session: add no register API for using TiDB as a library

config/config.go

@@ -141,6 +141,8 @@ type Config struct {
 	Experimental Experimental `toml:"experimental" json:"experimental"`
 	// EnableCollectExecutionInfo enables the TiDB to collect execution info.
 	EnableCollectExecutionInfo bool `toml:"enable-collect-execution-info" json:"enable-collect-execution-info"`
+	// NoRegister tells TiDB don't register itself to the dashboard.
+	NoRegister bool `toml:"no-register" json:"no-register"`
 }
 
 // UpdateTempStoragePath is to update the `TempStoragePath` if port/statusPort was changed

config/config.toml.example

@@ -109,6 +109,11 @@ max-server-connections = 0
 # Whether new collations are enabled, as indicated by its name, this configuration entry take effect ONLY when a TiDB cluster bootstraps for the first time.
 new_collations_enabled_on_first_bootstrap = false
 
+# Don't register information of this TiDB to etcd, so this instance of TiDB won't appear in the services like dashboard.
+# This option is useful when you want to embed TiDB into your service(i.e. use TiDB as a library).
+# *If you want to start a TiDB service, NEVER enable this.*
+no-register = false
+
 [log]
 # Log level: debug, info, warn, error, fatal.
 level = "info"

config/config_test.go

@@ -190,6 +190,7 @@ max-server-connections = 200
 mem-quota-query = 10000
 nested-loop-join-cache-capacity = 100
 max-index-length = 3080
+no-register = true
 [performance]
 txn-total-size-limit=2000
 [tikv-client]
@@ -247,6 +248,7 @@ engines = ["tiflash"]
 	c.Assert(conf.Experimental.AllowsExpressionIndex, IsTrue)
 	c.Assert(conf.IsolationRead.Engines, DeepEquals, []string{"tiflash"})
 	c.Assert(conf.MaxIndexLength, Equals, 3080)
+	c.Assert(conf.NoRegister, Equals, true)
 
 	_, err = f.WriteString(`
 [log.file]

domain/domain.go

@@ -749,8 +749,10 @@ func (do *Domain) Init(ddlLease time.Duration, sysFactory func(*Domain) (pools.R
 	do.wg.Add(1)
 	go do.infoSyncerKeeper()
 
-	do.wg.Add(1)
-	go do.topologySyncerKeeper()
+	if !config.GetGlobalConfig().NoRegister {
+		do.wg.Add(1)
+		go do.topologySyncerKeeper()
+	}
 
 	return nil
 }

domain/infosync/info.go

@@ -149,6 +149,9 @@ func (is *InfoSyncer) init(ctx context.Context) error {
 	if err != nil {
 		return err
 	}
+	if config.GetGlobalConfig().NoRegister {
+		return nil
+	}
 	return is.newTopologySessionAndStoreServerInfo(ctx, owner.NewSessionDefaultRetryCnt)
 }
 

session/tidb.go

@@ -23,6 +23,7 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/ngaut/pools"
 	"github.com/pingcap/errors"
 	"github.com/pingcap/parser"
 	"github.com/pingcap/parser/ast"
@@ -42,6 +43,12 @@ import (
 	"go.uber.org/zap"
 )
 
+type domainInitializer func(
+	dom *domain.Domain,
+	ddlLease time.Duration,
+	sysFactory func(*domain.Domain) (pools.Resource, error),
+) error
+
 type domainMap struct {
 	domains map[string]*domain.Domain
 	mu      sync.Mutex