constellation/debugd/internal/bootstrapper/streamer.go

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package bootstrapper
import (
"errors"
"fmt"
"io"
"os"
"sync"
pb "github.com/edgelesssys/constellation/debugd/service"
"github.com/schollz/progressbar/v3"
"github.com/spf13/afero"
)
// FileStreamer handles reading and writing of a file using a stream of chunks.
type FileStreamer struct {
fs afero.Fs
mux sync.RWMutex
}
// ReadChunkStream is abstraction over a gRPC stream that allows us to receive chunks via gRPC.
type ReadChunkStream interface {
Recv() (*pb.Chunk, error)
}
// WriteChunkStream is abstraction over a gRPC stream that allows us to send chunks via gRPC.
type WriteChunkStream interface {
Send(chunk *pb.Chunk) error
}
// NewFileStreamer creates a new FileStreamer.
func NewFileStreamer(fs afero.Fs) *FileStreamer {
return &FileStreamer{
fs: fs,
mux: sync.RWMutex{},
}
}
// WriteStream opens a file to write to and streams chunks from a gRPC stream into the file.
func (f *FileStreamer) WriteStream(filename string, stream ReadChunkStream, showProgress bool) error {
// try to read from stream once before acquiring write lock
chunk, err := stream.Recv()
if err != nil {
return fmt.Errorf("reading stream: %w", err)
}
f.mux.Lock()
defer f.mux.Unlock()
file, err := f.fs.OpenFile(filename, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0o755)
if err != nil {
return fmt.Errorf("open %v for writing: %w", filename, err)
}
defer file.Close()
var bar *progressbar.ProgressBar
if showProgress {
bar = progressbar.NewOptions64(
-1,
progressbar.OptionSetDescription("receiving bootstrapper"),
progressbar.OptionShowBytes(true),
progressbar.OptionClearOnFinish(),
)
defer bar.Close()
}
for {
if err != nil {
if errors.Is(err, io.EOF) {
break
}
_ = file.Close()
_ = f.fs.Remove(filename)
return fmt.Errorf("reading stream: %w", err)
}
if _, err := file.Write(chunk.Content); err != nil {
_ = file.Close()
_ = f.fs.Remove(filename)
return fmt.Errorf("writing chunk to disk: %w", err)
}
if showProgress {
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_ = bar.Add(len(chunk.Content))
}
chunk, err = stream.Recv()
}
return nil
}
// ReadStream opens a file to read from and streams its contents chunkwise over gRPC.
func (f *FileStreamer) ReadStream(filename string, stream WriteChunkStream, chunksize uint, showProgress bool) error {
if chunksize == 0 {
return errors.New("invalid chunksize")
}
// fail if file is currently RW locked
if f.mux.TryRLock() {
defer f.mux.RUnlock()
} else {
return errors.New("file is opened for writing cannot be read at this time")
}
file, err := f.fs.OpenFile(filename, os.O_RDONLY, 0o755)
if err != nil {
return fmt.Errorf("open %v for reading: %w", filename, err)
}
defer file.Close()
var bar *progressbar.ProgressBar
if showProgress {
stat, err := file.Stat()
if err != nil {
return fmt.Errorf("performing stat on %v to get the file size: %w", filename, err)
}
bar = progressbar.NewOptions64(
stat.Size(),
progressbar.OptionSetDescription("uploading bootstrapper"),
progressbar.OptionShowBytes(true),
progressbar.OptionClearOnFinish(),
)
defer bar.Close()
}
buf := make([]byte, chunksize)
for {
n, err := file.Read(buf)
if err != nil {
if errors.Is(err, io.EOF) {
return nil
}
return fmt.Errorf("reading file chunk: %w", err)
}
if err = stream.Send(&pb.Chunk{Content: buf[:n]}); err != nil {
return fmt.Errorf("sending chunk: %w", err)
}
if showProgress {
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_ = bar.Add(n)
}
}
}