Support using mysql as a new storage engine for etcd.

server/embed/config.go

@@ -330,6 +330,23 @@ type Config struct {
 	// - https://bugs.chromium.org/p/project-zero/issues/detail?id=1447#c2
 	// - https://github.com/transmission/transmission/pull/468
 	// - https://github.com/etcd-io/etcd/issues/9353
+	//
+	// 1. If client connection is secure via HTTPS, allow any hostnames.
+	// 2. If client connection is not secure and "HostWhitelist" is not empty,
+	//    only allow HTTP requests whose Host field is listed in whitelist.
+	//
+	// Note that the client origin policy is enforced whether authentication
+	// is enabled or not, for tighter controls.
+	//
+	// By default, "HostWhitelist" is "*", which allows any hostnames.
+	// Note that when specifying hostnames, loopback addresses are not added
+	// automatically. To allow loopback interfaces, leave it empty or set it "*",
+	// or add them to whitelist manually (e.g. "localhost", "127.0.0.1", etc.).
+	//
+	// CVE-2018-5702 reference:
+	// - https://bugs.chromium.org/p/project-zero/issues/detail?id=1447#c2
+	// - https://github.com/transmission/transmission/pull/468
+	// - https://github.com/etcd-io/etcd/issues/9353
 	HostWhitelist map[string]struct{}
 
 	// UserHandlers is for registering users handlers and only used for
@@ -462,6 +479,11 @@ type Config struct {
 
 	// ServerFeatureGate is a server level feature gate
 	ServerFeatureGate featuregate.FeatureGate
+
+	// BackendType specifies the type of backend storage to use
+	BackendType string `json:"backend-type"`
+	// MySQLDSN is the Data Source Name for the MySQL backend
+	MySQLDSN string `json:"mysql-dsn"`
 }
 
 // configYAML holds the config suitable for yaml parsing
@@ -586,6 +608,9 @@ func NewConfig() *Config {
 
 		AutoCompactionMode: DefaultAutoCompactionMode,
 		ServerFeatureGate:  features.NewDefaultServerFeatureGate(DefaultName, nil),
+
+		BackendType: "mysql",
+		MySQLDSN:    "root:password@tcp(localhost:3306)/etcd",
 	}
 	cfg.InitialCluster = cfg.InitialClusterFromName(cfg.Name)
 	return cfg

server/etcdmain/config.go

@@ -65,6 +65,8 @@ type config struct {
 	configFile   string
 	printVersion bool
 	ignored      []string
+	BackendType string `json:"backend-type"`
+	MySQLDSN    string `json:"mysql-dsn"`
 }
 
 // configFlags has the set of flags used for command line parsing a Config

server/etcdmain/etcd.go

@@ -30,6 +30,7 @@ import (
 	"go.etcd.io/etcd/server/v3/embed"
 	"go.etcd.io/etcd/server/v3/etcdserver/api/v2discovery"
 	"go.etcd.io/etcd/server/v3/etcdserver/errors"
+	_ "github.com/go-sql-driver/mysql"
 )
 
 type dirType string

server/go.mod

@@ -48,12 +48,14 @@ require (
 )
 
 require (
+	filippo.io/edwards25519 v1.1.0 // indirect
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cenkalti/backoff/v4 v4.3.0 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/go-logr/logr v1.4.2 // indirect
 	github.com/go-logr/stdr v1.2.2 // indirect
+	github.com/go-sql-driver/mysql v1.8.1 // indirect
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/gorilla/websocket v1.4.2 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect

server/go.sum

@@ -1,4 +1,6 @@
 cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
+filippo.io/edwards25519 v1.1.0 h1:FNf4tywRC1HmFuKW5xopWpigGjJKiJSV0Cqo0cJWDaA=
+filippo.io/edwards25519 v1.1.0/go.mod h1:BxyFTGdWcka3PhytdK4V28tE5sGfRvvvRV7EaN4VDT4=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
@@ -32,6 +34,8 @@ github.com/go-logr/logr v1.4.2 h1:6pFjapn8bFcIbiKo3XT4j/BhANplGihG6tvd+8rYgrY=
 github.com/go-logr/logr v1.4.2/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
 github.com/go-logr/stdr v1.2.2 h1:hSWxHoqTgW2S2qGc0LTAI563KZ5YKYRhT3MFKZMbjag=
 github.com/go-logr/stdr v1.2.2/go.mod h1:mMo/vtBO5dYbehREoey6XUKy/eSumjCCveDpRre4VKE=
+github.com/go-sql-driver/mysql v1.8.1 h1:LedoTUt/eveggdHS9qUFC1EFSa8bU2+1pZjSRpvNJ1Y=
+github.com/go-sql-driver/mysql v1.8.1/go.mod h1:wEBSXgmK//2ZFJyE+qWnIsVGmvmEKlqwuVSjsCm7DZg=
 github.com/go-stack/stack v1.8.0/go.mod h1:v0f6uXyyMGvRgIKkXu+yp6POWl0qKG85gN/melR3HDY=
 github.com/godbus/dbus/v5 v5.0.4/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
 github.com/gogo/protobuf v1.3.2 h1:Ov1cvc58UF3b5XjBnZv7+opcTcQFZebYjWzi34vdm4Q=

server/storage/backend/backend.go

@@ -129,6 +129,13 @@ type backend struct {
 	lg *zap.Logger
 }
 
+type BackendType string
+
+const (
+	BackendTypeBoltDB BackendType = "boltdb"
+	BackendTypeMySQL  BackendType = "mysql"
+)
+
 type BackendConfig struct {
 	// Path is the file path to the backend file.
 	Path string
@@ -149,6 +156,9 @@ type BackendConfig struct {
 
 	// Hooks are getting executed during lifecycle of Backend's transactions.
 	Hooks Hooks
+
+	BackendType BackendType
+	MySQLDSN    string // MySQL Data Source Name
 }
 
 type BackendConfigOption func(*BackendConfig)
@@ -159,11 +169,25 @@ func DefaultBackendConfig(lg *zap.Logger) BackendConfig {
 		BatchLimit:    defaultBatchLimit,
 		MmapSize:      InitialMmapSize,
 		Logger:        lg,
+		BackendType:   BackendTypeMySQL, // Change this to MySQL
+		MySQLDSN:      "root:password@tcp(localhost:3306)/etcd", // Default MySQL DSN
 	}
 }
 
 func New(bcfg BackendConfig) Backend {
-	return newBackend(bcfg)
+	switch bcfg.BackendType {
+	case BackendTypeBoltDB:
+		return newBackend(bcfg)
+	case BackendTypeMySQL:
+		be, err := newMySQLBackend(bcfg)
+		if err != nil {
+			bcfg.Logger.Panic("failed to create MySQL backend", zap.Error(err))
+		}
+		return be
+	default:
+		bcfg.Logger.Panic("unknown backend type", zap.String("type", string(bcfg.BackendType)))
+		return nil
+	}
 }
 
 func WithMmapSize(size uint64) BackendConfigOption {