feat: add TimestampBound option to ExecOptions

conn.go

@@ -401,6 +401,16 @@ func (c *conn) setReadOnlyStaleness(staleness spanner.TimestampBound) (driver.Re
 	return driver.ResultNoRows, nil
 }
 
+func (c *conn) readOnlyStalenessPointer() *spanner.TimestampBound {
+	val := propertyReadOnlyStaleness.GetConnectionPropertyValue(c.state)
+	if val == nil || !val.HasValue() {
+		return nil
+	}
+	staleness, _ := val.GetValue()
+	timestampBound := staleness.(spanner.TimestampBound)
+	return &timestampBound
+}
+
 func (c *conn) IsolationLevel() sql.IsolationLevel {
 	return propertyIsolationLevel.GetValueOrDefault(c.state)
 }
@@ -987,6 +997,7 @@ func (c *conn) options(reset bool) *ExecOptions {
 			},
 		},
 		PartitionedQueryOptions: PartitionedQueryOptions{},
+		TimestampBound:          c.readOnlyStalenessPointer(),
 	}
 	if c.tempExecOptions != nil {
 		effectiveOptions.merge(c.tempExecOptions)
@@ -1274,6 +1285,9 @@ func (c *conn) rollback(ctx context.Context) error {
 }
 
 func queryInSingleUse(ctx context.Context, c *spanner.Client, statement spanner.Statement, tb spanner.TimestampBound, options *ExecOptions) *spanner.RowIterator {
+	if options.TimestampBound != nil {
+		tb = *options.TimestampBound
+	}
 	return c.Single().WithTimestampBound(tb).QueryWithOptions(ctx, statement, options.QueryOptions)
 }
 

conn_with_mockserver_test.go

@@ -20,6 +20,7 @@ import (
 	"fmt"
 	"reflect"
 	"testing"
+	"time"
 
 	"cloud.google.com/go/longrunning/autogen/longrunningpb"
 	"cloud.google.com/go/spanner"
@@ -587,6 +588,34 @@ func TestSetLocalReadLockMode(t *testing.T) {
 	}
 }
 
+func TestTimestampBound(t *testing.T) {
+	t.Parallel()
+
+	db, server, teardown := setupTestDBConnection(t)
+	defer teardown()
+	ctx := context.Background()
+
+	staleness := spanner.MaxStaleness(10 * time.Second)
+	row := db.QueryRowContext(ctx, testutil.SelectFooFromBar, ExecOptions{TimestampBound: &staleness})
+	if row.Err() != nil {
+		t.Fatal(row.Err())
+	}
+	var val int64
+	if err := row.Scan(&val); err != nil {
+		t.Fatal(err)
+	}
+
+	requests := server.TestSpanner.DrainRequestsFromServer()
+	executeRequests := testutil.RequestsOfType(requests, reflect.TypeOf(&spannerpb.ExecuteSqlRequest{}))
+	if g, w := len(executeRequests), 1; g != w {
+		t.Fatalf("execute requests count mismatch\n Got: %v\nWant: %v", g, w)
+	}
+	request := executeRequests[0].(*spannerpb.ExecuteSqlRequest)
+	if g, w := request.Transaction.GetSingleUse().GetReadOnly().GetMaxStaleness().GetSeconds(), int64(10); g != w {
+		t.Fatalf("read staleness mismatch\n Got: %v\nWant: %v", g, w)
+	}
+}
+
 func TestCreateDatabase(t *testing.T) {
 	t.Parallel()
 

driver.go

@@ -173,6 +173,10 @@ type ExecOptions struct {
 	TransactionOptions spanner.TransactionOptions
 	// QueryOptions are the query options that will be used for the statement.
 	QueryOptions spanner.QueryOptions
+	// TimestampBound is the timestamp bound that will be used for the statement
+	// if it is a query outside a transaction. Setting this option will override
+	// the default TimestampBound that is set on the connection.
+	TimestampBound *spanner.TimestampBound
 
 	// PartitionedQueryOptions are used for partitioned queries, and ignored
 	// for all other statements.
@@ -234,6 +238,9 @@ func (dest *ExecOptions) merge(src *ExecOptions) {
 	if src.AutocommitDMLMode != Unspecified {
 		dest.AutocommitDMLMode = src.AutocommitDMLMode
 	}
+	if src.TimestampBound != nil {
+		dest.TimestampBound = src.TimestampBound
+	}
 	(&dest.PartitionedQueryOptions).merge(&src.PartitionedQueryOptions)
 	mergeQueryOptions(&dest.QueryOptions, &src.QueryOptions)
 	mergeTransactionOptions(&dest.TransactionOptions, &src.TransactionOptions)