Add OAM workload translators

Signed-off-by: hasheddan <georgedanielmangum@gmail.com>

pkg/oam/trait/modify.go

@@ -41,7 +41,8 @@ var (
 	deploymentKind = reflect.TypeOf(appsv1.Deployment{}).Name()
 )
 
-// DeploymentFromKubeAppAccessor gets deployments from a KubernetesApplication.
+// DeploymentFromKubeAppAccessor finds deployments in a KubernetesApplication
+// and applies the supplied modifier function to them.
 func DeploymentFromKubeAppAccessor(ctx context.Context, obj runtime.Object, t resource.Trait, m trait.ModifyFn) error {
 	a, ok := obj.(*workloadv1alpha1.KubernetesApplication)
 	if !ok {

pkg/oam/workload/apply.go

@@ -0,0 +1,92 @@
+/*
+Copyright 2020 The Crossplane 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 workload
+
+import (
+	"context"
+	"encoding/json"
+
+	jsonpatch "github.com/evanphx/json-patch"
+	"github.com/pkg/errors"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+
+	"github.com/crossplane/crossplane-runtime/pkg/resource"
+
+	workloadv1alpha1 "github.com/crossplane/crossplane/apis/workload/v1alpha1"
+)
+
+var (
+	errNotKubeApp            = "object is not a KubernetesApplication"
+	errMergeKubeAppTemplates = "cannot merge KubernetesApplicationResourceTemplates"
+)
+
+type template struct {
+	gvk  schema.GroupVersionKind
+	name string
+}
+
+// KubeAppApplyOption ensures resource templates are merged instead of replaced
+// before patch if they have the same name and GroupVersionKind. We must merge
+// the current and desired templates prior to submitting a Patch to the API
+// server because KubernetesApplicationResourceTemplates are stored as an array
+// in the KubernetesApplication. This means that entire templates will be
+// replaced when a single field is different, per
+// https://tools.ietf.org/html/rfc7386. We instead patch each of the resource
+// templates individually before passing along the entire KubernetesApplication
+// to resource.Apply.
+func KubeAppApplyOption() resource.ApplyOption {
+	return func(_ context.Context, current, desired runtime.Object) error {
+		c, ok := current.(*workloadv1alpha1.KubernetesApplication)
+		if !ok {
+			return errors.New(errNotKubeApp)
+		}
+		d, ok := desired.(*workloadv1alpha1.KubernetesApplication)
+		if !ok {
+			return errors.New(errNotKubeApp)
+		}
+
+		index := make(map[template]int)
+		for i, t := range d.Spec.ResourceTemplates {
+			temp := &unstructured.Unstructured{}
+			if err := json.Unmarshal(t.Spec.Template.Raw, temp); err != nil {
+				return errors.Wrap(err, errMergeKubeAppTemplates)
+			}
+			index[template{gvk: temp.GroupVersionKind(), name: t.GetName()}] = i
+		}
+
+		for _, t := range c.Spec.ResourceTemplates {
+			temp := &unstructured.Unstructured{}
+			if err := json.Unmarshal(t.Spec.Template.Raw, temp); err != nil {
+				return errors.Wrap(err, errMergeKubeAppTemplates)
+			}
+			i, ok := index[template{gvk: temp.GroupVersionKind(), name: t.GetName()}]
+			if !ok {
+				continue
+			}
+
+			merged, err := jsonpatch.MergePatch(t.Spec.Template.Raw, d.Spec.ResourceTemplates[i].Spec.Template.Raw)
+			if err != nil {
+				return errors.Wrap(err, errMergeKubeAppTemplates)
+			}
+			d.Spec.ResourceTemplates[i].Spec.Template = runtime.RawExtension{Raw: merged}
+		}
+
+		return nil
+	}
+}

pkg/oam/workload/apply_test.go

@@ -0,0 +1,165 @@
+/*
+Copyright 2020 The Crossplane 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 workload
+
+import (
+	"context"
+	"encoding/json"
+	"testing"
+	"time"
+
+	"github.com/google/go-cmp/cmp"
+	"github.com/pkg/errors"
+	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+
+	"github.com/crossplane/crossplane-runtime/pkg/resource"
+	"github.com/crossplane/crossplane-runtime/pkg/test"
+
+	workloadv1alpha1 "github.com/crossplane/crossplane/apis/workload/v1alpha1"
+)
+
+var replicas = int32(3)
+
+type kubeAppModifier func(*workloadv1alpha1.KubernetesApplication)
+
+func kaWithTemplate(name string, o runtime.Object) kubeAppModifier {
+	return func(a *workloadv1alpha1.KubernetesApplication) {
+		b, _ := json.Marshal(o)
+		a.Spec.ResourceTemplates = append(a.Spec.ResourceTemplates, workloadv1alpha1.KubernetesApplicationResourceTemplate{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:              name,
+				CreationTimestamp: metav1.NewTime(time.Date(0, 0, 0, 0, 0, 0, 0, time.Local)),
+			},
+			Spec: workloadv1alpha1.KubernetesApplicationResourceSpec{
+				Template: runtime.RawExtension{Raw: b},
+			},
+		})
+	}
+}
+
+func kubeApp(mod ...kubeAppModifier) *workloadv1alpha1.KubernetesApplication {
+	a := &workloadv1alpha1.KubernetesApplication{
+		ObjectMeta: metav1.ObjectMeta{
+			Name: "cool-kapp",
+		},
+	}
+
+	for _, m := range mod {
+		m(a)
+	}
+
+	return a
+}
+
+var _ resource.ApplyOption = KubeAppApplyOption()
+
+func TestKubeAppApplyOption(t *testing.T) {
+	type args struct {
+		c runtime.Object
+		d runtime.Object
+	}
+
+	type want struct {
+		o   runtime.Object
+		err error
+	}
+
+	cases := map[string]struct {
+		reason string
+		args   args
+		want   want
+	}{
+		"NotAKubernetesApplication": {
+			reason: "An error should be returned if the object is not a KubernetesApplication",
+			args: args{
+				c: &corev1.Namespace{},
+				d: &corev1.Namespace{},
+			},
+			want: want{
+				o:   &corev1.Namespace{},
+				err: errors.New(errNotKubeApp),
+			},
+		},
+		"PatchedNoOverwrite": {
+			reason: "If existing and desired have the same name and kind of a template, non-array fields in templates should not be overwritten in patch",
+			args: args{
+				c: kubeApp(kaWithTemplate("cool-temp", deployment(dmWithReplicas(&replicas)))),
+				d: kubeApp(kaWithTemplate("cool-temp", deployment())),
+			},
+			want: want{
+				o: kubeApp(kaWithTemplate("cool-temp", deployment(dmWithReplicas(&replicas)))),
+			},
+		},
+		"PatchedRemoveResource": {
+			reason: "If existing and desired have different template names, the existing template should be overwritten by the desired",
+			args: args{
+				c: kubeApp(kaWithTemplate("cool-temp", deployment()), kaWithTemplate("nice-temp", deployment())),
+				d: kubeApp(kaWithTemplate("cool-temp", deployment())),
+			},
+			want: want{
+				o: kubeApp(kaWithTemplate("cool-temp", deployment())),
+			},
+		},
+		"PatchedAddResource": {
+			reason: "If existing and desired have different template names, the existing template should be overwritten by the desired",
+			args: args{
+				c: kubeApp(kaWithTemplate("cool-temp", deployment())),
+				d: kubeApp(kaWithTemplate("cool-temp", deployment()), kaWithTemplate("nice-temp", deployment())),
+			},
+			want: want{
+				o: kubeApp(kaWithTemplate("cool-temp", deployment()), kaWithTemplate("nice-temp", deployment())),
+			},
+		},
+		"PatchedOverwrite": {
+			reason: "If existing and desired have different template names, the existing template should be overwritten by the desired",
+			args: args{
+				c: kubeApp(kaWithTemplate("nice-temp", deployment())),
+				d: kubeApp(kaWithTemplate("cool-temp", deployment())),
+			},
+			want: want{
+				o: kubeApp(kaWithTemplate("cool-temp", deployment())),
+			},
+		},
+		"PatchedPartialOverwrite": {
+			reason: "If existing and desired have the same name and kind of a template, array fields in templates should be overwritten in patch",
+			args: args{
+				c: kubeApp(kaWithTemplate("cool-temp", deployment(dmWithReplicas(&replicas), dmWithContainerPorts(replicas)))),
+				d: kubeApp(kaWithTemplate("cool-temp", deployment(dmWithReplicas(&replicas)))),
+			},
+			want: want{
+				o: kubeApp(kaWithTemplate("cool-temp", deployment(dmWithReplicas(&replicas)))),
+			},
+		},
+	}
+
+	for name, tc := range cases {
+		t.Run(name, func(t *testing.T) {
+			err := KubeAppApplyOption()(context.Background(), tc.args.c, tc.args.d)
+			if diff := cmp.Diff(tc.want.err, err, test.EquateErrors()); diff != "" {
+				t.Errorf("\n%s\nKubeAppApplyOption(...): -want error, +got error\n%s\n", tc.reason, diff)
+			}
+
+			o, _ := runtime.DefaultUnstructuredConverter.ToUnstructured(tc.want.o)
+			d, _ := runtime.DefaultUnstructuredConverter.ToUnstructured(tc.args.d)
+			if diff := cmp.Diff(o, d); diff != "" {
+				t.Errorf("\n%s\nKubeAppApplyOption(...): -want, +got\n%s\n", tc.reason, diff)
+			}
+		})
+	}
+}