Adds shared internal controller certificates apply status func

Signed-off-by: joshvanl <vleeuwenjoshua@gmail.com>

internal/controller/certificates/OWNERS

@@ -0,0 +1,4 @@
+filters:
+  "^apply(_test)?\\.go$":
+    required_reviewers:
+    - joshvanl

internal/controller/certificates/apply.go

@@ -0,0 +1,67 @@
+/*
+Copyright 2020 The cert-manager 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 internal
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+
+	cmclient "github.com/jetstack/cert-manager/pkg/client/clientset/versioned"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	apitypes "k8s.io/apimachinery/pkg/types"
+	"k8s.io/utils/pointer"
+
+	cmapi "github.com/jetstack/cert-manager/pkg/apis/certmanager/v1"
+)
+
+// ApplyStatus will make a Apply API call with the given client to the
+// certificates status sub-resource endpoint. All data in the given Certificate
+// object is dropped; expect for the name, namespace, and status object. The
+// given fieldManager is will be used as the FieldManager in the Apply call.
+// Always sets Force Apply to true.
+func ApplyStatus(ctx context.Context, cl cmclient.Interface, fieldManager string, crt *cmapi.Certificate) error {
+	crtData, err := serializeApplyStatus(crt)
+	if err != nil {
+		return err
+	}
+
+	_, err = cl.CertmanagerV1().Certificates(crt.Namespace).Patch(
+		ctx, crt.Name, apitypes.ApplyPatchType, crtData,
+		metav1.PatchOptions{Force: pointer.Bool(true), FieldManager: fieldManager}, "status",
+	)
+
+	return err
+}
+
+// serializeApplyStatus converts the given Certificate object in JSON. Only the
+// name, namespace, and status field values will be copied and encoded into the
+// serialized slice. All other fields will be left at their zero value.
+// TypeMeta will be populated with the Kind "Certificate" and API Version
+// "cert-manager.io/v1" respectively.
+func serializeApplyStatus(crt *cmapi.Certificate) ([]byte, error) {
+	crt = &cmapi.Certificate{
+		TypeMeta:   metav1.TypeMeta{Kind: cmapi.CertificateKind, APIVersion: cmapi.SchemeGroupVersion.Identifier()},
+		ObjectMeta: metav1.ObjectMeta{Namespace: crt.Namespace, Name: crt.Name},
+		Status:     crt.Status,
+	}
+	crtData, err := json.Marshal(crt)
+	if err != nil {
+		return nil, fmt.Errorf("failed to marshal certificate object: %w", err)
+	}
+	return crtData, nil
+}

internal/controller/certificates/apply_test.go

@@ -0,0 +1,80 @@
+/*
+Copyright 2020 The cert-manager 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 internal
+
+import (
+	"strconv"
+	"sync"
+	"testing"
+
+	fuzz "github.com/google/gofuzz"
+	"github.com/stretchr/testify/assert"
+
+	cmapi "github.com/jetstack/cert-manager/pkg/apis/certmanager/v1"
+)
+
+// This test ensures that when a Certificate object is serialized in
+// preparation for a Certificate status Apply call. Only the required
+// metadata/type fields are present, and only empty spec fields are set. We
+// also ensure that all Certificate status fields are tagged omitempty, and are
+// not serialized if unset.
+func Test_serializeApplyStatus(t *testing.T) {
+	// Expected serialized Certificate Apply object. Should only contain base
+	// meta/type object, empty spec. Status should be matched both via regex, and
+	// when empty.
+	const (
+		expReg   = `^{"kind":"Certificate","apiVersion":"cert-manager.io/v1","metadata":{"name":"foo","namespace":"bar","creationTimestamp":null},"spec":{"secretName":"","issuerRef":{"name":""}},"status":{.*}$`
+		expEmpty = `{"kind":"Certificate","apiVersion":"cert-manager.io/v1","metadata":{"name":"foo","namespace":"bar","creationTimestamp":null},"spec":{"secretName":"","issuerRef":{"name":""}},"status":{}}`
+		numJobs  = 10000
+	)
+
+	var wg sync.WaitGroup
+	jobs := make(chan int)
+
+	wg.Add(numJobs)
+	for i := 0; i < 3; i++ {
+		go func() {
+			for j := range jobs {
+				t.Run("fuzz_"+strconv.Itoa(j), func(t *testing.T) {
+					var crt cmapi.Certificate
+					fuzz.New().NilChance(0.5).Fuzz(&crt)
+					crt.Name = "foo"
+					crt.Namespace = "bar"
+
+					// Test regex with non-empty status.
+					crtData, err := serializeApplyStatus(&crt)
+					assert.NoError(t, err)
+					assert.Regexp(t, expReg, string(crtData))
+
+					// String match on empty status.
+					crt.Status = cmapi.CertificateStatus{}
+					crtData, err = serializeApplyStatus(&crt)
+					assert.NoError(t, err)
+					assert.Equal(t, expEmpty, string(crtData))
+
+					wg.Done()
+				})
+			}
+		}()
+	}
+
+	for i := 0; i < numJobs; i++ {
+		jobs <- i
+	}
+	close(jobs)
+	wg.Wait()
+}