MSSQL: By default let driver choose port (#32417)

* MSSQL: By default let driver choose port

Signed-off-by: Arve Knudsen <arve.knudsen@gmail.com>

pkg/tsdb/mssql/mssql.go

@@ -66,33 +66,44 @@ func ParseURL(u string) (*url.URL, error) {
 	}, nil
 }
 
-func generateConnectionString(datasource *models.DataSource) (string, error) {
+func generateConnectionString(dataSource *models.DataSource) (string, error) {
+	const dfltPort = "0"
 	var addr util.NetworkAddress
-	if datasource.Url != "" {
-		u, err := ParseURL(datasource.Url)
+	if dataSource.Url != "" {
+		u, err := ParseURL(dataSource.Url)
 		if err != nil {
 			return "", err
 		}
-		addr, err = util.SplitHostPortDefault(u.Host, "localhost", "1433")
+		addr, err = util.SplitHostPortDefault(u.Host, "localhost", dfltPort)
 		if err != nil {
 			return "", err
 		}
 	} else {
 		addr = util.NetworkAddress{
 			Host: "localhost",
-			Port: "1433",
+			Port: dfltPort,
 		}
 	}
 
-	logger.Debug("Generating connection string", "url", datasource.Url, "host", addr.Host, "port", addr.Port)
-	encrypt := datasource.JsonData.Get("encrypt").MustString("false")
-	connStr := fmt.Sprintf("server=%s;port=%s;database=%s;user id=%s;password=%s;",
+	args := []interface{}{
+		"url", dataSource.Url, "host", addr.Host,
+	}
+	if addr.Port != "0" {
+		args = append(args, "port", addr.Port)
+	}
+
+	logger.Debug("Generating connection string", args...)
+	encrypt := dataSource.JsonData.Get("encrypt").MustString("false")
+	connStr := fmt.Sprintf("server=%s;database=%s;user id=%s;password=%s;",
 		addr.Host,
-		addr.Port,
-		datasource.Database,
-		datasource.User,
-		datasource.DecryptedPassword(),
+		dataSource.Database,
+		dataSource.User,
+		dataSource.DecryptedPassword(),
 	)
+	// Port number 0 means to determine the port automatically, so we can let the driver choose
+	if addr.Port != "0" {
+		connStr += fmt.Sprintf("port=%s;", addr.Port)
+	}
 	if encrypt != "false" {
 		connStr += fmt.Sprintf("encrypt=%s;", encrypt)
 	}

pkg/tsdb/mssql/mssql_test.go

@@ -17,6 +17,7 @@ import (
 	"github.com/grafana/grafana/pkg/tsdb/sqleng"
 	. "github.com/smartystreets/goconvey/convey"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 	"xorm.io/xorm"
 )
 
@@ -32,7 +33,7 @@ var serverIP = "localhost"
 
 func TestMSSQL(t *testing.T) {
 	SkipConvey("MSSQL", t, func() {
-		x := InitMSSQLTestDB(t)
+		x := initMSSQLTestDB(t)
 
 		origXormEngine := sqleng.NewXormEngine
 		sqleng.NewXormEngine = func(d, c string) (*xorm.Engine, error) {
@@ -1161,13 +1162,70 @@ func TestTransformQueryError(t *testing.T) {
 	}
 }
 
-func InitMSSQLTestDB(t *testing.T) *xorm.Engine {
+func TestGenerateConnectionString(t *testing.T) {
+	testCases := []struct {
+		desc       string
+		dataSource *models.DataSource
+		expConnStr string
+	}{
+		{
+			desc: "From URL w/ port",
+			dataSource: &models.DataSource{
+				Url:      "localhost:1001",
+				Database: "database",
+				User:     "user",
+				JsonData: simplejson.NewFromAny(map[string]interface{}{}),
+			},
+			expConnStr: "server=localhost;database=database;user id=user;password=;port=1001;",
+		},
+		// When no port is specified, the driver should be allowed to choose
+		{
+			desc: "From URL w/o port",
+			dataSource: &models.DataSource{
+				Url:      "localhost",
+				Database: "database",
+				User:     "user",
+				JsonData: simplejson.NewFromAny(map[string]interface{}{}),
+			},
+			expConnStr: "server=localhost;database=database;user id=user;password=;",
+		},
+		// Port 0 should be equivalent to not specifying a port, i.e. let the driver choose
+		{
+			desc: "From URL w port 0",
+			dataSource: &models.DataSource{
+				Url:      "localhost:0",
+				Database: "database",
+				User:     "user",
+				JsonData: simplejson.NewFromAny(map[string]interface{}{}),
+			},
+			expConnStr: "server=localhost;database=database;user id=user;password=;",
+		},
+		{
+			desc: "Defaults",
+			dataSource: &models.DataSource{
+				Database: "database",
+				User:     "user",
+				JsonData: simplejson.NewFromAny(map[string]interface{}{}),
+			},
+			expConnStr: "server=localhost;database=database;user id=user;password=;",
+		},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.desc, func(t *testing.T) {
+			connStr, err := generateConnectionString(tc.dataSource)
+			require.NoError(t, err)
+			assert.Equal(t, tc.expConnStr, connStr)
+		})
+	}
+}
+
+func initMSSQLTestDB(t *testing.T) *xorm.Engine {
+	t.Helper()
+
 	testDB := sqlutil.MSSQLTestDB()
 	x, err := xorm.NewEngine(testDB.DriverName, strings.Replace(testDB.ConnStr, "localhost",
 		serverIP, 1))
-	if err != nil {
-		t.Fatalf("Failed to init mssql db %v", err)
-	}
+	require.NoError(t, err)
 
 	x.DatabaseTZ = time.UTC
 	x.TZLocation = time.UTC