feat(go/adbc/driver/flightsql): allow passing arbitrary grpc dial opt…

…ions in NewDatabase

Add a new database constructor NewDatabaseWithOptions to allow passing arbitrary user-specified grpc dial options.

This is useful for constructs like
```go
driver := flightsql.NewDriver(memory.DefaultAllocator)
driver.NewDatabaseWithOptions(map[string]string{
		"uri": uri,
	},
	grpc.WithStatsHandler(otelgrpc.NewClientHandler())
)
```

which allows usage of the opentelemetry grpc instrumentation for example.

This also provides an escape valve for users that need the ability to use less commonly used grpc client features that we have not exposed via the string map args.

go/adbc/driver/flightsql/flightsql_database.go

@@ -67,6 +67,7 @@ type databaseImpl struct {
 	dialOpts      dbDialOpts
 	enableCookies bool
 	options       map[string]string
+	userDialOpts  []grpc.DialOption
 }
 
 func (d *databaseImpl) SetOptions(cnOptions map[string]string) error {
@@ -337,7 +338,7 @@ func (d *databaseImpl) Close() error {
 	return nil
 }
 
-func getFlightClient(ctx context.Context, loc string, d *databaseImpl, authMiddle *bearerAuthMiddleware, cookies flight.CookieMiddleware) (*flightsql.Client, error) {
+func getFlightClient(ctx context.Context, loc string, d *databaseImpl, authMiddle *bearerAuthMiddleware, cookies flight.CookieMiddleware, userGrpcDialOpts ...grpc.DialOption) (*flightsql.Client, error) {
 	middleware := []flight.ClientMiddleware{
 		{
 			Unary:  makeUnaryLoggingInterceptor(d.Logger),
@@ -371,6 +372,7 @@ func getFlightClient(ctx context.Context, loc string, d *databaseImpl, authMiddl
 	dv, _ := d.DatabaseImplBase.DriverInfo.GetInfoForInfoCode(adbc.InfoDriverVersion)
 	driverVersion := dv.(string)
 	dialOpts := append(d.dialOpts.opts, grpc.WithConnectParams(d.timeout.connectParams()), grpc.WithTransportCredentials(creds), grpc.WithUserAgent("ADBC Flight SQL Driver "+driverVersion))
+	dialOpts = append(dialOpts, userGrpcDialOpts...)
 
 	d.Logger.DebugContext(ctx, "new client", "location", loc)
 	cl, err := flightsql.NewClient(target, nil, middleware, dialOpts...)
@@ -414,7 +416,7 @@ func (d *databaseImpl) Open(ctx context.Context) (adbc.Connection, error) {
 		cookies = flight.NewCookieMiddleware()
 	}
 
-	cl, err := getFlightClient(ctx, d.uri.String(), d, authMiddle, cookies)
+	cl, err := getFlightClient(ctx, d.uri.String(), d, authMiddle, cookies, d.userDialOpts...)
 	if err != nil {
 		return nil, err
 	}
@@ -435,7 +437,7 @@ func (d *databaseImpl) Open(ctx context.Context) (adbc.Connection, error) {
 			}
 			// use the existing auth token if there is one
 			cl, err := getFlightClient(context.Background(), uri, d,
-				&bearerAuthMiddleware{hdrs: authMiddle.hdrs.Copy()}, cookieMiddleware)
+				&bearerAuthMiddleware{hdrs: authMiddle.hdrs.Copy()}, cookieMiddleware, d.userDialOpts...)
 			if err != nil {
 				return nil, err
 			}

go/adbc/driver/flightsql/flightsql_driver.go

@@ -39,6 +39,7 @@ import (
 	"github.com/apache/arrow-adbc/go/adbc/driver/internal/driverbase"
 	"github.com/apache/arrow-go/v18/arrow/memory"
 	"golang.org/x/exp/maps"
+	"google.golang.org/grpc"
 	"google.golang.org/grpc/metadata"
 )
 
@@ -77,12 +78,15 @@ type driverImpl struct {
 }
 
 // NewDriver creates a new Flight SQL driver using the given Arrow allocator.
+//
+// It optionally accepts gRPC dial options to be used when connecting to the
 func NewDriver(alloc memory.Allocator) adbc.Driver {
 	info := driverbase.DefaultDriverInfo("Flight SQL")
 	return driverbase.NewDriver(&driverImpl{DriverImplBase: driverbase.NewDriverImplBase(info, alloc)})
 }
 
-func (d *driverImpl) NewDatabase(opts map[string]string) (adbc.Database, error) {
+// NewDatabase creates a new Flight SQL database using the given options.
+func (d *driverImpl) NewDatabaseWithOptions(opts map[string]string, userDialOpts ...grpc.DialOption) (adbc.Database, error) {
 	opts = maps.Clone(opts)
 	uri, ok := opts[adbc.OptionKeyURI]
 	if !ok {
@@ -99,7 +103,8 @@ func (d *driverImpl) NewDatabase(opts map[string]string) (adbc.Database, error)
 			// Match gRPC default
 			connectTimeout: time.Second * 20,
 		},
-		hdrs: make(metadata.MD),
+		hdrs:         make(metadata.MD),
+		userDialOpts: userDialOpts,
 	}
 
 	var err error
@@ -118,3 +123,8 @@ func (d *driverImpl) NewDatabase(opts map[string]string) (adbc.Database, error)
 
 	return driverbase.NewDatabase(db), nil
 }
+
+// NewDatabase creates a new Flight SQL database using the given options.
+func (d *driverImpl) NewDatabase(opts map[string]string) (adbc.Database, error) {
+	return d.NewDatabaseWithOptions(opts)
+}