Merge pull request #1580 from dolthub/port-in-use

Better error message for starting a server on a port in use

go/cmd/dolt/commands/sqlserver/server.go

@@ -16,6 +16,7 @@ package sqlserver
 
 import (
 	"context"
+	"fmt"
 	"net"
 	"strconv"
 	"time"
@@ -123,7 +124,14 @@ func Serve(ctx context.Context, version string, serverConfig ServerConfig, serve
 
 	sqlEngine.AddDatabase(information_schema.NewInformationSchemaDatabase(sqlEngine.Catalog))
 
-	hostPort := net.JoinHostPort(serverConfig.Host(), strconv.Itoa(serverConfig.Port()))
+	portAsString := strconv.Itoa(serverConfig.Port())
+	hostPort := net.JoinHostPort(serverConfig.Host(), portAsString)
+
+	if portInUse(hostPort) {
+		portInUseError := fmt.Errorf("Port %s already in use.", portAsString)
+		return portInUseError, nil
+	}
+
 	readTimeout := time.Duration(serverConfig.ReadTimeout()) * time.Millisecond
 	writeTimeout := time.Duration(serverConfig.WriteTimeout()) * time.Millisecond
 	mySQLServer, startError = server.NewServer(
@@ -155,6 +163,16 @@ func Serve(ctx context.Context, version string, serverConfig ServerConfig, serve
 	return
 }
 
+func portInUse(hostPort string) bool {
+	timeout := time.Second
+	conn, _ := net.DialTimeout("tcp", hostPort, timeout)
+	if conn != nil {
+		defer conn.Close()
+		return true
+	}
+	return false
+}
+
 func newSessionBuilder(sqlEngine *sqle.Engine, username, email string, autocommit bool) server.SessionBuilder {
 	return func(ctx context.Context, conn *mysql.Conn, host string) (sql.Session, *sql.IndexRegistry, *sql.ViewRegistry, error) {
 		mysqlSess := sql.NewSession(host, conn.RemoteAddr().String(), conn.User, conn.ConnectionID)

go/cmd/dolt/commands/sqlserver/server_test.go

@@ -15,6 +15,7 @@
 package sqlserver
 
 import (
+	"net/http"
 	"strings"
 	"testing"
 
@@ -216,3 +217,27 @@ func TestServerSelect(t *testing.T) {
 		})
 	}
 }
+
+// If a port is already in use, throw error "Port XXXX already in use."
+func TestServerFailsIfPortInUse(t *testing.T) {
+	serverController := CreateServerController()
+	server := &http.Server{
+		Addr:    ":15200",
+		Handler: http.DefaultServeMux,
+	}
+	go server.ListenAndServe()
+	go func() {
+		startServer(context.Background(), "test", "dolt sql-server", []string{
+			"-H", "localhost",
+			"-P", "15200",
+			"-u", "username",
+			"-p", "password",
+			"-t", "5",
+			"-l", "info",
+			"-r",
+		}, dtestutils.CreateEnvWithSeedData(t), serverController)
+	}()
+	err := serverController.WaitForStart()
+	require.Error(t, err)
+	server.Close()
+}

integration-tests/bats/sql-server.bats

@@ -20,6 +20,19 @@ teardown() {
     teardown_common
 }
 
+@test "sql-server: port in use" {
+    cd repo1
+
+    let PORT="$$ % (65536-1024) + 1024"
+    dolt sql-server --host 0.0.0.0 --port=$PORT --user dolt &
+    SERVER_PID=$! # will get killed by teardown_common
+    sleep 5 # not using python wait so this works on windows
+    
+    run dolt sql-server --host 0.0.0.0 --port=$PORT --user dolt
+    [ "$status" -eq 1 ]
+    [[ "$output" =~ "in use" ]] || false
+}
+
 @test "sql-server: multi-client" {
     skiponwindows "Has dependencies that are missing on the Jenkins Windows installation."
 
@@ -715,4 +728,4 @@ SQL
 
     insert_query 1 "INSERT INTO js_test VALUES (1, '{\"a\":1}');"
     server_query 1 "SELECT * FROM js_test;" "pk,js\n1,{\"a\": 1}"
-}
+}