Check in some musings on a symmetric key generator controller

There is still a test failing, but I am sure it is a simple fix hiding in the
code. I think this is the general shape of the controller that we want.

Signed-off-by: Andrew Keesler <akeesler@vmware.com>
This commit is contained in:
Andrew Keesler 2020-12-10 11:54:36 -05:00 committed by aram price
parent 3e112fb1ac
commit c3f73ffb57
3 changed files with 461 additions and 0 deletions

1
go.mod
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@ -19,6 +19,7 @@ require (
github.com/ory/fosite v0.35.1
github.com/pkg/browser v0.0.0-20180916011732-0a3d74bf9ce4
github.com/pkg/errors v0.9.1
github.com/prometheus/common v0.10.0
github.com/sclevine/agouti v3.0.0+incompatible
github.com/sclevine/spec v1.4.0
github.com/spf13/cobra v1.0.0

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@ -0,0 +1,166 @@
// Copyright 2020 the Pinniped contributors. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
// Package secretgenerator provides a controller that can ensure existence of a generated secret.
package secretgenerator
import (
"context"
"crypto/rand"
"fmt"
corev1 "k8s.io/api/core/v1"
k8serrors "k8s.io/apimachinery/pkg/api/errors"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
corev1informers "k8s.io/client-go/informers/core/v1"
"k8s.io/client-go/kubernetes"
"k8s.io/client-go/util/retry"
"k8s.io/klog/v2"
pinnipedcontroller "go.pinniped.dev/internal/controller"
"go.pinniped.dev/internal/controllerlib"
"go.pinniped.dev/internal/plog"
)
const (
symmetricKeySecretType = "secrets.pinniped.dev/symmetric"
symmetricKeySecretDataKey = "key"
symmetricKeySize = 32 // TODO: what should this be?
)
// generateKey is stubbed out for the purpose of testing. The default behavior is to generate a symmetric key.
//nolint:gochecknoglobals
var generateKey = generateSymmetricKey
func generateSymmetricKey() ([]byte, error) {
b := make([]byte, symmetricKeySize)
if _, err := rand.Read(b); err != nil {
return nil, err
}
return b, nil
}
type controller struct {
secretNamePrefix string
client kubernetes.Interface
secrets corev1informers.SecretInformer
}
// New instantiates a new controllerlib.Controller which will ensure existence of a generated secret.
func New(secretNamePrefix string, client kubernetes.Interface, secrets corev1informers.SecretInformer) controllerlib.Controller {
c := controller{
secretNamePrefix: secretNamePrefix,
client: client,
secrets: secrets,
}
filter := pinnipedcontroller.SimpleFilterWithSingletonQueue(isOwnee)
return controllerlib.New(
controllerlib.Config{Name: secretNamePrefix + "-secrets-generator", Syncer: &c},
controllerlib.WithInformer(secrets, filter, controllerlib.InformerOption{}),
)
}
// Sync implements controllerlib.Syncer.Sync().
func (c *controller) Sync(ctx controllerlib.Context) error {
secret, err := c.secrets.Lister().Secrets(ctx.Key.Namespace).Get(ctx.Key.Name)
isNotFound := k8serrors.IsNotFound(err)
if !isNotFound && err != nil {
return fmt.Errorf("failed to list secret %s/%s: %w", ctx.Key.Namespace, ctx.Key.Name, err)
}
secretNeedsUpdate := isNotFound || !c.isValid(secret)
if !secretNeedsUpdate {
plog.Debug("secret is up to date", "secret", klog.KObj(secret))
return nil
}
newSecret, err := c.generateSecret(ctx.Key.Namespace)
if err != nil {
return fmt.Errorf("failed to generate secret: %w", err)
}
if isNotFound {
err = c.createSecret(ctx.Context, newSecret)
} else {
err = c.updateSecret(ctx.Context, newSecret, ctx.Key.Name)
}
if err != nil {
return fmt.Errorf("failed to create/update secret %s/%s: %w", ctx.Key.Namespace, ctx.Key.Name, err)
}
return nil
}
func (c *controller) isValid(secret *corev1.Secret) bool {
if secret.Type != symmetricKeySecretType {
return false
}
data, ok := secret.Data[symmetricKeySecretDataKey]
if !ok {
return false
}
if len(data) != symmetricKeySize {
return false
}
return true
}
func (c *controller) generateSecret(namespace string) (*corev1.Secret, error) {
symmetricKey, err := generateKey()
if err != nil {
return nil, err
}
return &corev1.Secret{
ObjectMeta: metav1.ObjectMeta{
GenerateName: c.secretNamePrefix,
Namespace: namespace,
},
Type: symmetricKeySecretType,
Data: map[string][]byte{
symmetricKeySecretDataKey: symmetricKey,
},
}, nil
}
func (c *controller) createSecret(ctx context.Context, newSecret *corev1.Secret) error {
_, err := c.client.CoreV1().Secrets(newSecret.Namespace).Create(ctx, newSecret, metav1.CreateOptions{})
return err
}
func (c *controller) updateSecret(ctx context.Context, newSecret *corev1.Secret, secretName string) error {
secrets := c.client.CoreV1().Secrets(newSecret.Namespace)
return retry.RetryOnConflict(retry.DefaultBackoff, func() error {
currentSecret, err := secrets.Get(ctx, secretName, metav1.GetOptions{})
isNotFound := k8serrors.IsNotFound(err)
if !isNotFound && err != nil {
return fmt.Errorf("failed to get secret: %w", err)
}
if isNotFound {
if err := c.createSecret(ctx, newSecret); err != nil {
return fmt.Errorf("failed to create secret: %w", err)
}
return nil
}
if c.isValid(currentSecret) {
return nil
}
currentSecret.Type = newSecret.Type
currentSecret.Data = newSecret.Data
_, err = secrets.Update(ctx, currentSecret, metav1.UpdateOptions{})
return err
})
}
// isOwnee returns whether the provided obj is owned by this controller.
func isOwnee(obj metav1.Object) bool {
// TODO: how do we say we are owned by our Deployment?
return true
}

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@ -0,0 +1,294 @@
// Copyright 2020 the Pinniped contributors. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
package secretgenerator
import (
"context"
"errors"
"sync"
"testing"
"time"
"github.com/stretchr/testify/require"
corev1 "k8s.io/api/core/v1"
k8serrors "k8s.io/apimachinery/pkg/api/errors"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/apimachinery/pkg/runtime/schema"
kubeinformers "k8s.io/client-go/informers"
kubernetesfake "k8s.io/client-go/kubernetes/fake"
kubetesting "k8s.io/client-go/testing"
"go.pinniped.dev/internal/controllerlib"
)
func TestController(t *testing.T) {
const (
generatedSecretNamespace = "some-namespace"
generatedSecretNamePrefix = "some-name-"
generatedSecretName = "some-name-abc123"
)
var (
secretsGVR = schema.GroupVersionResource{
Group: corev1.SchemeGroupVersion.Group,
Version: corev1.SchemeGroupVersion.Version,
Resource: "secrets",
}
generatedSymmetricKey = []byte("some-neato-32-byte-generated-key")
generatedSecret = &corev1.Secret{
ObjectMeta: metav1.ObjectMeta{
GenerateName: generatedSecretNamePrefix,
Namespace: generatedSecretNamespace,
},
Type: "secrets.pinniped.dev/symmetric",
Data: map[string][]byte{
"key": generatedSymmetricKey,
},
}
)
generatedSecretWithName := generatedSecret.DeepCopy()
generatedSecretWithName.Name = generatedSecretName
once := sync.Once{}
tests := []struct {
name string
storedSecret func(**corev1.Secret)
generateKey func() ([]byte, error)
apiClient func(*testing.T, *kubernetesfake.Clientset)
wantError string
wantActions []kubetesting.Action
}{
{
name: "when the secrets does not exist, it gets generated",
storedSecret: func(secret **corev1.Secret) {
*secret = nil
},
wantActions: []kubetesting.Action{
kubetesting.NewCreateAction(secretsGVR, generatedSecretNamespace, generatedSecret),
},
},
{
name: "when a valid secret exists, nothing happens",
},
{
name: "secret gets updated when the type is wrong",
storedSecret: func(secret **corev1.Secret) {
(*secret).Type = "wrong"
},
wantActions: []kubetesting.Action{
kubetesting.NewGetAction(secretsGVR, generatedSecretNamespace, generatedSecretName),
kubetesting.NewUpdateAction(secretsGVR, generatedSecretNamespace, generatedSecretWithName),
},
},
{
name: "secret gets updated when the key data does not exist",
storedSecret: func(secret **corev1.Secret) {
delete((*secret).Data, "key")
},
wantActions: []kubetesting.Action{
kubetesting.NewGetAction(secretsGVR, generatedSecretNamespace, generatedSecretName),
kubetesting.NewUpdateAction(secretsGVR, generatedSecretNamespace, generatedSecretWithName),
},
},
{
name: "secret gets updated when the key data is too short",
storedSecret: func(secret **corev1.Secret) {
(*secret).Data["key"] = []byte("too short")
},
wantActions: []kubetesting.Action{
kubetesting.NewGetAction(secretsGVR, generatedSecretNamespace, generatedSecretName),
kubetesting.NewUpdateAction(secretsGVR, generatedSecretNamespace, generatedSecretWithName),
},
},
{
name: "an error is returned when creating fails",
storedSecret: func(secret **corev1.Secret) {
*secret = nil
},
apiClient: func(t *testing.T, client *kubernetesfake.Clientset) {
client.PrependReactor("create", "secrets", func(action kubetesting.Action) (bool, runtime.Object, error) {
return true, nil, errors.New("some create error")
})
},
wantActions: []kubetesting.Action{
kubetesting.NewCreateAction(secretsGVR, generatedSecretNamespace, generatedSecret),
},
wantError: "failed to create/update secret some-namespace/some-name-abc123: some create error",
},
{
name: "an error is returned when updating fails",
storedSecret: func(secret **corev1.Secret) {
(*secret).Data["key"] = []byte("too short") // force updating
},
apiClient: func(t *testing.T, client *kubernetesfake.Clientset) {
client.PrependReactor("update", "secrets", func(action kubetesting.Action) (bool, runtime.Object, error) {
return true, nil, errors.New("some update error")
})
},
wantActions: []kubetesting.Action{
kubetesting.NewGetAction(secretsGVR, generatedSecretNamespace, generatedSecretName),
kubetesting.NewUpdateAction(secretsGVR, generatedSecretNamespace, generatedSecretWithName),
},
wantError: "failed to create/update secret some-namespace/some-name-abc123: some update error",
},
{
name: "an error is returned when getting fails",
storedSecret: func(secret **corev1.Secret) {
(*secret).Data["key"] = []byte("too short") // force updating
},
apiClient: func(t *testing.T, client *kubernetesfake.Clientset) {
client.PrependReactor("get", "secrets", func(action kubetesting.Action) (bool, runtime.Object, error) {
return true, nil, errors.New("some get error")
})
},
wantActions: []kubetesting.Action{
kubetesting.NewGetAction(secretsGVR, generatedSecretNamespace, generatedSecretName),
},
wantError: "failed to create/update secret some-namespace/some-name-abc123: failed to get secret: some get error",
},
{
name: "the update is retried when it fails due to a conflict",
storedSecret: func(secret **corev1.Secret) {
(*secret).Data["key"] = []byte("too short") // force updating
},
apiClient: func(t *testing.T, client *kubernetesfake.Clientset) {
client.PrependReactor("update", "secrets", func(action kubetesting.Action) (bool, runtime.Object, error) {
var err error
once.Do(func() {
err = k8serrors.NewConflict(secretsGVR.GroupResource(), generatedSecretName, errors.New("some error"))
})
return true, nil, err
})
},
wantActions: []kubetesting.Action{
kubetesting.NewGetAction(secretsGVR, generatedSecretNamespace, generatedSecretName),
kubetesting.NewUpdateAction(secretsGVR, generatedSecretNamespace, generatedSecretWithName),
kubetesting.NewGetAction(secretsGVR, generatedSecretNamespace, generatedSecretName),
kubetesting.NewUpdateAction(secretsGVR, generatedSecretNamespace, generatedSecretWithName),
},
},
{
name: "upon updating we discover that a valid secret exists",
storedSecret: func(secret **corev1.Secret) {
(*secret).Data["key"] = []byte("too short") // force updating
},
apiClient: func(t *testing.T, client *kubernetesfake.Clientset) {
client.PrependReactor("get", "secrets", func(action kubetesting.Action) (bool, runtime.Object, error) {
return true, generatedSecretWithName, nil
})
},
wantActions: []kubetesting.Action{
kubetesting.NewGetAction(secretsGVR, generatedSecretNamespace, generatedSecretName),
},
},
{
name: "upon updating we discover that the secret has been deleted",
storedSecret: func(secret **corev1.Secret) {
(*secret).Data["key"] = []byte("too short") // force updating
},
apiClient: func(t *testing.T, client *kubernetesfake.Clientset) {
client.PrependReactor("get", "secrets", func(action kubetesting.Action) (bool, runtime.Object, error) {
return true, nil, k8serrors.NewNotFound(secretsGVR.GroupResource(), generatedSecretName)
})
client.PrependReactor("create", "secrets", func(action kubetesting.Action) (bool, runtime.Object, error) {
return true, nil, nil
})
},
wantActions: []kubetesting.Action{
kubetesting.NewGetAction(secretsGVR, generatedSecretNamespace, generatedSecretName),
kubetesting.NewCreateAction(secretsGVR, generatedSecretNamespace, generatedSecret),
},
},
{
name: "upon updating we discover that the secret has been deleted and our create fails",
storedSecret: func(secret **corev1.Secret) {
(*secret).Data["key"] = []byte("too short") // force updating
},
apiClient: func(t *testing.T, client *kubernetesfake.Clientset) {
client.PrependReactor("get", "secrets", func(action kubetesting.Action) (bool, runtime.Object, error) {
return true, nil, k8serrors.NewNotFound(secretsGVR.GroupResource(), generatedSecretName)
})
client.PrependReactor("create", "secrets", func(action kubetesting.Action) (bool, runtime.Object, error) {
return true, nil, errors.New("some create error")
})
},
wantActions: []kubetesting.Action{
kubetesting.NewGetAction(secretsGVR, generatedSecretNamespace, generatedSecretName),
kubetesting.NewCreateAction(secretsGVR, generatedSecretNamespace, generatedSecret),
},
wantError: "failed to create/update secret some-namespace/some-name-abc123: failed to create secret: some create error",
},
{
name: "when generating the secret fails, we return an error",
generateKey: func() ([]byte, error) {
return nil, errors.New("some generate error")
},
wantError: "failed to generate secret: some generate error",
},
}
for _, test := range tests {
test := test
t.Run(test.name, func(t *testing.T) {
// We cannot currently run this test in parallel since it uses the global generateKey function.
ctx, cancel := context.WithTimeout(context.Background(), time.Second*3)
defer cancel()
if test.generateKey != nil {
generateKey = test.generateKey
} else {
generateKey = func() ([]byte, error) {
return generatedSymmetricKey, nil
}
}
apiClient := kubernetesfake.NewSimpleClientset()
if test.apiClient != nil {
test.apiClient(t, apiClient)
}
informerClient := kubernetesfake.NewSimpleClientset()
storedSecret := generatedSecretWithName.DeepCopy()
if test.storedSecret != nil {
test.storedSecret(&storedSecret)
}
if storedSecret != nil {
require.NoError(t, apiClient.Tracker().Add(storedSecret))
require.NoError(t, informerClient.Tracker().Add(storedSecret))
}
informers := kubeinformers.NewSharedInformerFactory(informerClient, 0)
secrets := informers.Core().V1().Secrets()
c := New(generatedSecretNamePrefix, apiClient, secrets)
// Must start informers before calling TestRunSynchronously().
informers.Start(ctx.Done())
controllerlib.TestRunSynchronously(t, c)
err := controllerlib.TestSync(t, c, controllerlib.Context{
Context: ctx,
Key: controllerlib.Key{
Namespace: generatedSecretNamespace,
Name: generatedSecretName,
},
})
if test.wantError != "" {
require.EqualError(t, err, test.wantError)
} else {
require.NoError(t, err)
}
if test.wantActions == nil {
test.wantActions = []kubetesting.Action{}
}
require.Equal(t, test.wantActions, apiClient.Actions())
})
}
}