func newExportTask()

in tools/mc2bq/pkg/export/export.go [80:124]
40 lines of code
7 McCabe index (conditional complexity)

func newExportTask(ctx context.Context, dataset *bigquery.Dataset, params *Params, src mcutil.ObjectSource, tableSuffix string, objectCount uint64) func() error {
	tblName := params.TablePrefix + tableSuffix
	return func() error {
		done := make(chan bool, 1)
		defer close(done)
		go func() {
			const timeout = 5 * time.Second
			timer := time.NewTimer(timeout)
			for {
				select {
				case <-done:
					timer.Stop()
					return
				case <-timer.C:
					if src.ObjectsRead() == objectCount || src.ObjectsRead() == 0 {
						// Don't write progress if we haven't started or just finished
						continue
					}
					fmt.Println(messages.ExportTableInProgress{
						TableName:          tblName,
						RecordsTransferred: src.ObjectsRead(),
						RecordCount:        objectCount,
						BytesTransferred:   src.BytesRead(),
					})
					timer.Reset(timeout)
				}
			}
		}()

		err := exportObjects(ctx, dataset, params, src, tblName)
		if err != nil {
			return fmt.Errorf("export %s: %w", tableSuffix, err)
		}

		done <- true

		fmt.Println(messages.ExportTableComplete{
			TableName:        tblName,
			RecordCount:      src.ObjectsRead(),
			BytesTransferred: src.BytesRead(),
		})

		return nil
	}
}