/
etcd.go
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/
etcd.go
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// Licensed to Apache Software Foundation (ASF) under one or more contributor
// license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright
// ownership. Apache Software Foundation (ASF) licenses this file to you 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 schema
import (
"context"
"fmt"
"path"
"sync"
"time"
"github.com/pkg/errors"
clientv3 "go.etcd.io/etcd/client/v3"
"go.uber.org/zap"
"google.golang.org/protobuf/proto"
commonv1 "github.com/apache/skywalking-banyandb/api/proto/banyandb/common/v1"
"github.com/apache/skywalking-banyandb/pkg/logger"
"github.com/apache/skywalking-banyandb/pkg/run"
)
var (
_ Stream = (*etcdSchemaRegistry)(nil)
_ IndexRuleBinding = (*etcdSchemaRegistry)(nil)
_ IndexRule = (*etcdSchemaRegistry)(nil)
_ Measure = (*etcdSchemaRegistry)(nil)
_ Group = (*etcdSchemaRegistry)(nil)
_ Property = (*etcdSchemaRegistry)(nil)
errUnexpectedNumberOfEntities = errors.New("unexpected number of entities")
errConcurrentModification = errors.New("concurrent modification of entities")
)
// HasMetadata allows getting Metadata.
type HasMetadata interface {
GetMetadata() *commonv1.Metadata
proto.Message
}
// RegistryOption is the option to create Registry.
type RegistryOption func(*etcdSchemaRegistryConfig)
// Namespace sets the namespace of the registry.
func Namespace(namespace string) RegistryOption {
return func(config *etcdSchemaRegistryConfig) {
config.namespace = namespace
}
}
// ConfigureServerEndpoints sets a list of the server urls.
func ConfigureServerEndpoints(url []string) RegistryOption {
return func(config *etcdSchemaRegistryConfig) {
config.serverEndpoints = url
}
}
type etcdSchemaRegistry struct {
namespace string
client *clientv3.Client
closer *run.Closer
l *logger.Logger
watchers []*watcher
mux sync.RWMutex
}
type etcdSchemaRegistryConfig struct {
namespace string
serverEndpoints []string
}
func (e *etcdSchemaRegistry) RegisterHandler(name string, kind Kind, handler EventHandler) {
// Validate kind
if kind&KindMask != kind {
panic(fmt.Sprintf("invalid kind %d", kind))
}
e.mux.Lock()
defer e.mux.Unlock()
for i := 0; i < KindSize; i++ {
ki := Kind(1 << i)
if kind&ki > 0 {
e.l.Info().Str("name", name).Stringer("kind", ki).Msg("registering watcher")
w := e.newWatcher(name, ki, handler)
e.watchers = append(e.watchers, w)
}
}
}
func (e *etcdSchemaRegistry) Close() error {
e.closer.Done()
e.closer.CloseThenWait()
for i, w := range e.watchers {
_ = w.Close()
e.watchers[i] = nil
}
return e.client.Close()
}
// NewEtcdSchemaRegistry returns a Registry powered by Etcd.
func NewEtcdSchemaRegistry(options ...RegistryOption) (Registry, error) {
registryConfig := &etcdSchemaRegistryConfig{}
for _, opt := range options {
opt(registryConfig)
}
if registryConfig.serverEndpoints == nil {
return nil, errors.New("server address is not set")
}
log := logger.GetLogger("etcd")
zapCfg := log.ToZapConfig()
var l *zap.Logger
var err error
if l, err = zapCfg.Build(); err != nil {
return nil, err
}
config := clientv3.Config{
Endpoints: registryConfig.serverEndpoints,
DialTimeout: 5 * time.Second,
DialKeepAliveTime: 30 * time.Second,
DialKeepAliveTimeout: 10 * time.Second,
AutoSyncInterval: 5 * time.Minute,
Logger: l,
}
client, err := clientv3.New(config)
if err != nil {
return nil, err
}
reg := &etcdSchemaRegistry{
namespace: registryConfig.namespace,
client: client,
closer: run.NewCloser(1),
l: log,
}
return reg, nil
}
func (e *etcdSchemaRegistry) prependNamespace(key string) string {
if e.namespace == "" {
return key
}
return path.Join("/", e.namespace, key)
}
func (e *etcdSchemaRegistry) get(ctx context.Context, key string, message proto.Message) error {
if !e.closer.AddRunning() {
return ErrClosed
}
defer e.closer.Done()
key = e.prependNamespace(key)
resp, err := e.client.Get(ctx, key)
if err != nil {
return err
}
if resp.Count == 0 {
return ErrGRPCResourceNotFound
}
if resp.Count > 1 {
return errUnexpectedNumberOfEntities
}
if err = proto.Unmarshal(resp.Kvs[0].Value, message); err != nil {
return err
}
if messageWithMetadata, ok := message.(HasMetadata); ok {
// Assign readonly fields
messageWithMetadata.GetMetadata().CreateRevision = resp.Kvs[0].CreateRevision
messageWithMetadata.GetMetadata().ModRevision = resp.Kvs[0].ModRevision
}
return nil
}
// update will first ensure the existence of the entity with the metadata,
// and overwrite the existing value if so.
// Otherwise, it will return ErrGRPCResourceNotFound.
func (e *etcdSchemaRegistry) update(ctx context.Context, metadata Metadata) (int64, error) {
if !e.closer.AddRunning() {
return 0, ErrClosed
}
defer e.closer.Done()
key, err := metadata.key()
if err != nil {
return 0, err
}
key = e.prependNamespace(key)
getResp, err := e.client.Get(ctx, key)
if err != nil {
return 0, err
}
if getResp.Count > 1 {
return 0, errUnexpectedNumberOfEntities
}
val, err := proto.Marshal(metadata.Spec.(proto.Message))
if err != nil {
return 0, err
}
replace := getResp.Count > 0
if !replace {
return 0, ErrGRPCResourceNotFound
}
existingVal, innerErr := metadata.Kind.Unmarshal(getResp.Kvs[0])
if innerErr != nil {
return 0, innerErr
}
// directly return if we have the same entity
if metadata.equal(existingVal) {
return 0, nil
}
modRevision := metadata.ModRevision
if modRevision == 0 {
modRevision = getResp.Kvs[0].ModRevision
}
txnResp, txnErr := e.client.Txn(ctx).
If(clientv3.Compare(clientv3.ModRevision(key), "=", modRevision)).
Then(clientv3.OpPut(key, string(val))).
Commit()
if txnErr != nil {
return 0, txnErr
}
if !txnResp.Succeeded {
return 0, errConcurrentModification
}
return txnResp.Responses[0].GetResponsePut().Header.Revision, nil
}
// create will first check existence of the entity with the metadata,
// and put the value if it does not exist.
// Otherwise, it will return ErrGRPCAlreadyExists.
func (e *etcdSchemaRegistry) create(ctx context.Context, metadata Metadata) (int64, error) {
if !e.closer.AddRunning() {
return 0, ErrClosed
}
defer e.closer.Done()
key, err := metadata.key()
if err != nil {
return 0, err
}
key = e.prependNamespace(key)
getResp, err := e.client.Get(ctx, key)
if err != nil {
return 0, err
}
if getResp.Count > 1 {
return 0, errUnexpectedNumberOfEntities
}
val, err := proto.Marshal(metadata.Spec.(proto.Message))
if err != nil {
return 0, err
}
replace := getResp.Count > 0
if replace {
return 0, errGRPCAlreadyExists
}
putResp, err := e.client.Put(ctx, key, string(val))
if err != nil {
return 0, err
}
return putResp.Header.Revision, nil
}
func (e *etcdSchemaRegistry) listWithPrefix(ctx context.Context, prefix string, kind Kind) ([]proto.Message, error) {
if !e.closer.AddRunning() {
return nil, ErrClosed
}
defer e.closer.Done()
prefix = e.prependNamespace(prefix)
resp, err := e.client.Get(ctx, prefix, clientv3.WithPrefix())
if err != nil {
return nil, err
}
entities := make([]proto.Message, resp.Count)
for i := int64(0); i < resp.Count; i++ {
md, err := kind.Unmarshal(resp.Kvs[i])
if err != nil {
return nil, err
}
entities[i] = md.Spec.(proto.Message)
}
return entities, nil
}
func (e *etcdSchemaRegistry) delete(ctx context.Context, metadata Metadata) (bool, error) {
if !e.closer.AddRunning() {
return false, ErrClosed
}
defer e.closer.Done()
key, err := metadata.key()
if err != nil {
return false, err
}
key = e.prependNamespace(key)
resp, err := e.client.Delete(ctx, key, clientv3.WithPrevKV())
if err != nil {
return false, err
}
if resp.Deleted == 1 {
return true, nil
}
return false, nil
}
func (e *etcdSchemaRegistry) register(ctx context.Context, metadata Metadata, forced bool) error {
if !e.closer.AddRunning() {
return ErrClosed
}
defer e.closer.Done()
key, err := metadata.key()
if err != nil {
return err
}
key = e.prependNamespace(key)
val, err := proto.Marshal(metadata.Spec.(proto.Message))
if err != nil {
return err
}
// Create a lease with a short TTL
lease, err := e.client.Grant(ctx, 5) // 5 seconds
if err != nil {
return err
}
if forced {
if _, err = e.client.Put(ctx, key, string(val), clientv3.WithLease(lease.ID)); err != nil {
return err
}
} else {
var ops []clientv3.Cmp
ops = append(ops, clientv3.Compare(clientv3.CreateRevision(key), "=", 0))
txn := e.client.Txn(ctx).If(ops...)
txn = txn.Then(clientv3.OpPut(key, string(val), clientv3.WithLease(lease.ID)))
txn = txn.Else(clientv3.OpGet(key))
response, errCommit := txn.Commit()
if errCommit != nil {
return errCommit
}
if !response.Succeeded {
return errGRPCAlreadyExists
}
}
// Keep the lease alive
// nolint:contextcheck
keepAliveChan, err := e.client.KeepAlive(context.Background(), lease.ID)
if err != nil {
return err
}
go func() {
if !e.closer.AddRunning() {
return
}
defer func() {
_, _ = e.client.Lease.Revoke(context.Background(), lease.ID)
e.closer.Done()
}()
for {
select {
case <-e.closer.CloseNotify():
return
case keepAliveResp := <-keepAliveChan:
if keepAliveResp == nil {
// The channel has been closed
return
}
}
}
}()
return nil
}
func (e *etcdSchemaRegistry) newWatcher(name string, kind Kind, handler EventHandler) *watcher {
return newWatcher(e.client, watcherConfig{
key: e.prependNamespace(kind.key()),
kind: kind,
handler: handler,
}, e.l.Named(fmt.Sprintf("watcher-%s[%s]", name, kind.String())))
}
func listPrefixesForEntity(group, entityPrefix string) string {
return path.Join(entityPrefix, group)
}
func formatKey(entityPrefix string, metadata *commonv1.Metadata) string {
return path.Join(
listPrefixesForEntity(metadata.GetGroup(), entityPrefix),
metadata.GetName())
}