GODRIVER-3841 Support concurrent *GridFSBucket.OpenUploadStream calls.

internal/integration/gridfs_test.go

@@ -11,14 +11,17 @@ import (
 	"context"
 	"io"
 	"math/rand"
+	"os"
 	"runtime"
+	"sync"
 	"testing"
 	"time"
 
 	"go.mongodb.org/mongo-driver/v2/bson"
 	"go.mongodb.org/mongo-driver/v2/event"
 	"go.mongodb.org/mongo-driver/v2/internal/assert"
 	"go.mongodb.org/mongo-driver/v2/internal/integration/mtest"
+	"go.mongodb.org/mongo-driver/v2/internal/integtest"
 	"go.mongodb.org/mongo-driver/v2/internal/israce"
 	"go.mongodb.org/mongo-driver/v2/internal/require"
 	"go.mongodb.org/mongo-driver/v2/mongo"
@@ -529,6 +532,41 @@ func TestGridFS(x *testing.T) {
 	})
 }
 
+func TestOpenUploadStreamConcurrently(t *testing.T) {
+	t.Parallel()
+
+	uri, err := integtest.MongoDBURI()
+	require.NoError(t, err, "error getting URI: %v", err)
+	opts := options.Client().ApplyURI(uri)
+	if os.Getenv("REQUIRE_API_VERSION") == "true" {
+		opts.SetServerAPIOptions(options.ServerAPI(options.ServerAPIVersion1))
+	}
+	client, err := mongo.Connect(opts)
+	require.NoError(t, err, "Connect error: %v", err)
+	defer func() {
+		_ = client.Disconnect(context.Background())
+	}()
+
+	db := client.Database(mtest.TestDB)
+	bucket := db.GridFSBucket()
+	defer func() {
+		_ = bucket.Drop(context.Background())
+	}()
+
+	const size = 10_000
+
+	wg := sync.WaitGroup{}
+	wg.Add(size)
+	for i := 0; i < size; i++ {
+		go func() {
+			defer wg.Done()
+			_, err := bucket.OpenUploadStream(context.Background(), "foo")
+			assert.NoError(t, err, "OpenUploadStream error: %v", err)
+		}()
+	}
+	wg.Wait()
+}
+
 func assertGridFSCollectionState(mt *mtest.T, coll *mongo.Collection, expectedName string, expectedNumDocuments int64) {
 	mt.Helper()
 

mongo/gridfs_bucket.go

@@ -12,6 +12,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"sync/atomic"
 
 	"go.mongodb.org/mongo-driver/v2/bson"
 	"go.mongodb.org/mongo-driver/v2/internal/csot"
@@ -37,6 +38,8 @@ var ErrMissingGridFSChunkSize = errors.New("files collection document does not c
 
 // GridFSBucket represents a GridFS bucket.
 type GridFSBucket struct {
+	firstWriteDone uint32
+
 	db         *Database
 	chunksColl *Collection // collection to store file chunks
 	filesColl  *Collection // collection to store file metadata
@@ -47,9 +50,8 @@ type GridFSBucket struct {
 	rc        *readconcern.ReadConcern
 	rp        *readpref.ReadPref
 
-	firstWriteDone bool
-	readBuf        []byte
-	writeBuf       []byte
+	readBuf  []byte
+	writeBuf []byte
 }
 
 // upload contains options to upload a file to a bucket.
@@ -531,14 +533,10 @@ func (b *GridFSBucket) createIndexes(ctx context.Context) error {
 }
 
 func (b *GridFSBucket) checkFirstWrite(ctx context.Context) error {
-	if !b.firstWriteDone {
+	if atomic.CompareAndSwapUint32(&b.firstWriteDone, 0, 1) {
 		// before the first write operation, must determine if files collection is empty
 		// if so, create indexes if they do not already exist
-
-		if err := b.createIndexes(ctx); err != nil {
-			return err
-		}
-		b.firstWriteDone = true
+		return b.createIndexes(ctx)
 	}
 
 	return nil