.Namespace, as.Object.Name)
 		if err != nil {
 			return nil, err
 		}
 		tp.StatefulSet = ssp
+		gvr = schema.GroupVersionResource{Group: "apps", Version: "v1", Resource: "statefulsets"}
 	case DeploymentKind:
 		dp, err := fetchDeploymentParams(ctx, cli, as.Object.Namespace, as.Object.Name)
 		if err != nil {
 			return nil, err
 		}
 		tp.Deployment = dp
+		gvr = schema.GroupVersionResource{Group: "apps", Version: "v1", Resource: "deployments"}
 	case PVCKind:
 		pp, err := fetchPVCParams(ctx, cli, as.Object.Namespace, as.Object.Name)
 		if err != nil {
 			return nil, err
 		}
 		tp.PVC = pp
+		gvr = schema.GroupVersionResource{Group: "", Version: "v1", Resource: "persistentvolumeclaims"}
 	case NamespaceKind:
 		tp.Namespace = &NamespaceParams{Name: as.Object.Namespace}
+		gvr = schema.GroupVersionResource{Group: "", Version: "v1", Resource: "namespaces"}
+		// `Namespace` is a global resource
+		namespace = ""
 	default:
-		gvr := schema.GroupVersionResource{
+		gvr = schema.GroupVersionResource{
 			Group:    as.Object.Group,
 			Version:  as.Object.APIVersion,
 			Resource: as.Object.Resource,
 		}
-		u, err := kube.FetchUnstructuredObject(gvr, as.Object.Namespace, as.Object.Name)
-		if err != nil {
-			return nil, errors.Wrapf(err, "could not fetch object name: %s, namespace: %s, group: %s, version: %s, resource: %s", as.Object.Name, as.Object.Namespace, gvr.Group, gvr.Version, gvr.Resource)
-		}
-		// TODO: We should set `Object` for all other kinds as well.
-		tp.Object = u.UnstructuredContent()
 	}
+	u, err := kube.FetchUnstructuredObjectWithCli(dynCli, gvr, namespace, as.Object.Name)
+	if err != nil {
+		return nil, errors.Wrapf(err, "could not fetch object name: %s, namespace: %s, group: %s, version: %s, resource: %s", as.Object.Name, namespace, gvr.Group, gvr.Version, gvr.Resource)
+	}
+	tp.Object = u.UnstructuredContent()
+
 	return &tp, nil
 }