terraform/backend/remote-state/kubernetes/client.go

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package kubernetes
import (
"bytes"
"compress/gzip"
"crypto/md5"
"encoding/base64"
"encoding/json"
"errors"
"fmt"
"strings"
"github.com/hashicorp/terraform/states/remote"
"github.com/hashicorp/terraform/states/statemgr"
k8serrors "k8s.io/apimachinery/pkg/api/errors"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
"k8s.io/apimachinery/pkg/util/validation"
"k8s.io/client-go/dynamic"
_ "k8s.io/client-go/plugin/pkg/client/auth" // Import to initialize client auth plugins.
"k8s.io/utils/pointer"
coordinationv1 "k8s.io/api/coordination/v1"
coordinationclientv1 "k8s.io/client-go/kubernetes/typed/coordination/v1"
)
const (
tfstateKey = "tfstate"
tfstateSecretSuffixKey = "tfstateSecretSuffix"
tfstateWorkspaceKey = "tfstateWorkspace"
tfstateLockInfoAnnotation = "app.terraform.io/lock-info"
managedByKey = "app.kubernetes.io/managed-by"
)
type RemoteClient struct {
kubernetesSecretClient dynamic.ResourceInterface
kubernetesLeaseClient coordinationclientv1.LeaseInterface
namespace string
labels map[string]string
nameSuffix string
workspace string
}
func (c *RemoteClient) Get() (payload *remote.Payload, err error) {
secretName, err := c.createSecretName()
if err != nil {
return nil, err
}
secret, err := c.kubernetesSecretClient.Get(secretName, metav1.GetOptions{})
if err != nil {
if k8serrors.IsNotFound(err) {
return nil, nil
}
return nil, err
}
secretData := getSecretData(secret)
stateRaw, ok := secretData[tfstateKey]
if !ok {
// The secret exists but there is no state in it
return nil, nil
}
stateRawString := stateRaw.(string)
state, err := uncompressState(stateRawString)
if err != nil {
return nil, err
}
md5 := md5.Sum(state)
p := &remote.Payload{
Data: state,
MD5: md5[:],
}
return p, nil
}
func (c *RemoteClient) Put(data []byte) error {
secretName, err := c.createSecretName()
if err != nil {
return err
}
payload, err := compressState(data)
if err != nil {
return err
}
secret, err := c.getSecret(secretName)
if err != nil {
if !k8serrors.IsNotFound(err) {
return err
}
secret = &unstructured.Unstructured{
Object: map[string]interface{}{
"metadata": metav1.ObjectMeta{
Name: secretName,
Namespace: c.namespace,
Labels: c.getLabels(),
Annotations: map[string]string{"encoding": "gzip"},
},
},
}
secret, err = c.kubernetesSecretClient.Create(secret, metav1.CreateOptions{})
if err != nil {
return err
}
}
setState(secret, payload)
_, err = c.kubernetesSecretClient.Update(secret, metav1.UpdateOptions{})
return err
}
// Delete the state secret
func (c *RemoteClient) Delete() error {
secretName, err := c.createSecretName()
if err != nil {
return err
}
err = c.deleteSecret(secretName)
if err != nil {
if !k8serrors.IsNotFound(err) {
return err
}
}
leaseName, err := c.createLeaseName()
if err != nil {
return err
}
err = c.deleteLease(leaseName)
if err != nil {
if !k8serrors.IsNotFound(err) {
return err
}
}
return nil
}
func (c *RemoteClient) Lock(info *statemgr.LockInfo) (string, error) {
leaseName, err := c.createLeaseName()
if err != nil {
return "", err
}
lease, err := c.getLease(leaseName)
if err != nil {
if !k8serrors.IsNotFound(err) {
return "", err
}
labels := c.getLabels()
lease = &coordinationv1.Lease{
ObjectMeta: metav1.ObjectMeta{
Name: leaseName,
Labels: labels,
Annotations: map[string]string{
tfstateLockInfoAnnotation: string(info.Marshal()),
},
},
Spec: coordinationv1.LeaseSpec{
HolderIdentity: pointer.StringPtr(info.ID),
},
}
_, err = c.kubernetesLeaseClient.Create(lease)
if err != nil {
return "", err
} else {
return info.ID, nil
}
}
if lease.Spec.HolderIdentity != nil {
if *lease.Spec.HolderIdentity == info.ID {
return info.ID, nil
}
currentLockInfo, err := c.getLockInfo(lease)
if err != nil {
return "", err
}
lockErr := &statemgr.LockError{
Info: currentLockInfo,
Err: errors.New("the state is already locked by another terraform client"),
}
return "", lockErr
}
lease.Spec.HolderIdentity = pointer.StringPtr(info.ID)
setLockInfo(lease, info.Marshal())
_, err = c.kubernetesLeaseClient.Update(lease)
if err != nil {
return "", err
}
return info.ID, err
}
func (c *RemoteClient) Unlock(id string) error {
leaseName, err := c.createLeaseName()
if err != nil {
return err
}
lease, err := c.getLease(leaseName)
if err != nil {
return err
}
if lease.Spec.HolderIdentity == nil {
2020-06-06 00:10:24 +02:00
return fmt.Errorf("state is already unlocked")
}
lockInfo, err := c.getLockInfo(lease)
if err != nil {
return err
}
lockErr := &statemgr.LockError{Info: lockInfo}
if *lease.Spec.HolderIdentity != id {
lockErr.Err = fmt.Errorf("lock id %q does not match existing lock", id)
return lockErr
}
lease.Spec.HolderIdentity = nil
removeLockInfo(lease)
_, err = c.kubernetesLeaseClient.Update(lease)
if err != nil {
lockErr.Err = err
return lockErr
}
return nil
}
func (c *RemoteClient) getLockInfo(lease *coordinationv1.Lease) (*statemgr.LockInfo, error) {
lockData, ok := getLockInfo(lease)
if len(lockData) == 0 || !ok {
return nil, nil
}
lockInfo := &statemgr.LockInfo{}
err := json.Unmarshal(lockData, lockInfo)
if err != nil {
return nil, err
}
return lockInfo, nil
}
func (c *RemoteClient) getLabels() map[string]string {
l := map[string]string{
tfstateKey: "true",
tfstateSecretSuffixKey: c.nameSuffix,
tfstateWorkspaceKey: c.workspace,
managedByKey: "terraform",
}
if len(c.labels) != 0 {
for k, v := range c.labels {
l[k] = v
}
}
return l
}
func (c *RemoteClient) getSecret(name string) (*unstructured.Unstructured, error) {
return c.kubernetesSecretClient.Get(name, metav1.GetOptions{})
}
func (c *RemoteClient) getLease(name string) (*coordinationv1.Lease, error) {
return c.kubernetesLeaseClient.Get(name, metav1.GetOptions{})
}
func (c *RemoteClient) deleteSecret(name string) error {
secret, err := c.getSecret(name)
if err != nil {
return err
}
labels := secret.GetLabels()
v, ok := labels[tfstateKey]
if !ok || v != "true" {
return fmt.Errorf("Secret does does not have %q label", tfstateKey)
}
delProp := metav1.DeletePropagationBackground
delOps := &metav1.DeleteOptions{PropagationPolicy: &delProp}
return c.kubernetesSecretClient.Delete(name, delOps)
}
func (c *RemoteClient) deleteLease(name string) error {
secret, err := c.getLease(name)
if err != nil {
return err
}
labels := secret.GetLabels()
v, ok := labels[tfstateKey]
if !ok || v != "true" {
return fmt.Errorf("Lease does does not have %q label", tfstateKey)
}
delProp := metav1.DeletePropagationBackground
delOps := &metav1.DeleteOptions{PropagationPolicy: &delProp}
return c.kubernetesLeaseClient.Delete(name, delOps)
}
func (c *RemoteClient) createSecretName() (string, error) {
secretName := strings.Join([]string{tfstateKey, c.workspace, c.nameSuffix}, "-")
errs := validation.IsDNS1123Subdomain(secretName)
if len(errs) > 0 {
k8sInfo := `
This is a requirement for Kubernetes secret names.
The workspace name and key must adhere to Kubernetes naming conventions.`
msg := fmt.Sprintf("the secret name %v is invalid, ", secretName)
return "", errors.New(msg + strings.Join(errs, ",") + k8sInfo)
}
return secretName, nil
}
func (c *RemoteClient) createLeaseName() (string, error) {
n, err := c.createSecretName()
if err != nil {
return "", err
}
return "lock-" + n, nil
}
func compressState(data []byte) ([]byte, error) {
b := new(bytes.Buffer)
gz := gzip.NewWriter(b)
if _, err := gz.Write(data); err != nil {
return nil, err
}
if err := gz.Close(); err != nil {
return nil, err
}
return b.Bytes(), nil
}
func uncompressState(data string) ([]byte, error) {
decode, err := base64.StdEncoding.DecodeString(data)
if err != nil {
return nil, err
}
b := new(bytes.Buffer)
gz, err := gzip.NewReader(bytes.NewReader(decode))
if err != nil {
return nil, err
}
b.ReadFrom(gz)
if err := gz.Close(); err != nil {
return nil, err
}
return b.Bytes(), nil
}
func getSecretData(secret *unstructured.Unstructured) map[string]interface{} {
if m, ok := secret.Object["data"].(map[string]interface{}); ok {
return m
}
return map[string]interface{}{}
}
func getLockInfo(lease *coordinationv1.Lease) ([]byte, bool) {
info, ok := lease.ObjectMeta.GetAnnotations()[tfstateLockInfoAnnotation]
if !ok {
return nil, false
}
return []byte(info), true
}
func setLockInfo(lease *coordinationv1.Lease, l []byte) {
annotations := lease.ObjectMeta.GetAnnotations()
if annotations != nil {
annotations[tfstateLockInfoAnnotation] = string(l)
} else {
annotations = map[string]string{
tfstateLockInfoAnnotation: string(l),
}
}
lease.ObjectMeta.SetAnnotations(annotations)
}
func removeLockInfo(lease *coordinationv1.Lease) {
annotations := lease.ObjectMeta.GetAnnotations()
delete(annotations, tfstateLockInfoAnnotation)
lease.ObjectMeta.SetAnnotations(annotations)
}
func setState(secret *unstructured.Unstructured, t []byte) {
secretData := getSecretData(secret)
secretData[tfstateKey] = t
secret.Object["data"] = secretData
}