backend: update db in the handshake (#102)

.golangci.yaml

@@ -18,9 +18,6 @@ issues:
       linters:
         - gosec
       text: "G402:"
-    - linters:
-        - unused
-      source: "updateAuthInfoFromSessionStates"
 
 linters:
   enable:

pkg/proxy/backend/backend_conn_mgr.go

@@ -32,6 +32,7 @@ import (
 	"github.com/pingcap/TiProxy/pkg/manager/router"
 	pnet "github.com/pingcap/TiProxy/pkg/proxy/net"
 	"github.com/pingcap/tidb/parser/mysql"
+	"github.com/siddontang/go/hack"
 	"go.uber.org/zap"
 )
 
@@ -265,6 +266,9 @@ func (mgr *BackendConnManager) tryRedirect(ctx context.Context) {
 	if sessionStates, sessionToken, rs.err = mgr.querySessionStates(); rs.err != nil {
 		return
 	}
+	if rs.err = mgr.updateAuthInfoFromSessionStates(hack.Slice(sessionStates)); rs.err != nil {
+		return
+	}
 
 	newConn := NewBackendConnection(rs.to)
 	if rs.err = newConn.Connect(); rs.err != nil {

pkg/proxy/backend/backend_conn_mgr_test.go

@@ -484,9 +484,10 @@ func TestSpecialCmds(t *testing.T) {
 				return nil
 			},
 			backend: func(packetIO *pnet.PacketIO) error {
+				ts.mb.sessionStates = "{\"current-db\":\"session_db\"}"
 				require.NoError(t, ts.redirectSucceed4Backend(packetIO))
 				require.Equal(t, "another_user", ts.mb.username)
-				require.Equal(t, "another_db", ts.mb.db)
+				require.Equal(t, "session_db", ts.mb.db)
 				expectCap := pnet.Capability(ts.mp.authenticator.supportedServerCapabilities.Uint32() &^ (mysql.ClientMultiStatements | mysql.ClientPluginAuthLenencClientData))
 				gotCap := pnet.Capability(ts.mb.clientCapability &^ mysql.ClientPluginAuthLenencClientData)
 				require.Equal(t, expectCap, gotCap, "expected=%s,got=%s", expectCap, gotCap)

pkg/proxy/backend/mock_backend_test.go

@@ -24,33 +24,33 @@ import (
 )
 
 type backendConfig struct {
-	// for auth
-	tlsConfig   *tls.Config
-	authPlugin  string
-	salt        []byte
-	columns     int
-	loops       int
-	params      int
-	rows        int
-	respondType respondType // for cmd
-	stmtNum     int
-	capability  uint32
-	status      uint16
-	authSucceed bool
-	switchAuth  bool
-	// for both auth and cmd
-	abnormalExit bool
+	tlsConfig     *tls.Config
+	authPlugin    string
+	sessionStates string
+	salt          []byte
+	columns       int
+	loops         int
+	params        int
+	rows          int
+	respondType   respondType
+	stmtNum       int
+	capability    uint32
+	status        uint16
+	authSucceed   bool
+	switchAuth    bool
+	abnormalExit  bool
 }
 
 func newBackendConfig() *backendConfig {
 	return &backendConfig{
-		capability:  defaultTestBackendCapability,
-		salt:        mockSalt,
-		authPlugin:  mysql.AuthCachingSha2Password,
-		switchAuth:  true,
-		authSucceed: true,
-		loops:       1,
-		stmtNum:     1,
+		capability:    defaultTestBackendCapability,
+		salt:          mockSalt,
+		authPlugin:    mysql.AuthCachingSha2Password,
+		switchAuth:    true,
+		authSucceed:   true,
+		loops:         1,
+		stmtNum:       1,
+		sessionStates: mockSessionStates,
 	}
 }
 
@@ -372,7 +372,7 @@ func (mb *mockBackend) respondSessionStates(packetIO *pnet.PacketIO) error {
 	names := []string{sessionStatesCol, sessionTokenCol}
 	values := [][]any{
 		{
-			mockSessionStates, mockCmdStr,
+			mb.sessionStates, mockCmdStr,
 		},
 	}
 	return mb.writeResultSet(packetIO, names, values)