Cloudfetch: Allow configuration of httpclient for cloudfetch

connector.go

@@ -260,6 +260,12 @@ func WithAuthenticator(authr auth.Authenticator) ConnOption {
 func WithTransport(t http.RoundTripper) ConnOption {
 	return func(c *config.Config) {
 		c.Transport = t
+
+		if c.CloudFetchConfig.HTTPClient == nil {
+			c.CloudFetchConfig.HTTPClient = &http.Client{
+				Transport: t,
+			}
+		}
 	}
 }
 

connector_test.go

@@ -48,6 +48,7 @@ func TestNewConnector(t *testing.T) {
 			MaxFilesInMemory:             10,
 			MinTimeToExpiry:              0 * time.Second,
 			CloudFetchSpeedThresholdMbps: 0.1,
+			HTTPClient:                   &http.Client{Transport: roundTripper},
 		}
 		expectedUserConfig := config.UserConfig{
 			Host:             host,
@@ -246,6 +247,25 @@ func TestNewConnector(t *testing.T) {
 		require.True(t, ok)
 		assert.False(t, coni.cfg.EnableMetricViewMetadata)
 	})
+
+	t.Run("Connector test WithTransport sets HTTPClient in CloudFetchConfig", func(t *testing.T) {
+		host := "databricks-host"
+		accessToken := "token"
+		httpPath := "http-path"
+		customTransport := &http.Transport{MaxIdleConns: 10}
+		con, err := NewConnector(
+			WithServerHostname(host),
+			WithAccessToken(accessToken),
+			WithHTTPPath(httpPath),
+			WithTransport(customTransport),
+		)
+		assert.Nil(t, err)
+
+		coni, ok := con.(*connector)
+		require.True(t, ok)
+		assert.NotNil(t, coni.cfg.CloudFetchConfig.HTTPClient)
+		assert.Equal(t, customTransport, coni.cfg.CloudFetchConfig.HTTPClient.Transport)
+	})
 }
 
 type mockRoundTripper struct{}

internal/config/config.go

@@ -479,6 +479,7 @@ type CloudFetchConfig struct {
 	MaxFilesInMemory             int
 	MinTimeToExpiry              time.Duration
 	CloudFetchSpeedThresholdMbps float64 // Minimum download speed in MBps before WARN logging (default: 0.1)
+	HTTPClient                   *http.Client
 }
 
 func (cfg CloudFetchConfig) WithDefaults() CloudFetchConfig {

internal/rows/arrowbased/batchloader.go

@@ -34,12 +34,18 @@ func NewCloudIPCStreamIterator(
 	startRowOffset int64,
 	cfg *config.Config,
 ) (IPCStreamIterator, dbsqlerr.DBError) {
+	httpClient := http.DefaultClient
+	if cfg.UserConfig.CloudFetchConfig.HTTPClient != nil {
+		httpClient = cfg.UserConfig.CloudFetchConfig.HTTPClient
+	}
+
 	bi := &cloudIPCStreamIterator{
 		ctx:            ctx,
 		cfg:            cfg,
 		startRowOffset: startRowOffset,
 		pendingLinks:   NewQueue[cli_service.TSparkArrowResultLink](),
 		downloadTasks:  NewQueue[cloudFetchDownloadTask](),
+		httpClient:     httpClient,
 	}
 
 	for _, link := range files {
@@ -140,6 +146,7 @@ type cloudIPCStreamIterator struct {
 	startRowOffset int64
 	pendingLinks   Queue[cli_service.TSparkArrowResultLink]
 	downloadTasks  Queue[cloudFetchDownloadTask]
+	httpClient     *http.Client
 }
 
 var _ IPCStreamIterator = (*cloudIPCStreamIterator)(nil)
@@ -162,6 +169,7 @@ func (bi *cloudIPCStreamIterator) Next() (io.Reader, error) {
 			resultChan:         make(chan cloudFetchDownloadTaskResult),
 			minTimeToExpiry:    bi.cfg.MinTimeToExpiry,
 			speedThresholdMbps: bi.cfg.CloudFetchSpeedThresholdMbps,
+			httpClient:         bi.httpClient,
 		}
 		task.Run()
 		bi.downloadTasks.Enqueue(task)
@@ -210,6 +218,7 @@ type cloudFetchDownloadTask struct {
 	link               *cli_service.TSparkArrowResultLink
 	resultChan         chan cloudFetchDownloadTaskResult
 	speedThresholdMbps float64
+	httpClient         *http.Client
 }
 
 func (cft *cloudFetchDownloadTask) GetResult() (io.Reader, error) {
@@ -252,7 +261,7 @@ func (cft *cloudFetchDownloadTask) Run() {
 			cft.link.StartRowOffset,
 			cft.link.RowCount,
 		)
-		data, err := fetchBatchBytes(cft.ctx, cft.link, cft.minTimeToExpiry, cft.speedThresholdMbps)
+		data, err := fetchBatchBytes(cft.ctx, cft.link, cft.minTimeToExpiry, cft.speedThresholdMbps, cft.httpClient)
 		if err != nil {
 			cft.resultChan <- cloudFetchDownloadTaskResult{data: nil, err: err}
 			return
@@ -300,6 +309,7 @@ func fetchBatchBytes(
 	link *cli_service.TSparkArrowResultLink,
 	minTimeToExpiry time.Duration,
 	speedThresholdMbps float64,
+	httpClient *http.Client,
 ) (io.ReadCloser, error) {
 	if isLinkExpired(link.ExpiryTime, minTimeToExpiry) {
 		return nil, errors.New(dbsqlerr.ErrLinkExpired)
@@ -318,8 +328,7 @@ func fetchBatchBytes(
 	}
 
 	startTime := time.Now()
-	client := http.DefaultClient
-	res, err := client.Do(req)
+	res, err := httpClient.Do(req)
 	if err != nil {
 		return nil, err
 	}

internal/rows/arrowbased/batchloader_test.go

@@ -253,6 +253,85 @@ func TestCloudFetchIterator(t *testing.T) {
 		assert.NotNil(t, err3)
 		assert.ErrorContains(t, err3, fmt.Sprintf("%s %d", "HTTP error", http.StatusNotFound))
 	})
+
+	t.Run("should use custom HTTPClient when provided", func(t *testing.T) {
+		handler = func(w http.ResponseWriter, r *http.Request) {
+			w.WriteHeader(http.StatusOK)
+			_, err := w.Write(generateMockArrowBytes(generateArrowRecord()))
+			if err != nil {
+				panic(err)
+			}
+		}
+
+		startRowOffset := int64(100)
+		customHTTPClient := &http.Client{
+			Transport: &http.Transport{MaxIdleConns: 10},
+		}
+
+		cfg := config.WithDefaults()
+		cfg.UseLz4Compression = false
+		cfg.MaxDownloadThreads = 1
+		cfg.UserConfig.CloudFetchConfig.HTTPClient = customHTTPClient
+
+		bi, err := NewCloudBatchIterator(
+			context.Background(),
+			[]*cli_service.TSparkArrowResultLink{{
+				FileLink:       server.URL,
+				ExpiryTime:     time.Now().Add(10 * time.Minute).Unix(),
+				StartRowOffset: startRowOffset,
+				RowCount:       1,
+			}},
+			startRowOffset,
+			cfg,
+		)
+		assert.Nil(t, err)
+
+		cbi := bi.(*batchIterator).ipcIterator.(*cloudIPCStreamIterator)
+		assert.Equal(t, customHTTPClient, cbi.httpClient)
+
+		// Verify fetch works
+		sab, nextErr := bi.Next()
+		assert.Nil(t, nextErr)
+		assert.NotNil(t, sab)
+	})
+
+	t.Run("should fallback to http.DefaultClient when HTTPClient is nil", func(t *testing.T) {
+		handler = func(w http.ResponseWriter, r *http.Request) {
+			w.WriteHeader(http.StatusOK)
+			_, err := w.Write(generateMockArrowBytes(generateArrowRecord()))
+			if err != nil {
+				panic(err)
+			}
+		}
+
+		startRowOffset := int64(100)
+		cfg := config.WithDefaults()
+		cfg.UseLz4Compression = false
+		cfg.MaxDownloadThreads = 1
+		// Explicitly set HTTPClient to nil to verify fallback behavior
+		cfg.UserConfig.CloudFetchConfig.HTTPClient = nil
+
+		bi, err := NewCloudBatchIterator(
+			context.Background(),
+			[]*cli_service.TSparkArrowResultLink{{
+				FileLink:       server.URL,
+				ExpiryTime:     time.Now().Add(10 * time.Minute).Unix(),
+				StartRowOffset: startRowOffset,
+				RowCount:       1,
+			}},
+			startRowOffset,
+			cfg,
+		)
+		assert.Nil(t, err)
+
+		cbi := bi.(*batchIterator).ipcIterator.(*cloudIPCStreamIterator)
+		assert.Equal(t, http.DefaultClient, cbi.httpClient)
+
+		// Verify fetch works with default client
+		sab, nextErr := bi.Next()
+		assert.Nil(t, nextErr)
+		assert.NotNil(t, sab)
+	})
 }
 
 func generateArrowRecord() arrow.Record {